[Milsurplus] Comparison of Navy vs Army Air Corps equipment

[Scott Johnson]

It is important to note that on AM, the TCS is using only one 1625 for a 
final, and the modulator is not capable of 100% modulating the final due 
to lack of audio drive. (Many hams remedied these problems)

Scott

Kenneth G. Gordon wrote:
> 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
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