[Milsurplus] ARC-4

[B. Smith]

10 uV is more than adequate for Air to Air and Air to Ground service. 
Actually it is overkill.   When I was contracted to install an FAA 
Ground Service Facility  for aircraft to accept clearances while on the 
ground - the FAA ground equipment receivers were set to "Break Squelch 
at 50uV. Being an aviator and having flown with some of the older 
equipment nothing was more irritating than have a receiver squelch set 
to a 5 or 10 uV sensitivity and having the squelch break without hearing 
a signal. So the Nav or Radio op would adjust the sets in flight. All 
VHF receivers were prone to Precip Static and we liked to have the 
receiver squelch set fairly tight.
K4CHE

On 7/20/2025 3:11 PM, kgordon2006 wrote:
> My understanding of the ARC-4 is that it was originally a Western 
> Electric-designed commercial rig before WWII and was then picked up 
> and used by the military before any subsequent better rigs were 
> designed and put in service.
>
> And I agree with you: 10 uV sensitivity isn't all that bad for a rig 
> with no RF amp.
>
> Although I have never yet had an opportunity to use one, I suspect it 
> has unnecessarily bad "publicity" associated with it by some 
> inexperienced hams.
>
> I would respect K4CHE's ideas on this matter, and would like to hear 
> what he has to say about it.
>
> Ken W7EKB
>
>
>
> Sent via the Samsung Galaxy S21 5G, an AT&T 5G smartphone
>
>
> -------- Original message --------
> From: Jim Whartenby via Milsurplus <milsurplus at mailman.qth.net>
> Date: 7/20/25 11:12 (GMT-08:00)
> To: milsurplus <milsurplus at mailman.qth.net>
> Subject: Re: [Milsurplus] ARC-4
>
> 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 
> <farmer.rob.flory at gmail.com> 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.
>
> https://youtu.be/MYWgLHcVH0k?si=xjydC_IPf5AK9FmA
>
> RF
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