Bump
Does anybody have more info on the avionics especially the FCS and the GCI?
http://www.ausairpower.net/TE-Foxbat-Foxhound-92.html
" The core of the weapon system was a massive 1,100 lb I-band air intercept radar, the Smerch A, designated by NATO as the Foxfire. Designed for high peak power output to burn through jamming by a target's defensive ECM, the Foxfire was a pulse Doppler design with a limited look-down capability, and has been described as comparable in this respect to the AWG-10 carried by later USN F-4s. It is not unreasonable to assume that AWG-10 components retrieved from wreckage in North Vietnam would have been closely examined by the designers of the Foxfire. Western sources credit the Foxfire with a Search/track range of 55/40 NM.
The Communists built the Foxfire with the objective of engaging targets at all altitudes, including the standoff missiles of the period which were larger and flew higher than the later ALCM/GLCM. The Foxfire unlike its Western contemporaries, was built entirely with vacuum tubes, a technology which the Communist block developed to a fine art at a time when Western designers opted for semiconductors. While bulky, maintenance intensive and power hungry, vacuum tubes were relatively insensitive to ambient temperatures and EMP and thus were well matched to the environmental extremes of Siberian winters and central Asian summers.
The Foxfire was tightly integrated with a RSIU-5 VHF datalink, NATO designation Markham, reportedly a solid state design, this datalink carried radar video from a ground based GCI scope to the cockpit CRT display of the Foxbat, and also carried radar video from the Foxfire to the GCI station. During an intercept, the Foxbat pilot could approach his target silently on GCI video, and then light up his radar once in position to launch and guide his missiles. The GCI operator could simultaneously advise the pilot while observing a repeated image of the Foxfire's video.
The Foxfire/Markham system was complemented with, by Communist standards, a comprehensive nav/comm fit, including the RSBN-2 short range nav, the SP-50 Swift Rod ILS and MRP-56P beacon receivers, an R-831 UHF comm, a RSB-70/RPS HF comm with an antenna embedded in the leading edge of the left tail, and an ARK-5 DF set. The customary SRO-2 Odd Rods IFF was complemented by a SOD-57M Air Traffic Control/Selective Identification transponder. A Sirena 3 crystal video radar warning receiver was also fitted, it is considered comparable to the Vietnam era APR-25."