It sounds as if it may be a reactive dummy load for performance testing the
specs of a TX or small amp. But is there any switching of jumper options?
The resistors should be non inductive, maybe Dale or similar brand.
The ones Im familiar with use a big rotary inductor and a vacuum variable
with calibration charts to set a wide range of possibilities. However they
were used for 1 to 5KW units. I have one here that was in use for many years
at National Radio military division. It still comes in handy.
----- Original Message -----
From: "Keith Schreiber" <email@example.com>
Sent: Wednesday, July 18, 2007 6:21 PM
Subject: [Amps] Dummy Load DA-174/GRM-10
> Greetings to the group!
> I'm trying to trace down a schematic or any info on the following item :
> Dummy Load, Electrical DA-174/GRM-10
> I've not been able to find anything about it on the net. This gizmo has a
> Simpson 0-10 RF Ammeter on the front, a squirrel cage blower (with switch
> & pilot light) that cools many 20 watt, wire-wound resistors. These
> resistors are all mounted in a phenolic box, which the blower forces air
> through, and then out the back. The cabinet is filled with all kinds of
> fixed inductors and 850 series doorknob caps. The dimensions are roughly
> 9" wide X 10" high X 15" deep. The input is a female N connector.
> The input connector and the 0-10A RF ammeter are mounted on a 1/4" thick
> phenolic plate (on the front panel.) The cabinet itself is all aluminum,
> with screened vents on the left side and the rear. It's gray in color.
> The front panel also has a fuse for the blower and a black, 5-way binding
> post for a ground connection, in the lower left corner.
> This is the first time the web has let me down in finding info on
> something. The only info I was able to find on this item, was it's NSN
> (National Stock Number) :
>>From that number, I've seen references that it was made by
>>Rockwell-Collins at some division in Richardson, TX. I've got a number
>>called a "CAGE" number too.... if that means anything to anybody. (80058)
> I'd appreciate any info, that anyone could provide. Perhaps you used one
> of these in your military days. I don't even know the frequency range.
> It will not accept power (SWR=19) and an ohmmeter applied to the center
> pin of the N connector, shows "open" to ground. No doubt one of the many
> 20W wire-wound resistors that actually make up the load is open. But the
> way this thing is put together, it's going to be a real chore finding out
> which one. Especially without a schematic.
> Any info on this? I guess it would be best to reply to my regular e-mail
> Thanks & 73 from W8KTH
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