[Milsurplus] Rd: GRT-21/22 (NOT GRT-21/23)

[D C *Mac* Macdonald]

Good morning, Glenn and group.

The 8004890G1 is, as I suspected, the UHF (225-400 MHz)
output stage for the AN/GRT-22 exciter/transmitter.

NSN is 5996-00-252-2759.

NSN for the 8006081G1 VHF module is 5996-00-411-1473.

Remember that these are for AM service. PEP output
at 100% modulation would be 40 Watts!

Also, some of these are in 100% continuously keyed mode.

I would guess that they MIGHT be capable of 50 Watts
output in SSB use.

Operating voltage is 19.5VDC regulated.  AM Modulation
is applied through the ALC mechanism/input.

73 - Mac, K2GKK/5
(Since 30 Nov 53)
Oklahoma City, OK



__________________________________
Date: Sat, 01 May 2010 5:14 PM CDT
Subject: Fw: [Milsurplus] GRT-21/23
From: D C *Mac* Macdonald 
Date: 

Hi, Glenn.

I'm not familiar with that part number, but will try to
remember to research it Monday when I go back to work.

I overhaul probably 20 or more of the 8006081G1 VHF
Driver/Power Amplifiers for the AN/GRT-21 modules
(VHF 118-136 MHz) every month.

>From your description, you probably have the UHF
(225-400 MHz) modules for the AN/GRT-22 (NOT GRT-23).
I don't work those, but another tech in our shop does
overhaul those.

The VHF amp has two flat circuit boards and the first
of the two uses one PT-6702 as its output stage to
drive a PT-6708 with a PT-6709 the final stage.

BTW, the companion receivers (VHF and UHF) are the
AN/GRR-23 and AN/GRR-24.

73 - Mac, K2GKK/5
(Since 30 Nov 53)
OKlahoma City, OK



____________________________________
Date: Sat, 1 May 2010 10:12:19 -0400
To: Milsurplus at mailman.qth.net
From: glennmaillist at bellsouth.net
Subject: [Milsurplus] GRT-21/23

I have a module that I got at a hamfest.
It is ITT assy 8004890G1.
It is a Driver/Power Amplifier, RF.
Can anyone verify that this is part of the GRT-21 or GRT-23 transmitter?
These only put out 10 Watts.
This amplifier looks like it is capable of much more with the proper
heatsink.

The output modules (3) are assy number 8004892G1 and each have two RF
power transistors.
The transistors are TRW PT6702.
The transistors have a date code of 7451.
The PA modules look like this

http://www.bpbsurplus.com/lc/cart.php?target=product&product_id=16983&category_id=256

Any help as to what this came from and the device ratings greatly
appreciated.

73
Glenn
WB4UIV