AWG-10 WCS and APG-59 Radar

overscan

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I'd really like to learn more about the F-4J avionics, including the APG-59 radar and the VTAS helmet mounted sight.

Here's two shots of the APG-59 radar; the first is a McDonnell-Douglas provided promotional picture, showing a prototype radar, the second picture is an operational radar.

Source:
  • Bert Kinzey Detail & Scale 012 F-4 Phantom II (3) - USN & USMC, Arms & Armour Press, 1983
 

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t was always fun when we got a "new" bird - nOT! You F/A-18 fixers don't know what you missed; it doesn't even concern you nowadays. If the pilot or RIO sees co-channel interference from another plane, he just pushes a button to change channels. That wasn't so in the good ol' F-4J's and F-4S's, as they were "manually" tuned.
There were 18 frequencies used, all X-band (9ghz), and since you had 12 birds in a squadron, the odds of getting a new bird in a "wrong" frequency was really high. You wouldn't want to send out a flight of Phantoms that were closer than 2 channels from each other, because the radars would pretty much "jam" each other, or overload each other's receivers with radar energy. So, we'd get to re-tune 'em, which meant a buttload of work:
1) Open the radome, insert the package extension rail.
2) Extend the radar package after removing the 4 nuts from the X-frame.
3) Connect air conditioning from the -8 and power from the -60
4) Select the channel range on LRU-6A2
5) Select the channel range on the 4A3A7 board.
6) R&R the two filters out of the 2A8 (Receiver)
7) Wait for COM/NAV to replace the filters in the turtleback
8) Fire up the radar, warm it up until the transmitter kicked in (5 minutes)
9) Re-tune the main KPA (Klystron Power Amplifier, 1,525 watts) by adjusting the four struts, de-tune strut #3 to obtain maximum power
10) Re-tune the CW Illuminator KPA using same procedure (the CW Illuminator generated the RF signal the Sparrow missiles followed to their target)
11) Button it up, and you're done ... but put a new set of KPA's on order, because they don't like being tuned to a new frequency, and you can bet your arse you'll be putting in a new set within two weeks. Oh, joy! Roll Eyes Wink

Such were the joys of a 'Nam-era F-4 radar tech We busted are azzes, and learned a lot.
Funny, I hadn't worked on one of those birds in 25 years, but still have the routine pretty well down pat Wink

S/F,
Wook
http://forums.military.com/eve/ubb.x/a/tpc/f/5671946761/m/254105031
 

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AWG-10 (APG-59)

Provides pulse and pulse doppler air/air search/track, high/low map modes, and air to ground ranging.
First deployed in 1968
29 LRUs

AWG-10A

Enhanced reliability part digital version. Only 3 LRUs unchanged, 6 new, 7 deleted, 9 modified in varying degrees. Adds one air/air [close combat] and three air/ground modes. Improved built-in-test capability.

AWG-10B
Final "all-digital" version of F-4S

Source:

Jane's Weapon Systems 1981
 

overscan

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the APG-59 is credited with 1 kw, but that's Pavg, with a 44% duty cycle. Avg.
detection range on a 5m.^2 target is 60nm. I don't know if that's for a
50%, 90% or other % probability of detection.
Guy Alacala, Usenet discussion.

32 in (810mm) diameter antenna

Heavier and bulkier than APQ-72
Jon Lake ed. McDonnell-Douglas F-4 Phantom: Spirit in the Skies Aerospace Publishing, 1992
 

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Interesting that you found my old post up there.

I was an MOS 6657, airborne missile fire control technician on F-4J and F-4S Phantom II's during my six-year tour in the Marine Corps.

In the top photo, the radar antenna (LRU-1, LRU=Line Replaceable Unit)) has no IFF antennas (Identification, Friend or Foe). On the port side of the antenna (or right side as you're looking at it) is a rectangular funnel-shaped object, which is the CW illuminator feedhorn. The main KPA (Klystron Power Amplifier) is 1525 watts, and the CW illuminator KPA is around 900 watts. It was necessary to provide the illuminator KPA for the AIM-7 Sparrow missiles' guidance, as even though the illuminator KPA was rated at a much lower power than the main KPA, the most the main KPA could be on for TX/RX was less than a 50% duty cycle, reducing it's effective power to well below that of the CW KPA. Signal from the CW KPA was also fed via coaxial cable to the rear of the four onboard missile stations, for the Sparrows to get a "lock" on. Early Sparrows had mechanical tuners, which were problematic; one ordinance technican found that you could get them "unstuck" using a large hammer, which action caused the rest of us more cautious and sane types to scatter in all directions.

The APG-59/AWG-10 radar had three basic modes:
1) Short Pulse - a 0.65 uSEC pulse triggered the transmitter to send out the same length pulse. This was the 10 NM mode.

2) Chirp - A 0.65 uSEC pulse was sent through a "delay line" - basically, an inductor which was grounded on one end. This caused the inductor to "ring" as a struck bell, and would cause the transmitter to fire for approximately 65 uSEC. Upon returning, the signal would be fed back across this same delay line, which would compress the pulse back down to about 0.8 uSEC pulsewidth prior to being fed to the receiver (LRU-2A8, bottom starboard side). This meant a slight loss in resolution, but a huge gain in range due to the increased return signal.

3) Pulsed Doppler - the most powerful mode. The transmitter would fire for approximately 40 uS, and then the system would receive for approximately 40 uS. The PRF (Pulse Repetition Frequency) would be varied constantly to avoid a phenomenon known as "target eclipsing" (when the transmitter is on while the return signal comes back.)

Back to the LRU-1 photo at the top: Notice that there is a rectangular panel about 1/3 of the way down the antenna? That is the Beam Spoiler, and was used for PPI/MAP mode (Plan Position Indicator) - it would extend about 1" to "spoil" the radiation pattern to scan the ground. On the scope, the sweep would scan back and fourth 120º (+-60º) and the bottom of the scan would be fixed, the top (furthest away) would look like a Japanese fan, or a section of pie, if you will.

In combat modes, the sweep was vertical, traversing the entire screen.

In the 2nd picture, the eight black T-shaped items on the front of the antenna are IFF antennas. They are white on one end (the top) of the "T" to indicate the polarity of the antenna; as putting some of them on backwards would foul up the signal.

The feedhorn is the long projection from the center of the antenna. At the forward end, there are thin fiberglass covers epoxied over the feedhorn, enabling the waveguide system to be pressurized with dry air to 14 lbs/in2 so that the RF energy wouldn't arc (short out) in the waveguide. The feedhorn directed the transmitted energy back against the dish, and received the signal the same way. When the RIO (Radar Intercept Officer) initiated a lock, the feedhorn support would begin to rotate at 66 RPM, causing slight rotational shifts in the position of the feedhorn; this was known as "nutating the feedhorn." This shifting would cause the radar to "paint a donut" around the target. The radar would detect the difference in signal return around the "donut", and re-orient the antenna so that the signal strength was equal all around.

The antenna was controlled by servos and resolvers, but driven by hydraulic pressure. The Phantom's hydraulic system was pressurized to 3,000 PSI, but the antenna's supply was regulated down to 1,200 PSI.

Of all the radars' modes, PD (Pulse Doppler) was the mode that was the hardest to get used to, and somewhat more difficult to fix.

In PD mode, targets were not displayed in range, but in terms of closing velocity, or Vc! Targets near the top of the scope were closing very rapidly, while targets near the bottom were going away. The range was about 1,600 knots closing to about 500 opening. In order to determine the range, the pilot or RIO would have to lock on to the target, and then a range gate would appear as a blip to show range.

The AWG-10A was a big improvement; LRU's 15,16,and 17 (analog computers) in the turtleback (panel 19 behind the RIO) were changed, the new LRU's 15 and 16 were digital, LRU-17 deleted. The analog
version described the missile's envelope as a truncated cone, which was grossly inadequate. The AWG-10A's missile envelope was more like a mushroom, if you will - and much more accurately described the lethal zone of the missiles.

Back to the 2nd picture: the "6" equipment rack is down. LRU-6A2 is on the bottom, LRU-6A1 on top. The 6A1 dealt mostly with antenna control, the 6A2 with the CW illuminator.

To the left (forward) is the "5" equipment rack, and just behind the X-frame is the "4" equipment rack.
On the top of the "4" rack is LRU 4A1, down from there is LRU-4A2, and on the bottom is the LRU-4A3
Inside the LRU-4A2 are 290 crystal ovens, each a different frequency, which resonated to signal returns in the PD mode, thus giving the Vc (velocity closing) range (roughly -500kts to 1500kts)

I realize now that I misspoke in my prior post - it was the 4A1A7 board, not the 4A3A7, that needed to be changed for frequency selection. The 4A3A7 board had it's own problems - there was a block of Zener diodes, which if blown, would cause an effect known as "picket fencing" on the display; the PRF would change every 60 ms causing the display to have vertical streaks on it.

VTAS - (Visual Target Acquisition System) In later versions, VTAS was implemented. The pilot wore a special helmet with four IR transmitters on it, and there were IR receivers mounted around the pilot's cockpit. The pilot's helmet had a reticle; he would extend it over his right eye, and look at the target while pressing half-action on the acquisition switch on his stick. The radar would sweep out in range, and acquire the target. As far as I can remember, this only worked in 10-mile range, or "short pulse". But, like I said - it's been a long time since I've worked on them.

[edited for minor corrections]
 

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A very interesting post indeed., Thanks for sharing!
 

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SgtWookie, that was the single most informative post I have read about AN/AWG-10 in my forum's life, many many thanks!

Could you comment more on that radar, per example:

a) How many radar modes did the RIO has for air combat (BVR and ACM) and how were the scan patterns in azimut and elevation (bars).

b) You commented that the PD mode was the most difficult to use and based on velocity closure (range rate) and not in range vs azimut. That means something like "VS" mode on AN/APG-68 I mean, that's a HPRF mode isn't?. Do you remind any interesting peculiarity of those modes, per example how did they worked according to different clutter environments and target profile?, was that mode only LD or it was also available as a Look up option?

c) Can you comment on the MTBF of the radar set, compared to other radars on Phantom and vintage aircraft you know?, it introduced LRU philosopohy?, how it was to mantain?, would be delighted (and guess most of us) to hear more about your job ;D

d) Did the radar interfaced with advanced con scan Sparrow (AIM-7F) and monopulse Sparrow (AIM-7M) missiles?...

Thanks a lot for any answer and for the last post.
 

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Pit said:
SgtWookie, that was the single most informative post I have read about AN/AWG-10 in my forum's life, many many thanks!
You're welcome - although, in retrospect, I incorrectly corrected my first post! (are you confused yet, because I am ;)) The numbering system for the WRA's/LRU's (same thing) was just a little bit confusing, because on the port side of the radar, the numbers increased from forward to aft, (eg: antenna=LRU 1, then LRU 4 was the entire pallet (but never removed as an entire unit), LRU 5 (never entirely removed as such) and LRU 6. Then, on the 4 pallet, 4A1 was the topmost 3rd, 4A2 was the center unit, and the 4A3 was on the bottom. You can see on the 4A1 and 4A3 units what looks like ribs, those are actually removeable "boards", sort of the shape of a watermelon slice. They're held in place by one (slotted and hex-head) captured screws, one on top and one at the bottom.

On the starboard side, the LRU 2A1 was the transmitter control box, on the top of the package. It was long and relatively thin, shaped rather like a piece of wall to floor molding, only thicker (and aluminum) Below that was "the hat" - a large aluminum cover that was held on with what seemed like a zillion #8 Phillips-head screws. This "hat" was the cover for the pressurized (air, to 14 lbs/in2) transmitter power supply compartment.
There were two separate power supplies, one for the CW illuminator KPA, and one for the main KPA. I believe the LRU 2A2 CW supply put out 22,000 volts, and the main 2A3 supply put out 25,000 volts - at high power. Those supplies were about the size of a loaf of bread each, but were VERY heavy. There were high-power rectifier tubes in those supplies that had large cooling fins on the bottom - as a matter of fact, they made very cool ashtrays when the tubes went bad (I had one for many years, and the wife threw it out!! Arrrgh!)

Could you comment more on that radar, per example:

a) How many radar modes did the RIO has for air combat (BVR and ACM) and how were the scan patterns in azimut and elevation (bars).
There were six "bars" that I remember. I don't recall the starting bar, but if the bars were numbered as such:
1
2
3
4
5
6
I believe the vertical scan pattern went something like: 2,4,1,5,6,3
It wasn't quite what one would expect. I don't recall it changing the bar scan pattern - but remember, the last time I worked on those things was 27 years ago.

As far as modes - they could select PULSE, PD (both ACM modes) A/G (which was the ground mapping feature, 120º PPI (Plan Position Indicator) mode) and I believe T/C or TERRAIN - this last very obscure feature was very difficult for aircrew to understand; it was supposed to indicate to them the likelyhood of collision with terrain features when proceeding at high speed, low altitudes (eg:bombing runs). The antenna scan pattern was that of a "+" - Full Up, Full Down, Center, Full Port, Full Starboard, Center (repeat) The scan displays on both scopes was also a "+". However, a number of crashes occurred while using this mode, and it's use was discouraged by modifying a card in the LRU-10 (Cockpit Display Unit, aft cockpit, port side, just under the canopy rail) to display a large "X" on the screen. As mentioned above, the pilot could select DOGFIGHT mode, which would override the RIO's controls, select short pulse, 10 mile range, and enable VTAS acquisition by sweeping out the range gate upon the pilot's pressing the lower button on his joystick.

The RIO had his own joystick, mounted to the right of the scope and above it. The RIO's stick was about the size of a screwdriver handle, or straight sausage-shaped on a ball mount. It had an "action" button under the middle finger, and a thumbwheel on the top. The thumbwheel controlled the antenna's elevation. The elevation was indicated on the scope as a short horizontal blip on the right side of the screen. Pressing the button halfway down was called "half-action", this would cause the antenna to be slaved to the RIO's stick, and would initiate 60ms PRF switching to prevent target eclipsing.

There was also the "taboo" mode, "EMERGENCY". This mode was to be used ONLY if you were in actual combat, and you had a transmitter failure. This mode overrode all of the thermal sensors, and a number of other protection circuits. Selecting this mode might enable the transmitter to work for a short period of time, but at the likely cost of destroying a number of radar components. When a RIO selected this mode, it tripped a red flag on the knob, which could only be re-set by removing the knob with a small Allen-type wrench. That was one of the very first things we would check after a flight - if that flag was out, the RIO got a trip up to the Skipper's office for an ass-chewing.

There may be more modes that I've forgotten. The last couple of years I was on active duty, we got F-4S's with the AWG-10A's in them, then I transferred to VMFA-122 which had the older F-4J's with AWG-10's again. One can't remember everything from 27 years ago ;)

b) You commented that the PD mode was the most difficult to use and based on velocity closure (range rate) and not in range vs azimut. That means something like "VS" mode on AN/APG-68 I mean, that's a HPRF mode isn't?. Do you remind any interesting peculiarity of those modes, per example how did they worked according to different clutter environments and target profile?, was that mode only LD or it was also available as a Look up option?
PRF was approximately 40ms in PD mode; but remember there still was minute adjustments made to the PRF at the end of every scan, and it would switch every 60ms during half-action or acquisition.

One interesting aspect of the PD mode was the ground clutter notch. This looked rather like an inverted arch. The faster the aircraft was travelling, the taller and narrower the arch was. It was, literally, a "black hole" - the radar would not "see" anything in that notch. It would take digital signal processing to make use of that ground clutter return, which wasn't until later. Remember, the electronics in the AWG-10 were quite crude by today's standards - their idea of an integrated circut back then was a collection of discrete components surrounded by a black cube of epoxy. This is also what made it so difficult to repair, and gave it a low MTBF.

c) Can you comment on the MTBF of the radar set, compared to other radars on Phantom and vintage aircraft you know?, it introduced LRU philosophy?, how it was to mantain?, would be delighted (and guess most of us) to hear more about your job ;D
The MTBF on the original AWG-10 radars we had was quite dismal; if an aircraft was still "up and up" (airframes/radar) for three "hops" (sorties) it was golden. Remember, these aircraft were doggone old by the time I got to operational squadrons back in 1975; they were all Vietnam Veterans, and had seen MANY launches/recoveries from aircraft carriers, and were very high-time airframes. A single F-4J Phantom had 15 miles of wire in it. That's a lot of wiring to maintain. Much of it involved the radar. And the radar had quite a few electro-mechanical relays. One of our most frustrating "gripes" would be, "Radar breaks lock under G's" to which we could only reply "G-force simulator on back order." They wouldn't let technicians fly in the backseat - so we couldn't begin to troubleshoot it.

The BIT box (LRU-8) was a troublesome piece of equipment (BIT=Built-In Test) - it was driven by a film strip with written instructions and frame numbers to tell you where it was in the test, and a grid of (logical) 1's or 0's (either black or see-through) that drove a series of either phototransistors or photoresistors, which controlled a "relay tree" above the antenna that would select various circuits to test. This thing was a nightmare in itself. The AWG-10A BIT box was infinitely better; it was all digital, and markedly faster.

When my 1st squadron got the very first F-4S's with the AWG-10A radars in them, we found them to be VERY reliable in comparison - we were getting 10, 20, 30 or more hops between repairs. However, the first time we went to swap out a computer (LRU15 or LRU16, can't remember which) in the turtleback (behind the RIO) we discovered that the computer harness had been made too short! We got the cables off OK, but they just wouldn't go back on the new computer. They'd made an error in measuring the "jig" used to build the cables.

The F-4S's had other teething problems. They changed from the old flammable hydraulic fluid to a new, non-flammable hydraulic fluid; however the old O-ring seals were not compatible with this new fluid. Well, they supposedly replaced all of the O-rings when the airframes were rebuilt, but they missed a few in the turtleback area, causing eventual massive hydraulic leaks and our squadron to nearly lose an aircraft after losing all hydraulic pressure during approach.[/quote]

d) Did the radar interfaced with advanced con scan Sparrow (AIM-7F) and monopulse Sparrow (AIM-7M) missiles?...
I left the Corps before those missiles were available. The Sparrow missiles I worked with connected to the missile umbilical using a 32-pin shear "wafer". When the missile was ejected from the rack (by firing what amounts to a blank shotgun-shell type device) the wafer would actually shear in half; one side would remain attached to the missle, the other half would stay with the harness. I have a couple of these "wafers" left from my tour in the Corps; I was using them to build Sparrow missile simulators so the aircrew could practice locking on the radar and firing when the missile was inside the envelope. Don't have any photos - yet. They're rather crude, we didn't have any circuit card material available - just soldered together a dozen resistors, capacitors and diodes along with a fuse holder, then potted the whole thing.

Thanks a lot for any answer and for the last post.
You're welcome - hope this is enough for the moment. It's after midnight here, it's been an event-filled day, and I have more to accomplish before hitting the rack.

More to come...
 

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OK, here's an attempt to label some of the components; at least the visible LRU's.

Slight mistake - the channel switch on the 4A3A4 board is actually slightly down and to the right of where I circled it. If you load the pic into an editor and enlarge it, you can faintly see a slightly brighter rectangular area - that is the instruction label for the switch, indicating what channel range each switch setting was for; I don't recall whether each position covered three or four channels.

At the top - "Package extension rail" - this was a long, heavy, rectangular bar made of stainless steel (the aircraft nose end) and aluminum (towards the antenna); it was nearly twice as long as the radar package (less antenna) is deep. The whole package weighed between 650 and 750 lbs, so the package extension rail had to be quite sturdy. The end has a funny-looking shape to it, because there was a lever in it that would swing 90° to lock the rail into position, and then a safety catch would pop out about 1/4" to prevent the lever from returning to horizontal by itself. Without the lever latching the stop in place, the momentum of the radar package could easily cause the entire radar set to over-extend, causing extensive damage to the umbilical and umbilical catenary (shown) The umbilical and catenary actually made nearly a full circle of the rear of the package, to assure the minimum flexing of the wiring without adding undue length (and resistance) to the harness.

The AOA probe (Angle of Attack) I found quite interesting. The probe was very hot when the aircraft was being readied for flight. The probe was basically a hollow cone, with two horizontal slots in it, both facing forward, one about 45º above horizontal, and one the same distance below horizontal. When at flight speeds, the probe could rotate, and the air pressure against the slots would cause the probe to rotate so that the slots were always eqidistant from the center of the airstream pressure, thus giving the angle of attack.

On the forward side of LRU 4A1 is the 4A1A1 board, which is smaller than all the rest. The dark rectangles below it are relays, the purpose of which eludes me after all these years. On the 4A2, the horizontal dark strip is a label. On the far right edge of the 4A2, there is a 50-pin D-type connector oriented vertically, with a white plastic cover on it. There are two more in the middle of the 5A2. Below that, there are dark areas on the 5A3. Believe it or not, on the left (forward) side of the 5A3 there are spare fuses; three of the spare fuseholders are occupied, the other three are empty. The dark rectangles to the right of the rib are more relays.

Just a portion of the relay tree is visible. The miserable thing seemed to cover the entire forward upper starboard quadrant of the package. As they aged, they would become unreliable and cause really odd malfunctions under G forces. I have a few samples of these relays from when I was constructing a special piece of test gear for the transmitter section; a light sequencer you could read from the rear cockpit to tell if all criteria were met for powering up the main and CW KPA's. Never got to complete the project, as by the time all the parts came in, we were changing to the F-4S's, and there were many changes to the transmitter section which negated the need for the special test gear.

These relays are probably 30 years old - but never been used. I'll bet they'll still work ;) I think I'll use some of them in an A-4B Skyhawk we're currently restoring ;D
 

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More on the 50-pin "D"-type connectors... (forgot to explain them in the previous post)

We had a piece of test gear we called a "50-pin box" - certainly not the correct nomenclature, but all the Radar techs called it that. This box had an umbilical cord about 8' long with a 50-pin male D-type connector on it, that we would plug into the matching female LRU connector.

The 50-pin box itself was painted yellow, was about 1'x1'x8", and had 5 rows of 10 numbered red buttons on the top, with a meter movement off to the right. Translucent plastic overlays with holes in them went over the buttons; each 50-pin LRU connector had it's own overlay to document the signal (that should be) present on each pin.

Manpower required: When the F-4J was initially introduced, the radar system was a quantum leap over what was previously available - and was a very complex piece of gear. I was told back in the 70's that when Marine squadrons were initially equipped with these aircraft, that Radar Shop was manned by 120 people - to maintain 12 aircraft! :eek: By the time I was trained to maintain these radars, each Radar Shop had about 20 Marines, or about 7 per shift (days, nights, mids/mid crew.)

Not much maintenance got done during the day; that's when the aircrew flew their sorties. Change a fuse, pressurize the Coolanol-25 (a very thin oil used for cooling, sort of like WD-40, VERY expensive at around $80/gallon in 1980) or something else simple. De-briefed aircrews returning from sorties, perhaps began troubleshooting failures.

Night crew was tasked with getting nearly everything fixed - if they ran into a really tough problem, that would be left for mids. But if there were more than a couple of aircraft left to fix by the time mid crew came in, it would not be a pleasant situation.

Mid crew was the "tiger team" - they would fix the really tough problems. Sometimes, these were buried deep in the wire harness, and many panels would need to be taken off of the aircraft. I really liked working mid crew.
 

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OK, now I'm really stretching my memory.

There were a number of versions of the AWG-10 radar. The versions I worked on were 1472 (AWG-10, later edition) and 1527 (AWG-10A). There were various changes between the versions, obviously. It looks to me like you found drawings from an earlier version than I worked on.

I'll attempt to address each image in order.
AWG10a.jpg
MAN VEL - I don't recall this control being present. It likely would've only been used in PD mode.
Vc LOW/HIGH - not present in 1472/1527. It would have manually changed the Closing Velocity (range rate) envelope.
SCAN - Funny I'd completely forgotten this control. We'd leave it in 3-bar scan during ground testing. SS would simply scan left and right, no elevation change (except for RIO's thumbwheel input)

AZ - this would control the X-azimuth scan of the radar; normally left in "wide" mode for a 120 degree scan. BST would force the antenna to "boresight", or aligned along the aircraft's centerline.

MSL GATE - Missile gate. If the aircrew wanted to take a chance, they could select "wide" which would allow the firing of a missile outside of the computer-plotted kill envelope. This could be a very valid tactic, such as scaring a bogie off the tail of a wingman.

VEL COV CTR - used in PD mode. Sort of like scrolling up and down this page, you could use this switch to scroll in three steps up and down the frequency spectrum.

ANT - Sometimes, the inertial nav gyros would fail. When they did, you'd select GYRO OUT to disable that input to the radar. The artificial horizon line on the scope would then remain fixed from left to right across the screen.

ERASE CLUTTER - this was a pushbutton, not a toggle switch in later models. The screen had a lot of persistence. The ERASE CLUTTER button was equivalent to CLS on a PC - just get rid of all of the persistent stuff to prepare for a fresh "paint" of the screen.

FUNCTION - Same modes as I remember. You'd have to put it into OPR in order to enable the transmitter - but there was a weight-on-wheels switch on the starboard landing gear which would prevent radiating RF on the ground (unless you manually jumpered across it or some such.) You'd have to push the switch in and rotate it to select EMERgency mode, which would deploy the tell-tale red flag below the switch. Had a RIO scratch most of the red paint off the flag trying to get it to go back up ;)

MODE - PD (Pulse Doppler), PULSE (both Short Pulse and Chirp modes) VI (Vis Ident, never used) H MAP / L MAP (the PPI modes) A-G (the antenna was locked in boresite in this mode) TERR (Terrain Clearance mode; X'd out)

AWG10b.jpg
The BIT box buttons!
The visual readout looked only vaguely like what is represented. Each frame had a test number in the top of the readout, and near the bottom, where the next tests were if failure or success occurred.

You could manually scan forwards/backwards through the tape, and select a random test if you desired.

You could press GO to force a "go" condition even if a test frame failed.
If a frame failed, the tape would stop, and the "NO-GO-FI" button would illuminate. Pressing the NO-GO-FI" would attempt a logical Fault Isolate to discover the area of the problem. It wasn't all that accurate.

The thumbwheel switch controlled the brightness of the buttons and readout.

AWG10c.jpg
Top image: this is a display of PD mode. Note the "main beam clutter" - this is the upside-down notch I was talking about; the clutter return from the ground. Since the notch is relatively flat, the speed of the aircraft is currently pretty low. See the "6" on the right? The tic mark is the antenna elevation strobe. The "blips" near the bottom of the screen are near Fo, or the frequency of the radar, which means their Vc, or speed relative to the aircraft, is near zero. The blips near the top of the screen are closing at a very high rate, perhaps 1,500 knots or better.

Center image: RIO has initiated half-action on his control stick. Radar is switching PRF rapidly, the antenna feedhorn is nutating at a 66hz rate, and the antenna is slaved to the RIO's stick. RIO controls antennas' azimuth by moving his stick left and right, and the range gate by moving the stick forward and aft. Elevation is still controlled by the thumbwheel.

Bottom image: Much is self-explanatory. Steering error dot - the direction the pilot should fly to get a better "bead" on the target, or improve the chances of hitting the target with a missile. ASE circle - the steering error dot needed to be inside this circle in order to fire a missile. As the aircraft neared the target, the circle would become quite wide, but beyond a certain point it would get much smaller again. It represented the kill envelope of the missile. RANGE RATE CIRCLE - you would find the RANGE RATE GAP to determine the Vc of the target. The range rate gap was usually 1/8" to 1/4" wide, but in this drawing you can't see it at all! The gap would rotate around from about the 1 o'clock position to roughly the 11 o'clock position. I don't recall offhand what Vc's the positions meant (27 years, remember?) but in most of the BIT tests, the Vc gap would be in about the 7:30 position.

That's enough racking my brain for the moment.
 

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The document they are from is an official report into the AWG-10 from 1967, probably connected with UK Phantom II acquisitions.

Paul.
 

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AWG10d.jpg - don't feel like commenting on this one at the moment, as this is not quite the same as the 1472 or 1527 mods looked like.

AWG10e.jpg
Pulse mode - basically, the same display for all pulse modes (whether Short Pulse or Chirp; the aircrew wouldn't need to be aware of the electronics involved.)

Top image: pulse scan mode. Note that the vertical line is labeled "B-SWEEP". This was the way the scope was swept for ACM; vertically rather than in a radial scan. This kept the display pretty evenly lit from top to bottom. Were it a PPI-type scan, it would've required constant fiddling with the brightness and contrast controls to detect close vs far away targets. The acq symbol was always present on the screen.

Center image: RIO is in half-action, ACQ SYM over target, ANT slaved to RIO's stick, feedhorn nutating @ 66Hz causing the dithering.

Lower image: Tracking. I don't recall the "contracted position of range rate circle" being present on our later systems. Basically, the information presented by that circle is redundant to the outer range rate circle, and clutters up the display - likely why it was removed. This same comment would apply to AWG10d.jpg.


AWG10f.jpg
Pretty much what I remember, except for 4) Bombing Range Strobe - don't believe our radars had them. We didn't spend much time testing in PPI mode. If our aircrew were going to drop bombs, they tended to use the gunsight instead.

AWG10g.jpg
What you see is what we got - not much information there, eh? About the best you could hope for would be a large return from a building, which you could lock on to - then you would be given the range to the target.

AWG10h.jpg
Terrain Clearance mode - guaranteed to turn your shiny Phantom into a smoking hole in the ground.
All 1472 and 1527 models I worked on were modified to the lower display.

AWG10i.jpg
VIS-IDENT mode display - hmm, this actually could've been the RIO's way of selecting VTAS for the pilot. I just don't remember; I didn't work on VTAS-equipped Phantoms for very long, and that was many years ago.

I've already explained the basics of acquiring the target using VTAS - but looking at this diagram, when the pilot went to half-action on his stick button, the range gate would sweep out from the bottom up to the target, and select the closest target on the pilot's visual az/el

That about covers it, well - what I can remember anyway.

Hope this helps...
 

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Well, that was really useful, as my document is dry technical stuff like frequencies, PRFs and the like, while your comments actually make sense. Thanks!

Paul.
 

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Points of interest

  • Report written after writer spent a month at Westinghouse for familiarisation prior to setting up facilities at Ferranti.
  • AN/AWG-10 greatly improved capabilities over previous systems
  • Target detection by pulse radar, or pulse doppler. Chirp/evaluation monopulse detection techniques.
  • In pulse doppler mode, targets are tracked in velocity, and range to target determined by auxiliary circuits. Mode used to discriminate target from clutter on the basis of velocity, improving downlook capability. Also very high average power (1KW) which increases range.
  • Normal pulse radar modes are present for short ranges but peak power is limited by the use of a klystron amplifier essential to pulse doppler operation. Pulse expansion and compression techniques (chirp) are used to achieve higher duty ratio and high effective power short pulses.
  • Elevation monopulse used for terrain clearance mode, which gives steering indications to avoid terrain obstacles in low level flight.
  • Monopulse also used in air to ground ranging mode.
  • In pulse doppler mode the antenna will update velocity by nodding to pick up ground returns, to improve navigational accuracy
  • Low altitude operation used for weather mapping and mapping from low altitudes using pencil beam
  • Beam spoiler used for better map presentation at high altitudes.
  • Two displays, for pilot and navigator. Lights used for mode & informational presentation, plus direct view greyscale radar displays.
  • 3 computers located behind RIO, to provide missiles with target data
  • CW transmitter for Sparrow illumination
  • Extensive Built In Test facilities

Thats just the first page.
 

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  • Uses solid state circuits to save space.
  • Packaged in LRUs for flight line replacement with few or no harmonisation adjustment required.(really??? - Overscan)
  • Most units in the nose behind the radome, in a structure with slides forward for easy access.
  • Indicator and optical sight in pilots cockpit. All controlling units in the radar operators cockpit. Three computers located aft of the operator's cockpit, above fuel cells.
  • Antenna AS1906 contains waveguide feed to a hybrid T which splits the transmitter energy equally between the two halves of a dual waveguide horn. The horn provides an elevation monopulse radiation pattern which is sharply focussed by a 32" paraboloid reflector. For reception, input to two channels are taken from the sun and difference arms of the hybrid T. The difference arm of the T is connected to a waveguide switch to permit selection of the difference signal or the input from an auxilliary waveguide horn located at the rime of the reflector. The selected signal is appiled to the receiever auxilliary channel. Signals from the sum arm of the T are duplexed part of the transmitter waveguide to the main channel receiver. Low power waveguide (not carrying transmitter energy) is half height to save space and weight.
  • Transmitter and microwave components are located on the right side of the radar assembly mounted in the nose of the aircraft. Power supply and transmitter pulse amplifier are housed in a pressure vessel, which has an air to liquid heat exchanger in its walls. Liquid coolant is pumped through the walls to cool the air, which is then used to cool the several units.
  • Transmitter Pulse Amplifier is commonly called the Pulser and is one of the units located in the pressure vessel. This LRU applies high voltage to the pulse transmitter power klystron during transmit interval and removes high voltages during receive intervals as determined by pulses produced in a timer antenna unit.
  • Radio Frequency Oscillator is an LRU mounted beneath the after part of the transmitter pressure vessel. It provides the system with very stable pulse transmitter and first mixer (local oscillator) frequencies. Since it also generates a CW transmiter frequency in another unit, this unit is the source of all microwave frequency used in the system except the parametric amplifier pump signal.
 

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OK, his comments need some "commenting up". I'll have to attack that later on, as it's 11:50 PM here in Florida, and I have a rather busy day tomorrow.

Yes, Paul - I try to make comments in layman's terms, as many folks who wish to have a basic understanding of the system just wouldn't get it if I went overboard into dry technical jargoneze - and that would defeat the entire purpose of my post! The material you're reading is more targeted towards someone whom already has a rather technical background.

OK, I really have to hit the sack! Goodnight!
 

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A little more on "chirp" mode:
When I first explained it above, I said that the 0.65 uSec pulse hit the delay line and "rang" it like a bell. That's not precisely what happened.

A bell, when struck, usually produces the same tone from when first struck until the oscillations/vibrations cease.

The delay line, when hit with the pulse, "rings" with a range of frequencies, starting quite high and rapidly decreasing, sort of like running your finger down a piano keyboard, or up a guitar's frets. This frequency shift was mixed in with the radar's Fo (Frequency Of the oscillator, or the Klystron frequency) and sent out towards the target.

When the reflected energy came back, the same frequency shift was still riding on the Fo, and was sent back through the same delay line. However, the higher frequencies were delayed more than the lower frequencies. That's why the compression scheme worked.

Average power:
The main KPA was rated at 1,525 Watts. I don't know how they came up with a 1KW average power rating, when the duty cycle was somewhat less than 50% even in PD mode. The most it could possibly put out in PD mode would be closer to 750 Watts. Perhaps they gave the CW illuminator KPA's average power by mistake.
 

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  • overscan said:
    Report written after writer spent a month at Westinghouse for familiarisation prior to setting up facilities at Ferranti.
One month isn't a lot of time to spend FAMming a system of this complexity. I lived with that system for over four years, plus over a year in training. However, that author wrote his comments immediately after his FAM period; and I last touched one in March of 1980, or roughly 27 years ago.
AN/AWG-10 greatly improved capabilities over previous systems
Writer obviously knew nothing of the YF12A. ;) Actually, he was probably referring to the F-4B's radar. And yes, the F-4J's radar was a great deal more sophisticated than the F-4B's radar.
Target detection by pulse radar, or pulse doppler. Chirp/evaluation monopulse detection techniques.
The evaluation monopulse is the "short pulse" 10nm mode I spoke of previously, 0.65 uSEC pulse.
In pulse doppler mode, targets are tracked in velocity, and range to target determined by auxiliary circuits. Mode used to discriminate target from clutter on the basis of velocity, improving downlook capability. Also very high average power (1KW) which increases range.
First portion, basically what I'd said. The ground clutter notch is what improved the downlook capability, but any target with the same velocity as groundspeed would fall into that notch and be invisible to the radar. The F14 Tomcat got around that with digital signal processing.
Normal pulse radar modes are present for short ranges but peak power is limited by the use of a klystron amplifier essential to pulse doppler operation. Pulse expansion and compression techniques (chirp) are used to achieve higher duty ratio and high effective power short pulses
Peak power is ALWAYS limited! And no, a Klystron Power Amplifier (KPA) isn't essential to PD operation; the Tomcat did quite nicely with a 10kw TWT [Travelling Wave Tube], thanyouverymuch. Actually, I think he's working on the KPA vs Magnetron angle - and no, a Magnetron wouldn't work for a PD radar. Chirp pulse expansion/compression technique already explained.)
Elevation monopulse used for terrain clearance mode, which gives steering indications to avoid terrain obstacles in low level flight.
Terrain clearance mode = smoking hole in the ground, display "X"ed out in later versions.
Monopulse also used in air to ground ranging mode.
Yep!.
In pulse doppler mode the antenna will update velocity by nodding to pick up ground returns, to improve navigational accuracy
This is a new one on me. The radar had inputs from various navigational instruments, including ground speed; the ground speed input was used for creating the ground clutter notch
Low altitude operation used for weather mapping and mapping from low altitudes using pencil beam
I don't remember this mode.
Beam spoiler used for better map presentation at high altitudes.
This is the PPI/Map mode I remember. Beam spoiler would pop out about an inch to 1 1/2 inches. Resulting beam would be narrow, but "tall" - rather like a straw broom turned sideways.
Two displays, for pilot and navigator. Lights used for mode & informational presentation, plus direct view greyscale radar displays.
I have no clue what these "direct view greyscale radar displays" are that he's talking about. Whatever they were, neither the 1472 nor 1527 mods had them. The displays had an interesting feature; a black-anodized aluminum ring with a tab on it that had a polarized film lens mounted in it; when rotated, the display would change from it's normal green glow to a red glow, to reduce the possibility of blinding the aircrew at night.
3 computers located behind RIO, to provide missiles with target data
LRU's 15, 16, and 17. These analog computers contained a slew of servos and resolvers. In the 1572 mod, these analog computers were eliminated and replaced by LRU 15 and 16 which were all digital. Two interestingly-named signals provided to the missiles were "HEAD AIM", telling the missile where to aim the seeker head, and "ENGLISH BIAS", or how far to offset the seeker head from the head aim signal. When the missile came off the rack, it would rotate approximately 45 degrees. The combination of the HEAD AIM and ENGLISH BIAS signals would result in the seeker head pointing at the target after the rotation.
CW transmitter for Sparrow illumination
Yep - and if the radar broke lock before the missile detonated, the missile would "go stupid", or impact the ground without detonating.
Extensive Built In Test facilities
Annoying Built-In Test Facilities ;)
 

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overscan said:
Uses solid state circuits to save space.
HAH! As I said before, their idea of "solid-state circuits" was to cluster a bunch of discrete components like resistors, capacitors and diodes, and epoxy them all into a rectangular cube (or whatever shape would fit the space left on the board) - the spacing and placement of the leads coming out of these cubes was anything but consistent - absolutely nothing like the DIP's, SIP's and SM devices that have been around for many years now.
Packaged in LRUs for flight line replacement with few or no harmonisation adjustment required. (really??? - Overscan)
This is by and large a true assertion, believe it or not. The big pain in the keister would be if you had to change the frequency of the radar, which I'd basically written up a few years ago, in one of the early replies to this thread - if one replaced "4A3A7" with "4A3A4". For the most part, the adjustments for the aircraft's channel was easily available without removing components/covers, except in the cases of the LRU 2A8 (Receiver), main KPA and CW Illum KPA.
Most units in the nose behind the radome, in a structure with slides forward for easy access.
Except for the Coolanol-25 pump - that thing was a PITA to get out. It was located under the lower package extension rail, which you'd have to disconnect and slide forwards under the package. Then you'd have to drop the 5 and 6 equipment pallets, and actually climb into the nose of the aircraft. This was not fun at all for a guy who's 6'3" tall.
Indicator (scope) and optical sight (gunsight) in pilots cockpit. All controlling units in the radar operators cockpit. Three computers located aft of the operator's cockpit, above fuel cells.
The gunsight was mounted in the LRU-9 (Pilot's scope), on the front of it using four Allen-head screws. Backlighted indicators displayed ranges and modes. The gunsight itself was a heads-up glass plate, mounted in a frame that could be folded flat against the top of the scope, or stood up for use. It's angle was adjusted using a graduated dial on the right side, that was marked in degrees. The gunsight pattern was white light, projected downwards by a bulb mounted on top of the gunsight, reflected off a mirror in the bottom of the sight and up onto the glass plate, then reflected back to the pilot. Intensity of the gunsight pattern was adjustable using a knob on the front of the gunsight. There was a shutter made of rubberized canvas that could be slid across the projector opening, in case too much sunlight was entering the scope making it difficult to see.
Weren't the computers mentioned before? I think the guy is hung up on the computers. ;)
Antenna AS1906 contains waveguide feed to a hybrid T which splits the transmitter energy equally between the two halves of a dual waveguide horn. The horn provides an elevation monopulse radiation pattern which is sharply focussed by a 32" paraboloid reflector. For reception, input to two channels are taken from the sum and difference arms of the hybrid T. The difference arm of the T is connected to a waveguide switch to permit selection of the difference signal or the input from an auxilliary waveguide horn located at the rim of the reflector.
The aux waveguide horn is for the CW illuminator KPA - PERIOD!
The main feedhorn was indeed fed from the hybrid T.
The selected signal is appiled to the receiever auxilliary channel. Signals from the sum arm of the T are duplexed part of the transmitter waveguide to the main channel receiver. Low power waveguide (not carrying transmitter energy) is half height to save space and weight.
There was a good bit of plumbing using semirigid coax and SMA connectors for the low-power stuff. The only waveguide switch that I can remember was on the lower starboard side of the antenna, LRU 1, to switch the transmitter between antenna or dummy load.
Transmitter and microwave components are located on the right side of the radar assembly mounted in the nose of the aircraft. Power supply and transmitter pulse amplifier are housed in a pressure vessel (the hat), which has an air to liquid heat exchanger in its walls. Liquid coolant is pumped through the walls to cool the air, which is then used to cool the several units.
yep - the HVPS's would get pretty doggone warm. The 400hz 3-phase fans would really scream with the top of the hat off.
Transmitter Pulse Amplifier is commonly called the Pulser and is one of the units located in the pressure vessel. This LRU applies high voltage to the pulse transmitter power klystron during transmit interval and removes high voltages during receive intervals as determined by pulses produced in a timer antenna unit.
We never called it the Pulser. More like "wannabe bitchin' ashtray ;)"
Radio Frequency Oscillator is an LRU mounted beneath the after part of the transmitter pressure vessel. It provides the system with very stable pulse transmitter and first mixer (local oscillator) frequencies. Since it also generates a CW transmitter frequency in another unit, this unit is the source of all microwave frequency used in the system except the parametric amplifier pump signal.
We didn't have to mess with the RFO much - it was the most reliable part of the 1472-mod radar. I think I replaced a grand total of ONE of these in four years. I did have to replace an LRU-3 fuse a couple of times.
 

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Tided up your replies to make them clearer. Will post more tonight :)
 

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Receiver Components are mounted on a pallet at the left forward portion of the nose package. Permits unit to be lowered for access when the system is on the intermediate level bench and when the nose package is extended.

A portion of system interconection cables is located within the pallet so LRUS can be easily removed by disconnecting from the cabling.

Intermediate Frequency Amplifier assembly contains nine subassemblies which perform i.f. amplifier functions in both pulse and pulse doppler receivers, in addition to the pulse expansion & compression for chirp operation.

Doppler Spectrum Analyser is the centre unit on the receiver pallet. It contains circuits to separate the signals on the dppler receiver on the basis of frequency, wich relates directly to target velocity relative to the interceptor. Of the 14 assemblies, 10 make up the bank of filters and the associated amplifiers. The remaining units scan the filters and process the resultant video.

Target Data Tracker is the top unit on the receiver pallet. This contains assemblies performing functions in the doppler receiver tracking loops and the several associated local oscillators.

Synchroniser subassemblies are mounted on the centre pallet and consist of a chassis with interconnection cabling between connectors to permit easy access. The synchroniser consists of a range terrain clearance tracker and a timer antenna servo. This LRU operates in the pulse and monopulse modes to provide range computations to target, and performs certain video and a.g.c processing in thesemodes.The timer electrical signals for antenna positioning and generates the missile auxiliary pseudo and simulated doppler signals.

Control Components comprise the scan pattern generator, the top unit on the control pallet, which generates signals to control antenna scanning in any mode or conditions except target tracking and manual control.

Klystron Power Amplifier receives 35mW of RF power from the radar frequency oscillator over a frequency range from 9.6 to 9.9 gigacycles and develops an output of 2 kW. The KPA is gated on and off by the pulser.

The pulse compression ("Chirp") unit generates a wide pulse containing a linear FM carrier signal. It also supplies a narrow pulse to establish a time zero and compensate for the inherent compression delay of the system. This compression unit also compresses the wide received pulses into narrow pulses in order to increase the range resolution of the radar system. The total effect is that the detection rang is dependent on the high average power of the transmitted envelope, but the target resolution is dependent on the width of the compressed pulse.

Low noise amplification of the received microwave signals is provided in both the main and auxiliary channels. This is accomplished by the use of a microwave frequency parametric amplifier, pump klystron, and the necessary associated microwave components. The main characteristics are:

Gain 15-19 dB
Bandwidth 300 megacycles minimum
Noise figure 4.3dB max
 

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The Doppler system consists of IF stages, mixers, filters, and data processing circuits in various configurations to provide useful velocity, range and angle track information. In addition, the PD receiver contributes the necessary inputs to other systems to aid in navigational fire control. The PD system is capable of operating in either a manual control submode or in one of three automatic submodes.

The BIT programme controls all built in test functions of the radar. It may be operated manually or automatically. A read out window provides written instructions to the operator as required to complete a particular test and indicates the LRU to which a fault has been isolated. All faults are visually indicated by degraded & no-go lights. The BIT fitted with a suitably programmed tape actuates 28v d.c. commands to the radar set BIT relays and measures voltage outputs where required. It als provides visual read-outs to the radar operator in order to verify that the radar system is operational or, if ot, to isolate faults.

Electrical Equipment Rack is the central structure of the nose package of the radar. Included are the pallet structures on which units are mounted, the liquid to air heat exchanger in the walls of the transmitterhousing and the interconnectng cable harness. Cooling air and liquid coolant are conveyed through the rack to the points of use. The rack and the components mounted on it may be extended from the nose of the aircraft on to a piece of ground equipment for easier access.

Command indicator unit is located in the forward cockpit beneath the windscreen. An optical sight is provided as part of the indicator to project a reticle at infinity so that the aircraft can be aimed at a target (e.g, ground attack). The indicator included a storage tube with associated circuits mounted either side of the tube.

The radar Indicator is located in the after cockpi for use by the radar operator. This uit lacks the optical sight but has the same assemblies as the command indicator but arranged in a different mechanical manner.

The indicator control is located on the left side of the aft cockpit. Functionally this unit generates the various symbols displayed on the indicators and time shares them to produce the composite video signals tothe deflection amplifiers in the indicators.

The radar set control unit is located in the aft cockpit. The radar operator used the radar set control to select the modes, scans, and conditions of operation of the system. Also the receiver gain controls are located in this unit.

The antenna control unit is located in the aft cockpit in a position convenient to the radar operator. The primary function in this unit is the radar control stick, mounted in a ball and socket support, and coupled so that lateral and fore and aft movemens of the stick change the settings of the two variable resistors. These positions represent settings of azimuth and range or veocity when the system is under manual control. The action switch is a spring loaded three position push switch. When pressed to the first indent, called half action (HA), the antenna and tracking loops are placed under operator control. The second indent (Full Action, FA) position commands the system to attempt lockon to a target selected by the radar operator. There is a further thumb-wheel control which sets in the manual elevation commands.
 

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overscan said:
Receiver Components are mounted on a pallet at the left forward portion of the nose package.
Well, this is not entirely correct. The receiver, as I knew it, was LRU 2A8, which was mounted underneath "the hat" on the starboard side, and below the KPA's. In order to remove the receiver, you'd have to disconnect a couple of waveguides on the starboard side forward and aft, several coax cables on the bottom, and four Philips-head screws that were threaded into the bottom of the hat, and were a PITA to get to.
Permits unit to be lowered for access when the system is on the intermediate level bench and when the nose package is extended.
OK, a good bit of the processing was performed in LRU's 4 and 5 (already mentioned above) - but we didn't call those the receiver.

A portion of system interconection cables is located within the pallet so LRUs can be easily removed by disconnecting from the cabling.
Yep. The connectors were variously-sized twist-off mil-spec, but we seldom removed the 4A1, 4A3 or 5A1 as an entire unit. The 4A2, 5A2 and 5A3 were generally removed as an entire LRU though.

Intermediate Frequency Amplifier assembly contains nine subassemblies which perform i.f. amplifier functions in both pulse and pulse doppler receivers, in addition to the pulse expansion & compression for chirp operation.
Now he's talking about the different boards, like the 4A3A4 was a part of that.

Doppler Spectrum Analyzer is the center unit on the receiver pallet. It contains circuits to separate the signals on the doppler receiver on the basis of frequency, which relates directly to target velocity relative to the interceptor. Of the 14 assemblies, 10 make up the bank of filters and the associated amplifiers. The remaining units scan the filters and process the resultant video.
Seems to me that there were 290 crystal filters in ovens inside of LRU-4A2, each tuned to a slightly different frequency. Each filter represented a "slot" in the frequency spectrum that is displayed on the screen. The higher the frequency above Fo, the higher it's painted on the screen. That's why PD mode wasn't an intuitive display - people are used to seeing things in terms of distance and vector from straight-ahead - which is what short pulse, chirp and MAP modes displayed.

Target Data Tracker is the top unit on the receiver pallet. This contains assemblies performing functions in the doppler receiver tracking loops and the several associated local oscillators.
Yeah, and if the Zener diodes in the 4A1A7 got fried, it would get "stuck" in 60ms PRF switching and wouldn't lock on.

Synchronizer subassemblies are mounted on the center pallet and consist of a chassis with interconnection cabling between connectors to permit easy access. The synchronizer consists of a range terrain clearance tracker and a timer antenna servo. This LRU operates in the pulse and monopulse modes to provide range computations to target, and performs certain video and a.g.c processing in these modes. The timer electrical signals for antenna positioning and generates the missile auxiliary pseudo and simulated doppler signals.
5A1 through 5A3.

Control Components comprise the scan pattern generator, the top unit on the control pallet, which generates signals to control antenna scanning in any mode or conditions except target tracking and manual control.
6A1.

Klystron Power Amplifier receives 35mW of RF power from the radar frequency oscillator over a frequency range from 9.6 to 9.9 gigacycles and develops an output of 2 kW. The KPA is gated on and off by the pulser.
I guess I'll be typing 1,525 watts until my fingers fall off. ;)

The pulse compression ("Chirp") unit generates a wide pulse containing a linear FM carrier signal. It also supplies a narrow pulse to establish a time zero and compensate for the inherent compression delay of the system. This compression unit also compresses the wide received pulses into narrow pulses in order to increase the range resolution of the radar system. The total effect is that the detection range is dependent on the high average power of the transmitted envelope, but the target resolution is dependent on the width of the compressed pulse.
Well, he got some of it right. Both short pulse and chirp were triggered by a 0.65 uSec pulse; however in Chirp mode, the 0.65 uSec pulse was run through the delay line (basically just a coil that was grounded at one end) resulting in the transmitter firing for about 65 uSec. The received pulse was run back through that same exact delay line for pulse compression. It wasn't perfect; the compressed pulse was 0.8 uSec wide - but it was a heck of a lot stronger than the return from short pulse would've been. Best resolution was somewhere around 150-200 feet - but when you're lobbing a missile at someone, that's close enough ;)

Low noise amplification of the received microwave signals is provided in both the main and auxiliary channels. This is accomplished by the use of a microwave frequency parametric amplifier, pump klystron, and the necessary associated microwave components.
All in the 2A8.
The main characteristics are:

Gain 15-19 dB
Bandwidth 300 megacycles minimum
Noise figure 4.3dB max
I just had to change some Kings' English to American English. Sorry old chaps - I wish you Brits would learn how to spell ;)
 

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Oh, I suppose you want me to comment all THAT crap too, eh? ;)

Well, mebbe later. I have to actually get something useful done first ;)
 

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I'm going to skip ahead to the tech specs section next. Theres pages of this stuff :)
 

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overscan said:
The Doppler system consists of IF stages, mixers, filters, and data processing circuits in various configurations to provide useful velocity, range and angle track information. In addition, the PD receiver contributes the necessary inputs to other systems to aid in navigational fire control. The PD system is capable of operating in either a manual control submode or in one of three automatic submodes.
Is the coffee ready yet?

The BIT program controls all built in test functions of the radar.
Well, Duh!
It may be operated manually or automatically.
Yep.
A read out window provides written instructions to the operator as required to complete a particular test and indicates the LRU to which a fault has been isolated. All faults are visually indicated by degraded & no-go lights. The BIT fitted with a suitably programmed tape actuates 28v d.c. commands to the radar set BIT relays and measures voltage outputs where required. It als provides visual read-outs to the radar operator in order to verify that the radar system is operational or, if not, to isolate faults.
The "programmed tape" was actually a long strip of black & white film like what was used in movie cameras. I think it was 35mm film? After a fair period of use, the film would get rather worn, and this would cause the areas which programmed the BIT relay tree to wear thin, and allow too much light to leak through the tape, tripping relays that shouldn't have been tripped for a particular test. The IMA (Intermediate Maintenance Activity) radar techs would have to open up the box, pull out the film, and repair the scratches. Sometimes they used black magic markers, and I even saw one tech using a product called "EM-NU", which was used for touching up metal chevrons' flat black finish.

Electrical Equipment Rack is the central structure of the nose package of the radar. Included are the pallet structures on which units are mounted, the liquid to air heat exchanger in the walls of the transmitter housing and the interconnectng cable harness. Cooling air and liquid coolant are conveyed through the rack to the points of use. The rack and the components mounted on it may be extended from the nose of the aircraft on to a piece of ground equipment for easier access.
The Coolanol-25 was fed to the package via the umbilical catenary. Cooling air was fed via a collapsible metal tube, perhaps 1 1/4" diameter, located near the bottom aft portion of the package. Thinking about this reminded me of the "kidney" - it was a brown kidney-shaped fiberglass plenum assembly that was back against the firewall; it re-routed the cooling air that was coming forward from either the cooling air access panel in the nose wheelwell (port side) or the a/c system.

Command indicator unit is located in the forward cockpit beneath the windscreen. An optical sight is provided as part of the indicator to project a reticle at infinity so that the aircraft can be aimed at a target (e.g, ground attack). The indicator included a storage tube with associated circuits mounted either side of the tube.
We always called the optical sight a "gunsight" - in retrospect, this was a ridiculous name for it, as neither the F-4J nor the F-4S had guns! Yes, a MK-IV gun pod could be fitted on the centerline tank mount, BUT - the Phantom's GE-J79 engines were thirsty beasties gulping up all the fuel that could be fed to them - in full A/B on internal stores it would run out of fuel in 18 minutes - and during ACM, the first thing the pilot would do is punch off (jettison) external stores, which would include the gun pod. :-\ The idea of firing missiles at a standoff range of several miles was quite attractive, but when the ROE's dictated positive visual ID, that advantage went away - so the aircrews were stuck in dogfights with no guns; and basically inside the effective range of the Sparrow missiles. Not a happy situation for our guys.

The Radar Indicator is located in the after cockpit for use by the radar operator. (RIO) This unit lacks the optical sight but has the same assemblies as the command indicator but arranged in a different mechanical manner.
The Pilot's scope, LRU-9, was in a fixed mount, secured by two safety-wired bolts, one on either side. The pilot needed to ensure that the safety wire was present, particularly on carrier launches; as if the bolts were missing, the pilot's scope would come crashing back into his face. The RIO's scope (LRU-11) was in a retractable mount that had at least three positions that I remember; fully retracted (down and forward), 1/2 up (for short RIO's) and full up. The mount had S-shaped channels for the scope guides, so as it was pulled up vertically, it inclined rearward. It was necessary for the scope to retract forward in a vertical position, as otherwise during ejection the RIO's legs would be torn off. The RIO's joystick (LRU-12) was mounted on the partition, above and to the right (starboard) of the scope, and it would also retract upon ejection, or manual selection.

The indicator control is located on the left side of the aft cockpit. Functionally this unit generates the various symbols displayed on the indicators and time shares them to produce the composite video signals to the deflection amplifiers in the indicators.
This is LRU-10, the ICU, which I'd mentioned before. A black box, perhaps two feet long, 10" tall by 10" deep. The front (RIO's side) cover was removeable by twisting a large number of captured screws 90º to expose the control boards. Nearly all of the onscreen symbols and their positions could be "tweaked". As a matter of fact, we had one RIO who liked to custom-tweak his displays. ::) The 2nd time he did that, we took his screwdriver away and threatened to break his fingers if he did it again. ;) The LRU-10 was held in by four bolts; two very easily accessible right below the canopy rail, and two more underneath that were an absolute PITA to get out. There were several of the typical MIL-spec connectors on the bottom of the unit, and one unusual connector that was made by Hughes - it had 23 RG-58 coaxial cable connections in it, and was capable of 25 coax connections. If the coaxes needed repair, woe be you. This was not a fun task.

The radar set control unit is located in the aft cockpit. The radar operator used the radar set control to select the modes, scans, and conditions of operation of the system. Also the receiver gain controls are located in this unit.
LRU-13 or LRU-14? I don't remember - we didn't replace many of them. They were mounted on the partition, to the upper left of the scope (port side). It was in a mount hinged at the top, with a release lever on the bottom - it would retract a whole 1 1/2" or so, to get out of the way during ejections.

The antenna control unit is located in the aft cockpit in a position convenient to the radar operator. The primary function in this unit is the radar control stick, mounted in a ball and socket support, and coupled so that lateral and fore and aft movemens of the stick change the settings of the two variable resistors. These positions represent settings of azimuth and range or veocity when the system is under manual control. The action switch is a spring loaded three position push switch. When pressed to the first indent, called half action (HA), the antenna and tracking loops are placed under operator control. The second indent (Full Action, FA) position commands the system to attempt lockon to a target selected by the radar operator. There is a further thumb-wheel control which sets in the manual elevation commands.
In retrospect, the way the RIO's joystick was set up was kind of goofy. Having the antennas' AZ slaved to the port/starboard slewing of the stick made perfect sense, but up/down being controlled by the thumbwheel must've been hell for the RIO's, particularly during ACM. Seems to me it would've made a lot more sense for elevation to have been controlled by forward/aft movement of the joystick, with sensitivity being controlled by the thumbwheel, and just use the radar's electronics to sweep out the range gate (or velocity for PD) to acquire a target. It would take quite a few cranks on that thumbwheel to get the antenna against the upper or lower stops.
 

SgtWookie

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overscan said:
I'm going to skip ahead to the tech specs section next. Theres pages of this stuff :)
Oh, joy. ::) ;)
Valiant Air Command near Titusville, FL has a Navy F-4J Phantom in it's inventory - it's about a half-hour's drive from me. They pulled off the antenna and put it inside the museum. Perhaps I'll have to take my radar tech's tool pouch over there some day and go exploring ;)
 

overscan

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AN/APG-60 (AWG-10) Specs (UK version I think?)

Radar provides following information

1) Target relative bearing
2) Target range
3) Closing velocity
4) Attack info for missiles
5) Radar Ground map
6) Steering Info for Terrain Clearance

Frequency Characteristics: 9,600 - 9,900 Mc/s and simultaneously 10,050 -10,250 Mc/s (main + CW)

Peak RF power delivered to antenna is between 1 -2.6 kW with a nominal value of 1.65 kWfor search or track conditions using the pulse widths and pulse repetition frequencies specified below over 9,600-9,900 M/c

PRFs - PD Mode
300,266 +-15pps
300,830 +-15pps
301,614 +-15pps
303,320 +-15pps
309,609 +-15pps

Pulse Modes
During opertion in the Pulse & Map modes the following PRFs jittered a nominal +-10% are used in the ranges listed.

10 miles - 50 miles : 1000pps
100 miles - 600pps
200 miles - 300pps

During TERR & A-G modes PRF is 3000 pps (jittered a nominal +-10%)
In V.I. mode the PRF is 1000 pps (jittered 10%)

Pulsewidths

PD Mode 1.45 +- 0.1 microsec

Pulse Modes
Pulse: 40 microsec (except 0.65 microsec in 10 mile range
HI MAP 40 microsec
LO MAP 40 microsec (except 0.65 microsecin 10 & 25 mile range)
TERR 0.20 microsec +- 0.07 microsec monopulse
A-G 0.20 microsec +- 0.07 microsec monopulse
VIS. IDENT 0.65 microsec +-0. microsec

Long pulse is transmitted as a 40 microsec pulse, linearly, frequency modulated by the pulse expansio circuits.

Radar TX has fllowing modulation characteristics

a) FM ranging - frequency modulated at 85 cps +-0.25% with a deviation of 2Kc +- 3% when tracking in a PD mode.
b) Spurious Modulation - transmitter undesired sidebands are at least 70dB beow carrier level from 1750 cps to 135 Kc.

CW Illumination
a) Average CW power to antenna is between 123-350 watts with a nominal value of 200 watts: within the frequency band 10,050-10,250 Mc/s

Modulation

CW modulation has the following charateristics

i) Coding. FM at a 310 +- 0.25K/c rate. 0.22 +- 30% modulation index as a coding signal to identify the illuminating source for the AIM-7E missiles.
ii) Range Re-cycle. The CW RF Carrier is FM modulated at an 85 +- 2.0 cps rate. 10K/c +- 30% deviation or 5 K/c +- 30% deviation depending on the type of missile in use. This signal is used as the range re-cycle information for the CW target seeker.
iii) Re-cycle Reference. The coding signal (i) above is amplitude modulatd 20% +- 3% at an 85 cps rate, and lags the range re-cycle signal (ii) above by 90 deg +- 15 deg. This signal is used as a re-cycle reference signal for the CW target seeker.

RX Noise Figure

The overall noise figue measured at the input to the waveguide assembly is not greater than 7.5dB over 9600-9900 M/c and will nominally be 6.0 dB

Antenna Gain

a) AI Modes: 35 dB over the frequency range 9600-9900M/c compared to an isotropic radiator. Adjacent sidelobes are at least 21 dB beow the amplitude of the main lobe.

Auxiliary channel antenna gain at least 15.5 dB. For reception in the TERR mode the sum channel has the same characteristics, and the difference channel has a gain of at least 28.4 dB.

b) Map Modes: Antenna beam is spoiled in elevation to provide Cos squared pattern.

c) CW Illumination Mode: At a frequency of 10,125 +- M/cs the sidelobe levl is higher than -6dB within 10 deg of boresight and higher than 12dB at angles from 10 deg to 35 deg from boresight.
 

overscan

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a) Search Displays

(i) PD Mode - VEL and AA submodes
Vertical axis velocity and horizontal axis azimuth. Symbols: Horizon Line, Elevation Strobe, Acquisition Symbol, Velocity Target Symbol.

(ii) PD Mode - PR submode
Vertical axis range and horizontal displacement azimuth. Symbols: Horizon Line, Elevation Strobe, Acquisition Symbol, Range Target Symbol.

(iii) Pulse Mode
Vertical axis range and horizontal displacement azimuth. Symbols: Horizon Line, Elevation Strobe, Acquisition Symbol, Target Video

(iv) HI MAP / LO MAP
Offset centre PPI display, having radial distance from indicator baseline centre proportional to range, and angular position proportional to azimuth position. Symbols: Horizon Line, Elevation Strobe, Target Video. Additionally shows Lateral Offset Cursor and Bombing Range Strobe at 10 and 25 mile ranges.

(v) A.G. Mode
Stationary horizontal position having vertical displacement proportional to range. Symbols: Horizon Line, Elevation Strobe, Range Strobe, Target Video.

(vi) TERR Mode
Offset centre PPI display. Symbols: Horizon Line, Elevation Strobe, Target Video, TERR Intensification

(vii) VI Mode
Range vs azimuth display. Symbols: Horizon Line, Elevation Strobe, Acqusition Symbol, Target Video.

b) Acquisition Displays

i) PD Mode - VEL Submode: scan stopped at the target selected by acquisition symbol.
ii) PD Mode - AA Submode: scan stopped at the target selected automatically.
iii) PD Mode - PR Submode: as a) i) above
iv) Pulse Modes - range versus azimuth B type with the scan stopped at the target selected by the acquisition symbol.
v) HI/LO MAP modes - PPI display with scan stopped as an angle commanded by the lateral position of control antenna.
vi) Range versus azimuth B type display with the scan stopped at the targe selected by the acquistion symbol.

c) Track Displays

(i) PD Mode - a range versus azimuth display wit an expanded velocity sweep along the left edge of the display. Adds Allowable Steering Error (ASE) circle, Steering error dot, R min, R a, Range Target Symbol, Range Rate Circle, Range Rate Gap to display.
ii) Pulse, LO MAP HI MAP Modes - a range versus azimuth B type display having dithered sweep with Allowable Steering Error (ASE) circle, R min, R a, Range Target Symbol, Range Rate Circle, Range Rate Gap added to display.
iii) AG Mode - As AG Search display with added range rate circle
iv) J (AOJ only) displays similar to the track displays in the pulse MAP modes with range circle removed.
v) VIS IDENT mode - range versus B type display having dithered sweep, and added symbols for Allowable Steering Error (ASE) circle, Steering error dot, Range Rate Circle, Range Rate Gap, Range Strobe

Performnce Characteristics
Search

i) Wide and orientable narrow scans provided. Either single, two or three bar scan with retraced centre bar. These are stabilised for roll and pitch. An additional scan is provided for TERR mode.
ii) Minumum detectable signal (Pulse Mode) - capable of displaying a -105dBm peak target signal as applied to the antenna terminals.
iii) Minimum detectable signal (PD Mode - AA/PR Submode)
Automatically detects signals of 5dB S/N ratio closing at velocity from 120-1800 knots greater than the host aircraft velocity. This peformance obtained in the presence of an unwanted signal of 65dB S/N ratio at the velocity of the host aircraft (noise in a 550 cps bandwidth)
iv) Minimum Discernable Signal (PD Mode - VEL Submode)
Capable of displaying a -138 dBm target signal for targets closing at velocities from 120-1800 knots geater than the velocity of the host aircraft. This is about 3dB less than the minimum detectable signal of the previous paragraph.

b) Tracking operation
Satisfactory tracking will be accomplished under the following conditions at S/N ratios greater than 6dB.
i) Capable of tracking a target within view angle of 120 deg azimuth & elevation.
ii) Capability of tracking target with angular line of site rate of 15 deg/sec
iii) Capability of tracking targets to at least 50 miles in pulse and 100 miles in Pulse Doppler modes.
iv) Capable of acquiring & tracking a targe closing up to 3190 knots and opening at 290 knots.
 

jojo57

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Hello everybody,

I'm working on a Phantom cockpit for Free Falvon 4, and I would need high res flight manual cockpit drawing. I need to be able to read every writing on the diffenrent panel.

The prefered version is the F-4E, but others are welcome.

PS: I already found some good links on internet, and flight manual cockpit drawing, but they are too small.

Thanks
 

roberto_yeager

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I´m looking for some info about a projected modernization from Northrop for the F-4 Phantom... It was a IRST in front of the cockpit (a la F-102)... it was in the 80's

Thanks in advance...

1Saludo
 

oeno

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HI folks!


I`m glad to join this hi tech club,just keep up with good work.

I`d like to ask a qustion about AN/APQ-120,the picture is from his radar manual.

1.Can someone explane HOJ radar mode?
2.What high jitterd in the PRF column means?



3.What do you think about this comparasion of the AN/APQ-120 and Cапфир-23д-III source ariwar.ru?

 

overscan

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HOJ should be home-on-jam mode for countering ECM.
 

oeno

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HOJ is passive operating mode for missile guidance.It is an essential adjunct for semiactive and active systems to counter noise jamming,but I`m not sure what it has to do with the radar.I think it`s something like Jam Angle Track (JAT) in addition to PDSTT of AWG9 function that can provide range, bearing, and speed information for targets that are utilizing on-board jamming equipment.
 

Blaze1

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Interesting topic :). I didn't realise so much information was avaliable on the F-4's various radars, it makes for very good reading.
 

glmm

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oeno said:
3.What do you think about this comparasion of the AN/APQ-120 and Cапфир-23д-III source ariwar.ru?

According to the info I have available on the Cyrano IV, the data on the chart seems reasonably accurate (don`t know which sources they used). No idea on the results for the APQ-120, but the Sapheer 23 surely was a powerful radar set ofr its age.....
 

Eagle2009

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I feel a bit foolish for having to ask this, but I honestly can't make heads or tails of that chart. Could someone explain it please?
 
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