[ARC5] trf

[Geoff]

While a TRF may require 3 RF amps a TRF-regen does not unless there is a lot 
of circuit loss. The added front end selectivty of either 1930's design is 
minimal.

The RAK/RAL use tubes designed in 1933 which are actually 6,3V versions of 
the ones designed in 1931.

Even so the CW sensivity of the RAL is easily .5uV thru 14MHz for a 10dB SNR 
(NOT MDS) when the input is well matched to the signal generator.

With an adaptor and a 6SG7 in place of the first 6D6 it would likely do well 
on 15M or even go with a 7 pin miniature such as the 6BZ6 or 6GM6, The RAL 
covers up to 23MHz.

The RAK/RAL also have an excellent audio limiter which works excellent for 
storm static as well as a sort of audio AVC. The selectable audio filters 
also do a good job on CW QRM.
OTOH the tuning and lack of calibration is far from user friendly so its not 
a band scanner.

Both are around 70# plus another 40# for the remote PS but a HB one is very 
simple as long as its well filtered. I use an original on the RAK and a SS 
all regulated DC version on the RAL where it is usually used on 30M.






----- Original Message ----- 
From: "Alan Morriss" <mohawk at clara.co.uk>
To: <arc5 at mailman.qth.net>
Sent: Friday, July 06, 2012 12:52 PM
Subject: [ARC5] trf


> hi ken , look up the Lo6 on the web. in my opinion it is greatly superior 
> to the RAK. there are 3 RF stages , 6 tuned circuits and it is sensitive 
> to 0.4 microvolts on cw. of course you have to have a fair bit of muscle 
> to shift it !   perhaps the finest rx ever is the telefunken E52 . this is 
> a superhet , and my 1943 one is better than my harris RF3200 in my 
> opinion. in the meantime , i am getting on with making up the connectors 
> for my ARC5 set up. alan G4GEN
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