[Milsurplus] RBB receiver - SRR-11/12/13

[Kenneth G. Gordon]

On 27 Jan 2016 at 13:57, w8au at sssnet.com wrote:

> The RBA/B/C series remained in the fleet through the 1960's and even later
> for auxiliary type ships.  This was, in part, because of the high-maintenance
> required for the "replacement" SRR-11/12/13 types. (modular pencil tube
> versions)

One of the biggest problems with the SRR-11/12/13 series was that the 
designers set all the pentodes and tetrodes so that the screen voltages were 
identical to the plate voltages.

The receivers ran incredibly hot with this setup.

Back in the 1970s, I worked with a researcher who used a bunch of the 
SRR-11s running 24/7.

I added a properly bypassed 56 K resistor in the screen voltage feed of each 
pentode and tetrode, which dropped the heat produced a lot, and they ran 
without problems from then on.  The reduced screen voltage did not seem to 
impair the receivers in any way.

I got so I liked them...except for those damned pot-metal cranks on the 
band-switch mechanism which were always breaking.

As long as one kept the receiver on one band, they didn't matter.

Someone on Josh Rovero's page designed a cheap and effective fix for 
those things, though.

BTW, the filament voltage regulator that RCA came up with to replace the 
ballast tube was sheer genius: a pair of back-to-back zeners and two 
resistors. Snazzy! :-)

http://www.w7ekb.com/glowbugs/Military/SRR_Radios/Ballast%20Tube%20
Replacement_files/Ballast%20Tube%20Replacement.htm

Ken W7EKB