Could anyone please ID this RCA 400W RF amp?

[Opcom]

This is maybe a senior moment, as it's been sitting on a shelf for several years, apparently put aside and then forgotten then buried as more urgent work had to get done.
 
I bought it off ebay and IIRC the seller said its frequwncy range was 54-88MHz. It says "class AB" on the two amplifier boards. I was able to look up "Band I" to find that it is indeed 54-88MHz in the USA (47-68MHz in the EU). Unfortunately, searching hasn't turned up these old part numbers or documents.
I don't know what model of transmitter it's from.

The RCA name plate says:
400 WATT AMPLIFIER
BAND I
MI-563161-1
SERIAL 2386110
CAMDEN, N.J.

Some data on the two main amp boards are:
69893
CODE CC
CLASS AB
3477904-2B
L/P 3729671
MI-563181-1

So basically there's an input splitter made of PCB material, the pair of push pull amps, and a combiner made pf PC board as well. Additionally, a control board and multimeter & switch are at the front. A large power socket, and a row of large pins that apparently take the bias. ground, and other voltages that are needed. There's a huge heat sink on the underside.
Transistors: four 372901-2, and two 3729474-4.

Does anyone know if this might work on 6 meters (even at reduced power), and the correct voltages for it, or has the manual for it, so at least I could test it without frying it?

Thanks in advance,

Patrick

[AG5UM]

Did you get any help with this Patrick ?
I actually like this and would not have been able to walk away from it either. It just cries out to be ramped up and turned on.  Reminds me of so much industrial equipment, when people really tried to make things work. At least it is straight forward and knowing the transistors must give you much insight about necessary parameters, voltages, etc. ?
Anyway, hope you find the info. you need, cool project.
let us know...

[Opcom]

I havent gotten any help yet, but it's only been 3 days. The biggest questions are on the row of pins for its control. I think I saw 32V or 36V for the main power somewhere, but anyway I have not looked up the transistors yet.

[AG5UM]

Well ,
I'm going to have to look up these transistors, etc...I'm wondering about the input power levels, etc. seems the control voltages, etc. would not be too difficult to figure out? It makes you wonder what this was used for and what the rest of it looked like. .........I'm wondering how to drive it with a HT-40 on 6-meters...

Anyway, I think I'll try to look up these transistors...
Good luck with a fun research project.

[AG5UM]

Just a simple on-line search.... claims....?
These transistors are custom or internal RCA part numbers and are not in the standard transistor guides or cross reference, etc....
Likely military or broadcast-grade devices, RF power transistors complimentary pairs for final output, from the 1970's,
the (M1-563161-1) 400 watt Band 1, Amplifier VHF Band 54-88 MHZ
likely used in Military, Public safety or Broadcast communications....
they say...
Original RCA military or Broadcast service data would be required...
But....the RCA solid state databooks (SSD-205C,RF/microwave devices, 1975) may contain similar devices, though not these exact numbers...? May be variants of RCA high power RF transistors from 1970's such as 2N3918, 2N4275, MJE210 but custom....
That's as far as I went so far,  just internet searches ??, but maybe better luck in some of the old databooks, etc..?
I think these will turn out to interesting devices.

[Opcom]

I think so as well. I didn't find data on the transistors but know that RCA built semiconductors for many years (or they may have farmed it out.). I'm not very knowledgeable on solid state VHF amps. I only know enough to be dangerous about the types using ferrite core transistors like at HF.

The pc board combiner and splitter are things I've seen before but not experienced from a technical position. They are so similar in apparance than it seeems the in and out could be 50 Ohms. 50 from the exciter, the unit being the IPA, and some large tube or two for the PA itself.

Is the type of construction of the coils on the PCB likely to be 'wideband' as in television channels of 6 or 7 MHz?

Not clearly shown in the pictures is the large heatsink on the back under theboards. The unit seems as though it would have been mounted vertically to a panel having a hole, with the heatsink going through the hole where there is a chamber or tunel with and airfow. It's easy to envision this unit hanging on a panel of a transmitter. There are two screws and two holes, at the corners of the casing.

I am hoping the model number of the transmitter can be discovered and a manual dug up somewhere. I have not yet gotten as far as exploring themessage boards where TV broadcasters congregate in hopes that someone might have been around long enough to have worked with the transmitter or to have saved a manual for it. Also found here is the unusual DC power connector for the unit The control board inside isn't easy to access but nothing's impossible.

I'm also thinking about driving with a 6 meter transmitter. For initial checks, an Icom IC-706 or Alinco DX-70 have low power and are adjustable down to a fraction of a Watt.

[KD6VXI]

Those stripping are the splitter and combiner.

Basically cophase harnesses.

Quarter wave strip lines.

As such they aren't super wideband.  You can probably cover something like 6 meters but that would mean they would be designed for six meters.

Pretty much the same thing CBers where doing when coupling hurricane 350s together in the late 70s with a pairnof cophase harnesses.

If you loon at the matching circuit like that, they make total sense.  The matching networksnuse 75 ohm stripline.  Since the quarter waves invert impedance as well as provide port isolation, they work great.

--Shane
WP2ASS
Deep in Jamaica this week doing hurricane relief.    Thank GOODNESS for this cold snap....  although being on an island for half a decade, this 65 degrees crap is FREEZING