[Milsurplus] Comparison of Navy vs Army Air Corps equipment

[Kenneth G. Gordon]

On 2 Jul 2006 at 17:46, windy10605 at juno.com wrote:

> I would assume there are many people out there with the expertise to
> supply a specification comparison between these two medium power CW/AM
> rigs for hams ..... I have always looked at them as having similar
> capabilities (dual 1625s modulated by 1625s, etc, etc).
> 
> Navy TCS setup and Army Air Corps BC-348 with ARC-5 Tx's and MD-7
> Modulator. I believe these were both very typical ham installations in
> the 50s (got my license in 1960).
> 
> The popularity of the ARC-5 stuff is always high, the TCS seems to
> vary ...sometimes it's high sometimes it goes away ...really don't
> know why ....other than they "look dull". But this question is about
> performance and capability, not aesthetics . Believe they were quite
> popular in the late 40s and 50s.

The biggest problem with the TCS is the selectivity of the receiver. It is 
VERY broad, and is difficult to fix without a major rebuild.

The ARC-5 receivers up through 80 meters were more selective. The 
40 meter ARC-5 receiver was definitely NOT.

Also, at the time, the ARC-5 receivers were much less expensive than 
the TCS, so they were used by beginners much more often than the 
TCS.

However, one thing that mitigated against the use of the ARC-5 in a 
better ham station was the fact that they were single-band only.

The BC-348 was used by many hams, but not usually with the ARC-5 
transmitter...at least I can't remember any. I used a BC-348 for a while 
and really liked it. However, one of my Elmers had connected a BC 
band ARC-5 receiver as a "Q 5er" and that made a big difference in 
selectivity. I never used the BC-348 "barefoot", although many hams in 
my hometown did. My transmitter at the time was a DX-35.

When I was young, many older hams used the TCS setup, despite its 
broad selectivity. It was quite suitable for 160, 80, and 40 meter AM 
work, and was used extensively by both CAP and MARS.

As far as the transmitters are concerned, both were difficult for the 
average ham to use PROPERLY, since both were designed to drive a 
short antenna. However the TCS had an optional loading coil setup that 
many hams used, and many hams also used an antenna coupler 
between the rig and the antenna. 

The ARC-5 transmitters were almost never used properly by hams, 
since most didn't understand that they were designed to drive a 5 ohm 
(or lower!) antenna impedance.

SOME hams did use them correctly, by connecting a large variable 
capacitor between the antenna post and antenna, but they were in the 
minority.

The TCS transmitter's advantage was that it was (if I remember 
correctly) completely self contained except for power supply: i.e., the 
modulator wasn't separate, like in the ARC-5.

In any case, I remember many hams in my hometown of Missoula, 
Montana using the TCS, including a couple of my Elmers, but not so 
many using the complete ARC-5 setup. In fact, I don't remember even 
one.

Novices were the ones who used the ARC-5 receivers and transmitters, 
since they were cheap, and they didn't have voice privileges, so didn't 
need a modulator.

This was in the 1956 time-frame by the way.

Even our Sheriff's Office had a BC-191 and BC-348 setup for 
emergency use. I used it as the base station for a search for a lost 
hunter in the Bob Marshall Wilderness area, while an AN/GRC-9 with 
PE-162 generator was used at the other end, about 50 miles away.

Ken Gordon W7EKB