[Milsurplus] MPN-1 was Power supply ID

[Edward Greeley]

At risk of being a bore on this subject, let me say that the MPN-1 was 
really only TWO radars: the "search" (or ASR) S-band radar, and the 
az-el (or PAR) X-band radar. The PAR radar illuminated both the azimuth 
and elevation antennas alternately, by means of a mechanical rotating 
switching system, in the RF path, that was synchronized with the ACUs 
(angle coupling units) that produced the sweep reference voltages for 
the azimuth and elevation CRT indicators. Kind of klutzy, and a real 
bear to align, but it worked surprisingly well.

Or, one might say that the MPN-1 had FOUR radars, since both the ASR and 
PAR had fully redundant electronic components (channel "A" and channel 
"B"). The idle channel was (supposed to be) maintained in a "hot 
standby" condition in case the active channel failed during a critical 
phase of an A/C landing. The only parts of the system that had no 
redundancy were the antennas.

The MPN-1 was equipped with SCR-522s and SCR-274-N stuff for comms.

The FPN-1(XN-2) was an abortive development project that never saw the 
light of serial production. The MPN-1 never had a third radar dedicated 
to height finding capability.

I was performing DLM (depot level maintenance) on MPN-1s in 1951...

Ed

Jim Whartenby wrote:
> It is actually three radars; search (S-Band), azimuth and elevation
> (both X-band).  Specs for the FPN-1 which is covered by the same manual
> as the MPN-1 are at:
> 
> http://tpub.com/content/radar/TM-11-487C-1/TM-11-487C-10048.htm
> 
> I once worked on comm gear installed in a MPN-13 van.  ARC-3s and
> ARC-27s, three sets each, were used to communicate with aircraft. 
> Funny, I was trained in Ground Radio, so never saw these sets in tech
> school.  But we got by.  Fun in the sun at Mactan AB, RPI; June 1968 -
> December 1969.
> Regards,
> Jim