[Premium-Rx] Racal RA 3701

[Clemens Ostergaard]

Returning from Copenhagen, I would like to thank Chuck, Andrew, Danny,
Michael and Pat for replies to my queries. Rich in content, and in
helpfulness, they once again show what a great list this is. I've noted the
many good points made, and will draw on them as I go along.

I used the RA 17 and the (great) 1772 before this one. They were/are special
rx's, and its obvious that Fred Osterman did not let the 3701 grace the back
of his book just because of its suave good looks, hi.

Best,

Clemens

On Sat, Sep 10, 2011 at 6:10 PM, Danny Higgins <danny.higgins at keme.co.uk>wrote:

> Hi Pat.
>
> I agree about the Schaffner IEC inlets.  I've had 2 go on me, and the smell
> is not very nice.  It seems that it is the EMC filter section that fails
> and
> produces some smoke and brown oily goo.  Fortunately I was in the shack
> both
> times and was able to switch things off quickly, although they filters were
> still smoking.  I don't know what would have happened if they had been
> unattended when they failed.  I had heard other reports of these filters
> disintegrating in Racal equipments (one of mine was an RA3702 and the other
> was the MA3752 Drive Unit which uses the same chassis).  I spoke to
> Schaffner who denied all knowledge of batch problems.  I replaced one with
> the same Schaffner part at a cost of about £28, but when the second one
> went
> I took a hacksaw and removed the EMC filter section and replaced it with
> another (non-Schaffner) and put it back together with some Araldite.  I'll
> do this to the rest of my units before I start using them in earnest.
>
> Danny, G3XVR
>
> -----Original Message-----
> From: premium-rx-bounces at mailman.qth.net
> [mailto:premium-rx-bounces at mailman.qth.net] On Behalf Of Pat1McA at aol.com
> Sent: 10 September 2011 16:30
> To: clemenso at gmail.com
> Cc: premium-rx at mailman.qth.net
> Subject: Re: [Premium-Rx] Racal RA 3701
>
>  Hello Clemens.
>
> RA3701. Serial Numbers. Do not take much notice of the S/Ns. A lot  more
> remote control receivers with a blank front panel were made so the  fewer
> Manual Operator Front panels will have lower S/Ns.
>
> To my knowledge very few Preselectors were ever produced, they were a very
> expensive option.
>
> The RA3701 displays are totally different to the ones used in the RA1792.
> As I recall and it is a few years ago, only the Right Hand Side Mode
> display
>
> was  adjustable for viewing angle the others were adjustable for brightness
>  only.
>
> I may be mistaken and getting mixed up with the RA3791!  Memory is
> failing.....now where was I ?......
>
> The RA3701 is very well made. The BITE is quite amazing.
>
> The let down is the "made to a price" IF Filters in the Filter Unit. These
> have rather poor ultimate skirt attenuation.
>
> If you can ever get hold of the Optional IF Filter Unit it takes the
> "Standard size" larger STC/ITT Filters and gives better selectivity and
> easier
> to find Filters.
>
> The main RA3701 fault is the Schaffner IEC Mains Filter. These regularly go
>  short circuit. Whether this is because the normal supply voltage here is
> 240v  a.c. or whether a lot of the RA3701s used a faulty batch is
> debateable.
>
> The RA3791 is a lower quality "made to a beancounter's price" receiver
> than the RA3790 but it is a much better performer.
>
> It is the ONLY DSP receiver that I have been able to test to specification
> using exactly the same techniques as those used for an analogue receiver
> like the RA3701.
>
> 73 de Pat G3YFK
>
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