[NJARC] Early aircraft radio

[Al Klase]

That should have said "...difficulties associated with installing an 
efficient LF transmitting antenna in a small plane....."

On 8/18/2013 10:42 PM, Al Klase wrote:
> Just remember
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>
> _________________________________________________________
> 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
>> Reply = Poster
>> Reply All = Everyone
>>
>> _________________________________________________________
>> 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/