[Collins] Re: collins 618T-3

[Dr. Gerald N. Johnson, electrical engineer]

400 w PEP SSB takes at least 800 w PEP input to the PA plate. More with
the compact continuous tuning tank circuits in the 618T PA. 100 W
carrier AM is 400 W PEP. That drawer full of 60's vintage TTL logic
takes quite a few watts as do the servo amps and the RF driver section.
28 volts at 35 amps is 980 watts. Marginal at best with little room for
those necessities and the inverter inefficiency. I'd figure on 45 amps
not 35 amps. Or just run it on a pair of well charged batteries and let
the current be supplied as it may.

I had an opportunity to work with that MARS 618T, didn't see that it was
a benefit to my station or the program and let KD6E tackle it. He did
get one on the air, but had to work unreasonably regularly to find and
replace failing flat pack TTL SUHL chips to keep it on the air.

Besides the control cables, one needs the extender cables for each
module and then the extender cards or cable for each subassembly or the
Collins module and subassembly test stands.

73, Jerry, K0CQ, Technical Advisor to the CRA.
-- 
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.