[NJARC] Early aircraft radio

[Al Klase]

Hi Pete,

I'm not an aviation guy, but I'll make a few comments.

Back in the day, say pre-WWII, general aviation (read private) aircraft 
often carried low-powered AM transmitters in the 2-3 MHz range to 
communicate to control towers.  The towers broadcast on a long-wave 
frequency, I think the standard was something like 278 KHz, and listened 
on the HF frequency.  This was because of the difficulties associated 
with installing an efficient HF transmitting antenna in a small plane.  
VHF comms in the present 120 MHz range were introduced to civilian use 
sometime after the war.  The must have been considerable overlap.  (I'm 
told planes without transmitters listened to the tower and wagged their 
wings in response.)

I'm speculating that there was a period of time where you could talk to 
the tower on VHF, and hear their response on long-wave.

I have a small crystal controlled VHF AM stand-alone transmitter built 
by RCA.  It's in a cylinderical case designed to be mounted in a 
standard aircraft control panel cutout about 4 inches in diameter.  I've 
always wondered what was going on.

Perhaps we have an old-time pilot that can clear this up.

Does you radio have a connection for a receiving loop?  DF'ing broadcast 
stations was/is standard practice.

Al

On 8/18/2013 11:01 AM, Pete Malvasi wrote:
> Just remember
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> _________________________________________________________
> I recently bought a bendix airplane transmitter ca 1950 and noticed its both a transmitter and receiver. It transmits on the 120mhz am band but receives both BC band and 200-500khz.
>
> Does anyone know about this - the dual band t and r aspect of aircraft radio then? This is new to me.
>
> 73 Pete W2PM
>
> Sent from my iPhone
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-- 
Al Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/