The WW2 and Korean era VHF rigs, and the GRC-27,PRC-41,ARC-27,R-361,and GRA-53/VRC-24 we used in the Air Force in the early 70s were rated at 3 microvolts. The BC-639 could sometimes do a little better, but getting a GRC-27 to do it took hours of tweaking and hair pulling. All of them would break squelch perfectly at 3.5 microvolts day in and day out. I think pre-war VHF was mostly close to airports, so the 10 microvolts would have likely have been fine.

   B. Gentry, KA2IVY

  

On 7/20/25 2:11 PM, Jim Whartenby via Milsurplus wrote:
10uV input for 50mW audio output doesn't seem all that bad for a receiver with no RF amplification.  Was this a civilian aviation VHF transceiver drafted into the military early in WW2?  I seem to remember that the ARC-4 was in service before either the ARC-1 or ARC-3, but you know how memory can confuse things!
Jim

Logic: Method used to arrive at the wrong conclusion, with confidence.  Murphy


On Sunday, July 20, 2025 at 06:16:59 AM CDT, Rob Flory <[email protected]> wrote:


Hi,

I am an ARC-4/WE 233 person in recovery.

I pursued it because they were installed on USS Massachusetts, and because they work on the 2m Amateur band.

I used to take mine around to shows and talk between it and my ARC-1.

Read the description of the exercise K4CHE and I did, which revealed the relative  deafness of the ARC-4.  


RF
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