AN/APS-20E Tri-Band radar

[A_Random_Guy]

I recently came accross this document on the history of radar periscope detection with the interesting claim that the AN/APS-20E, as mounted on the P-2 Neptune had three operating bands. L-Band, S-Band, and X-Band.

Page 212 (10 on the pdf)

The APS-20 operated at L-band, S-band, and X-band had selectable PRFs in each band and had a wide selection of pulse widths in each band.

This is interesting seeing as every other source I've seen on the APS-20 says it operated in S-band including this 1949 radar systems survey though the original source claims the APS-20E to having been deployed around 1953, beyond the purview of the survey.

Frustratingly, the author cites a private message as the source for their claims on the APS-20E. That being said they do make specific claims as to the performance of the radar at each frequency lending credence to their statements.

It was a powerful radar that could radiate up to 1 megawatt in L-band and could detect large surface ships out to over 200 nmi on a good refracting day. A highly-trained operator could distinguish approximate target size, heading, and speed within three or four antenna sweeps on a good day. The S-band was significantly better at discrimination and resolution of targets at a range of 100 to 150 nmi. The X-band was even better at detection ranges of 75 to 100 nmi and was especially effective at detecting low-flying aircraft. But like all of these early radars, the APS-20 was very large, heavy, power-hungry, and operator-intensive and was ineffective at detecting small RCS surface targets such as exposed periscopes and masts.

Does anyone have further information on a multi-band AN/APS-20?