[MRCA] Fwd: Fw: [VHFcontesting] 222MHz tube amplifier help - AM-456A/TRA-19

[Scott Johnson]

I believe this is a PA module from the TRC8/11 series multiplex terminal sets used for point-to-point telephone links.  Second generation (early to mid fifties, perhaps)  The TRA designator is a giveaway that it is part of a bigger system, usually for more than one system.

 

Scott W7SVJ

 

From: MRCA [mailto:mrca-bounces at mailman.qth.net] On Behalf Of Steven Board
Sent: Wednesday, November 25, 2015 8:22 PM
To: mrca <mrca at mailman.qth.net>
Subject: [MRCA] Fwd: Fw: [VHFcontesting] 222MHz tube amplifier help - AM-456A/TRA-19

 

Anyone have any idea what this is and any documentation on it??

Tnx & 73

DE KA1LHZ

---------- Forwarded message ----------
From: Walt Murphy <n2wm at centurylink.net <mailto:n2wm at centurylink.net> >
Date: Sun, Nov 22, 2015 at 9:54 PM
Subject: Fw: [VHFcontesting] 222MHz tube amplifier help - AM-456A/TRA-19
To: Steven Board KA1LHZ <sboard.ka1lhz at gmail.com <mailto:sboard.ka1lhz at gmail.com> >


Please read email below.

       Have you any idea what a AM-456A/TRA-19 is?????

                 If not military could be FAA as they use military type numbers to ID Equipment.

                                73
----- Original Message ----- From: "larry" <zm1267 at gmail.com <mailto:zm1267 at gmail.com> >
To: <VHFcontesting at contesting.com <mailto:VHFcontesting at contesting.com> >
Sent: Sunday, November 22, 2015 9:33 PM
Subject: [VHFcontesting] 222MHz tube amplifier help - AM-456A/TRA-19



  Hello all, I'm trying to resurrect this amplifier I found today at a local antique store. It appears to be for the 222MHz band, and uses a 4CX250 tube. It is currently missing several tubes in the Power Supply section (V101, V102, V103 which look to be the rectifier tubes, and V105 which I'm guessing is maybe the time delay), and I could not locate anything of value on the web as far as schematics go. I took a peek underneath the PS to see if it's been updated with diodes, but there isn't anything extra added. Plus, there are 4 wires connected to V101 - 2 coming from the transformer, and 2 leaving and connected to V102. It appears to have been modified for the Amateur frequencies already or was in the process of being done, and I'm hoping it's on 222. Would someone have any idea what tubes I could use in this old beast, or a conversion article or tips on upgrading old military power supplies to SS? The transformer has a 1500V secondary if that helps any.

It looks like I've found my winter project ;-)

Thanks for your help,
Larry
N1MIW
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