[ARC5] [Milsurplus] Scott SLRM - Low BFO Injection
Richard Knoppow
1oldlens1 at ix.netcom.com
Wed Sep 11 01:47:21 EDT 2019
I can't find the original post. How is it being determined
that the injection is low? Many receivers have minimal BFO
coupling both to avoid pulling of the BFO by the signal and to
avoid activating the AVC when it can be used on CW.
My AR-88 has fairly low BFO injection but its adequate. The
coupling is via stray capacitance. At some point the wiring was
re-arranged. I tried it both ways and went back to the original.
It works OK for SSB but, as with most receivers without product
detectors, the RF gain has to be run low.
On 9/10/2019 9:44 PM, Bart Lee wrote:
> 2 cents:
>
> The SLR stood for Special Low Radiation. Scott sold the Navy on
> the idea that heterodyne oscillations could betray a ships
> position to a submarine. (That /*maybe*/ happened once in WW I as
> a result of a regenerative receiver ... but better safe than
> sorry, and rich on government contracts). Note the full copper
> shielding on the SLR.
>
> The BFO question is */maybe/* related: another oscillator could
> inject RF and */maybe/* that RF could get out, /*maybe*/... So it
> would make sense to limit the injection. (But I've never seen
> this aspect discussed and don't know of any references).
>
> 73 de Bart, K6VK ##
> -- --
> Bart LeeK6VK, CHRS Archivist, AWA, ARRL
>
> Texts only to: 415 902 7168
>
> www.bartlee.com <http://www.bartlee.com/>
>
> {KV6LEE(at)gmail(dot)com} ##
>
> <http://www.LawForHams.com>
>
>
>
> On Mon, Sep 9, 2019 at 8:14 AM Hubert Miller <Kargo_cult at msn.com
> <mailto:Kargo_cult at msn.com>> wrote:
>
>
>
> -----Original Message-----
> From: milsurplus-bounces at mailman.qth.net
> <mailto:milsurplus-bounces at mailman.qth.net>
> <milsurplus-bounces at mailman.qth.net
> <mailto:milsurplus-bounces at mailman.qth.net>> On Behalf Of
> Kenneth G. Gordon
> Sent: Sunday, September 8, 2019 7:44 PM
> To: milsurplus at mailman.qth.net
> <mailto:milsurplus at mailman.qth.net>; David Stinson
> <arc5 at ix.netcom.com <mailto:arc5 at ix.netcom.com>>;
> aRC5 at mailman.qth.net <mailto:aRC5 at mailman.qth.net>
> Subject: Re: [Milsurplus] Scott SLRM - Low BFO Injection
>
> I have always thought the Scott receivers were excellent.
>
> One of the first such I ever had was an SLR-F....which was
> named the RCH by the Navy.
>
> The SLR-F/RCH covers some MF and lower HF frequencies, up to
> 24 MHz.
>
> I have two now, one of which is deaf, which I want to restore
> and use.
>
> They are excellent receivers, stable, reliable, not
> particularly sensitive, but sensitive enough.
>
> And I really like the flywheel tuning.
>
> The dial on your SLR-M looks almost identical to that in the
> SLR-F.
>
> BTW, if you don't know, the SLR stand for Super Low Radiation.
>
> Ken W7EKB
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--
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL
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