[Premium-Rx] New to the list and Racal 3702

[Michael O'Beirne]

Dear Claudio

I really would not bother to make comparisons for the RA3702.  I have the 
single receiver version, the 3701, and it is absolutely wonderful; head and 
shoulders over the opposition except possibly for the old RA1772.  The 
recovered audio sounds very smooth, natural and agreeable and the AGC is 
nice and docile.

The lovely silky smooth spin tune will put every thing else in the shade. If 
you loosen the shaft brake and give the knob a good flick, it will rotate 
for at least 12 seconds.

The Half-Octave filter module is very rare.  In view of the 3702's very high 
IP2 and IP3 the module is rarely ever needed.  Perhaps get one if you have a 
10kW transmitter down the road!  Most of us are not so plagued.

Your twin receiver version is particularly good because it can be set up to 
give proper diversity reception.  Each receiver needs a antenna well apart 
from the other to minimise the effect of fading (spaced diversity). 
Alternatively, connect a vertical antenna to one receiver and a horizontal 
antenna to the other (polarisation diversity).

Racal for example made a small active antenna using 2 dipoles mounted at 
right angles specifically designed for polarisation diversity.  This was 
much used for a Racal military data HF transceiver known as "Kaynard". 
These were often used as reserve comms at embassies if all else failed, and 
also by Special Forces.

These are well established professional techniques for data reception where 
selective fading will severely affect the timing of the data, and will lead 
to printing corruption unless decent error detection and correction features 
are built into the data protocol, or, as in the case of Kaynard, it uses a 
version of the very efficient Piccolo data modulation or similar.

73s
Michael G8MOB

----- Original Message ----- 
From: "moreradio" <moreradio at alice.it>
To: <premium-rx at mailman.qth.net>
Sent: Sunday, February 12, 2012 11:12 AM
Subject: [Premium-Rx] New to the list and Racal 3702


> Hi to all,
> I'm the proud owner of a magnificient 3702 recently acquired.
> I wonder if someone has spare modules to swap or sell.
>
> I'm interested in particular to this two:
>
> -Sub-octave filter module (as preselector)
> -IF filter module (can accommodate 7 filters)
>
> The receiver works wery well. I'm using it mainly for short wave listening
> (tropical bands dxing) and as a reference receiver to make comparision 
> among
> various radio equipments I own.
>
> All the best
>
> Claudio IZ0HTS in Rome.
>
>
>
>
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