[Milsurplus] Heterodyne Frequency Meters

[Jim Whartenby]

Would the Navy use an SCR-221? <grin>
I am under the impression that wide receiver IF's were used because of netting issues.  So many transmitters were almost "on" frequency.  Possibly due to the effects of temperature and humidity changes during flight.  So the conditions on the aircraft carrier flight deck were not what would be seen at altitude.  The reason for the photo of the frequency meter on the flight line is anyone's guess.  Last minute change of frequency?  Last minute change of aircraft for the mission?
The late war AN/ARR-15 receiver is remarkably stable and had frequency memory but still had a wide IF since it was used with WW2 era radios which didn't have that kind of stability.  I believe once SSB became the norm, frequency synthesizers were common, the IF bandwidth was narrowed and the radio operator crewman position was eliminated.
I don't know enough about the various aircraft used by the Navy during WW2 to know if the Navy followed the Army in fix tuning receivers.  Did the ARB always use the Coffee Grinder or was it often fixed tuned?  I would assume that aircraft big enough to need a radioman (TBM) would have no issues with netting but a single seater fighter would be a different story.
Jim

Too much agreement kills a chat.  E. Cleaver

-----Original Message-----
From: Hubert Miller <Kargo_cult at msn.com>
To: milsurplus at mailman.qth.net <milsurplus at mailman.qth.net>
Sent: Thu, Apr 22, 2021 3:06 pm
Subject: Re: [Milsurplus] Heterodyne Frequency Meters

#yiv4837526745 #yiv4837526745 -- _filtered {} _filtered {}#yiv4837526745 #yiv4837526745 p.yiv4837526745MsoNormal, #yiv4837526745 li.yiv4837526745MsoNormal, #yiv4837526745 div.yiv4837526745MsoNormal {margin:0in;font-size:11.0pt;font-family:sans-serif;}#yiv4837526745 span.yiv4837526745EmailStyle19 {font-family:sans-serif;color:windowtext;font-weight:normal;font-style:normal;}#yiv4837526745 .yiv4837526745MsoChpDefault {font-size:10.0pt;} _filtered {}#yiv4837526745 div.yiv4837526745WordSection1 {}#yiv4837526745 Probably we have all seen that photo of some ground crew person holding an LM or BC-221 next to a single prop single place plane on the flight line. I suppose that was for a last minute tune up of the Command equipment? Or maybe a staged photo, as the pilot probably couldn't reach the Command equipment in this plane anyway?-Hue Miller   ______________________________________________________________
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