Nice job Tim on that HB  supply.
An interesting item about the PA-109 is that as soon as you applied 12 volts it became active.  The main toggle switch was used to go from Receive only mode(OFF)  to Receive and Transmit (ON). When the Toggle was OFF you were in receive mode and they switched off  the HV supply and transmitter filaments and reduced the input current requirements for 12 volts. The inverter circuit ran at 3 Kc.
Z


On 8/5/2024 2:38 PM, Tim wrote:
Hi Breck - The PA-109 is an interesting piece of obscure history.  I've never seen one in the wild and only 1 photo (yours? online).
Essential gear for GRC-109/RS-1 ops, I had to build my own version so I could run the T/R system at 12 Volts these days.  

It (and my DIY) can also run the GRC-9 receiver directly as they emulate the BA-48 battery - same voltages and connector. I built mine in a spare GRC-109 transmitter case.  A fun project.
https://www.n6cc.com/wp-content/uploads/P9260257.jpg
https://www.n6cc.com/wp-content/uploads/IMG_2744.jpg

Cheers, Tim
N6CC

On Sun, Aug 4, 2024 at 3:11 PM B. Smith via MRCA <[email protected]> wrote:
The Nems Clarke PA-109 has been shipped to another collector.
Z
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