[Milsurplus] BC-375 Heavy?

[Mike Morrow]

Bob wrote:

>Am I the only one who finds it hard to believe that the BC-375 ever was  
>considered a lightweight aircraft radio?... It just seems like you could
>have gotten the job done without quite as much weight.

I've always thought that, ignoring all those tuning units, the BC-375 was reasonably compact and lightweight for its era.  A BC-375 with tuning unit and shock mounts still weighs less than 70 lbm.  That's also very close to the weight of later military HF RT units like the RT-380/AR, RT-91/ARC-2, RT-311/ARC-38, 618S-1, etc.

The (obviously much more capable) AN/ART-13 is considerably heavier (again, ignoring tuning units) and a lot more expensize.

The USN's GP-7 (in my opinion, a far poorer overall design than the BC-375) is no cream puff either, at about 55 lbm for transmitter with tuning unit.  At least no dynomotor was needed.  I don't know how much the USN's GO-9 monster weighed, but a BC-375 is much lighter.

In the early 1950s, the USAF replaced AN/ARC-8s (BC-348 + ART-13) with the R-128/ARC-21.  This was an AM/CW RT in a 18 inch diameter pressurized drum.  The RT unit alone weighs 132 lbm!!!  Then you had the dynamotors (three) or other power supplies, antenna matching units, control boxes, etc. for a total system weight approching 300 lbm.  Ditto for the USB modification of the ARC-21, the RT-400/ARC-65.  I had an opportunity to buy dirt cheap an RT-400/ARC-65 in excellent condition a few years ago.   I passed it up because I've trained myself to avoid gear that weighs more than I can easily hoist.

But I'd agree that, looking at the list of gear above, this "lightweight" aircraft gear sure packs the pounds!

I wish that the design and tube lineup for the BC-375 had been modernized before war's end, similar to what was done for the BC-348 with the J, N, Q models.  It would have been great, for example, to have seen the VT-4-Cs replaced with a 1625 and a 811 MOPA, and two 811s for modulation.  Get rid of that VT-25-C tube in the speech amp too.

73,
Mike / KK5F