I am looking for parts to build a portable tube transmitter-receiver
project from an artcle that appeared in the September 1950's QST.
It utilises a dual potentiometer, one gang is 2M ohm, the other is 5K ohms.
The parts list gives the 2M as "RC M13-139" and the 5K as "IRC PQ 11-114".
Do these numbers mean anything to anyone, and if so, please can you explain?
Any assistance will be greatly appreciated.

In article ,
Mahoidar wrote:
I am looking for parts to build a portable tube transmitter-receiver
project from an artcle that appeared in the September 1950's QST.
It utilises a dual potentiometer, one gang is 2M ohm, the other is 5K ohms.
The parts list gives the 2M as "RC M13-139" and the 5K as "IRC PQ 11-114".
Do these numbers mean anything to anyone, and if so, please can you explain?
Any assistance will be greatly appreciated.

In that time frame, you could buy the front and rear portions of a dual
pot seperately and snap them together. There were versions where one
shaft turned both and other versions where the front pot had a hollow
shaft and the rear shaft fitted inside it, and they could be turned
independantly. If the second case is what you need, just use 2 seperate
pots. For the first case, you are probably SOL.

--
Rich Greenberg Sarasota, FL, USA richgr atsign panix.com + 1 941 378 2097
Eastern time. N6LRT I speak for myself & my dogs only. VM'er since CP-67
Canines: Val, Red, Shasta, Zero & Casey (At the bridge) Owner:Chinook-L
Canines: Red & Cinnar (Siberians) Retired at the beach Asst Owner:Sibernet-L

Mahoidar wrote:
I am looking for parts to build a portable tube transmitter-receiver
project from an artcle that appeared in the September 1950's QST.
It utilises a dual potentiometer, one gang is 2M ohm, the other is 5K ohms.
The parts list gives the 2M as "RC M13-139" and the 5K as "IRC PQ 11-114".
Do these numbers mean anything to anyone, and if so, please can you explain?
Any assistance will be greatly appreciated.

I think those are numbers from IRC, a company which still exists as part
of the Vishay empire, I think. They are probably not useful.

I think you may be able to get stacking pots still from CTS. And the
Mod-Pot system is still available but relatively low power.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On Sat, 18 Dec 2010, Mahoidar wrote:

I am looking for parts to build a portable tube transmitter-receiver
project from an artcle that appeared in the September 1950's QST.
It utilises a dual potentiometer, one gang is 2M ohm, the other is 5K ohms.
The parts list gives the 2M as "RC M13-139" and the 5K as "IRC PQ 11-114".
Do these numbers mean anything to anyone, and if so, please can you explain?
Any assistance will be greatly appreciated.

But what are the pots doing? Is this a space saving thing, or is there
some concrete reason why the pots are ganged? Even if they "need" to be
ganged, the circuit will define why, and we don't know what the circuit
is.

Michael VE2BVW

On 12/18/2010 4:42 PM, Mahoidar wrote:
I am looking for parts to build a portable tube transmitter-receiver
project from an artcle that appeared in the September 1950's QST.
It utilises a dual potentiometer, one gang is 2M ohm, the other is 5K ohms.
The parts list gives the 2M as "RC M13-139" and the 5K as "IRC PQ 11-114".
Do these numbers mean anything to anyone, and if so, please can you explain?
Any assistance will be greatly appreciated.



Hi,

You can use two pots - one is for the rcvr audio gain,
and the other is for IF gain, as explained on page 19 of the article.
Use an audio taper pot for the 2M pot section,
and a linear pot for the 5K.

"Michael Black" wrote in message
ple.net...
On Sat, 18 Dec 2010, Mahoidar wrote:

I am looking for parts to build a portable tube transmitter-receiver
project from an artcle that appeared in the September 1950's QST.
It utilises a dual potentiometer, one gang is 2M ohm, the other is 5K
ohms.
The parts list gives the 2M as "RC M13-139" and the 5K as "IRC PQ
11-114".
Do these numbers mean anything to anyone, and if so, please can you
explain?
Any assistance will be greatly appreciated.

But what are the pots doing? Is this a space saving thing, or is there
some concrete reason why the pots are ganged? Even if they "need" to be
ganged, the circuit will define why, and we don't know what the circuit
is.

Michael VE2BVW


The pots are ganged because one controls the audio gain and the other
controls bias on the grid of the convertor tube. The circuit in question is
"The Mountaineer" - A Hiker's Portable,
featured in QST for September 1950.
I suppose two seperate pots could be used, but a dual pot makes life easier.

This guy can make any pot you could ever need.
http://www.oldradioparts.net/

Darrell, WA5VGO