[Milsurplus] U.S. Army TRF LF receiver 1934

[Mike Feher]

I believe Clete meant superhet receivers were avoided especially for ships
at sea due to LO re-radiation. The TRFs were preferred. - 73 - Mike 

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 


-----Original Message-----
From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of
Kenneth G. Gordon
Sent: Tuesday, November 10, 2015 11:01 AM
To: C.Whitaker
Cc: Milsurplus
Subject: Re: [Milsurplus] U.S. Army TRF LF receiver 1934

On 10 Nov 2015 at 9:28, C.Whitaker wrote:

> de WB2CPN
> TRF receivers did not have a local oscillator, and were avoided where 
> the LO could be picked up.  Such as Navy at sea.
> WWII trivia, but factual.
> 73  Clete

Not completely true: the RAK/RAL were TRF and used extensively by the Navy
all during WWII. The RBL was a TRF also, and I am sure there were others.
One of my RALs had been the main HF receiver for the USS Pintado a fleet
sub.

The Navy specified a very low radiation level at the antenna, something like
a few micro-micro-watts of radiation at the antenna connection, and the TRFs
that the Navy used all met that specification.

National had to add a second RF amp stage to one of their superhets before
the Navy would accept it for use on ships.

In fact, from my reading, many of the old Navy radio ops preferred the
RAK/RAL over the newer RBB/RBC since they insisted that the earlier
receivers were less susceptible to overload by nearby transmitters due to
their more extensive shielding.

Ken W7EKB
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