[Collins] Looking for information on the Cunningham C201 and C203tubes

[Dr. Gerald N. Johnson]

On 9/2/2010 8:11 AM, Carl wrote:
> I seriously doubt if Collins used the RCA 203A for long, if at all, as
> it was a 1923 introduced tube of fairly low reliability and obsolete by
> the time Collins got into the BC market. The 203A was simply a higher mu
> 211 and was rated at 100W output in Class C AM service (1934 RCA
> Transmitting Tube Manual) so a pair wouldnt make the 250W of the Collins
> TX.
The 211 went on to be the VT4C of BC191 and BC375 fame (or infamy).

The 1933 Collins Signal articles show tubes like the 203A while the 1935 
Collins Signal articles show common receiving tube numbers, like 245 or 
the common 866 rectifier with mostly C prefixed numbers for the power tubes.
>
> There was almost no order to industrial tube numbering back then and
> companies simply used whatever they wanted. So a RCA 203A was quite
> different from a C203, and CE203 (MV rectifier)
>
> If any Collins documentation exists I feel rather certain that Amperex
> would be at the top of the supplier list as they were very active at the
> time and despised RCA. Personally I believe they made better tubes which
> certainly would have attracted Art Collins.

I don't know what documentation Collins kept in the 30s. I know in the 
60s that every bit of every product had to be covered by a component 
specification. Nothing could reach production without a complete set, 
preferably from a list of preferred parts. Everything had a part number 
down to the least bit of hardware.

These component specifications described the part, who was acceptable to 
make it (like carbon comp resistors excluded IRC), and how to test it. 
Samples had to pass test by the components spec department at intervals 
to stay in use. A significant fraction of the surplus bought by 
McKercher and then by Surplus Sales of Nebraska were parts that had 
survived or failed those component qualifications tests, or incoming 
inspection.

In the 60s, I know Art showed a definite dislike of RCA. Someone 
proposed using RCA 8122 instead of 4CX350 for 300 or so watt linear 
stages and broad band driver stages. Their data sheets show the same 
characteristics, but the 8122 cost half the price of a 4CX350 and fit in 
a 98 cent socket versis the $10 socket for the Eimac tube. This went 
into a working paper which Art dutifully read and responded, saying, 
"I've known Bill Eitel since 1936, we'll use Eimac tubes." Could have 
been he was soured by rotten performance of the RCA 203A. I wasn't all 
that pleased with the Eimac 4CV100,000C that had great plate dissipation 
but the innards of a 4CX35,000 and they were worked to glowing to get 
125KW carrier. We had to melt down many tubes to get Eimac to make tubes 
that would actually meet the data sheet claims. I spent days one time 
with their graphic tube calculator coming up with 123 or 124 KW output 
before figuring in losses. We certainly yanked their chain wanting new 
data or better performing tubes, which VOA may have actually gotten from 
Machlett.
>
> Cunningham receiving tubes would not have used the 201 label as that was
> RCA as in UX-201, and UX-201A which became the ubiqitous 01A of battery
> radio fame. The Cunningham version was imprinted C-301A and also
> CX-301A. Other competitors used varying prefixes and numbering for the
> same tube such as 401A, 501A, etc with a lettered prefix somewhat
> indicating the manufacturer, NU, SY, etc

OK.
>
> Jerry, you still have time to make that trip before the first blizzard.

Only if I don't get finished moved before that first blizzard.
>
> Carl
> KM1H
>
>
73, Jerry, K0CQ, Technical Adviser to the Collins Radio Association.