[R-390] Best approach for SSB mod on R-390A

[Cecil Acuff]

The SE-3 is a complete IF/Sync Detector/Product Detector/Audio system, with 
an incorporated AGC system I'm quite sure.  Should be no need to fiddle with 
the RF Gain.  I've heard one of these things work and it's simply amazing. 
Brings any of the old Boatanchor radios up to date as far as detection of 
Sync AM and SSB.  Good part is he offers a switching system that allows a 
whole rack of radio's to be routed through it with adjustments for the 
varying IF output levels found between radios such as the SP-600 and R-390 
series. The PD2 is a new product and Jan would have to speak to the 
effectiveness of the need to fiddle with the RF gain.

My understanding of the issue with the RF gain on the stock boatanchor is 
more to do with the level of BFO injection.  It's way too low for SSB work 
and the RF signal level has to be kept below the injection level of the BFO 
to keep things working properly.  If you are not using the BFO for SSB 
detection the RF gain level should become a non-issue.

I would love to hear from anyone that might own some of these outboard 
devices...I know there were several of the earlier PD-1's out there and a 
few SE-3's as well....

Cecil...
----- Original Message ----- 
From: "Dan Merz" <mdmerz at verizon.net>
To: "'Cecil Acuff'" <chacuff at cableone.net>; "'Tom Frobase'" 
<tfrobase at gmail.com>; <R-390 at mailman.qth.net>
Sent: Tuesday, December 22, 2009 4:28 PM
Subject: RE: [R-390] Best approach for SSB mod on R-390A


> Hi,  I would ask myself which of these detectors has any gain control 
> built
> into it so you're not fussing with the rf control manually on strong
> signals.  As far as I was concerned,  this was the main reason for going
> beyond the 2-diode approach.  I'm pretty sure the Skirrow kit doesn't , 
> and
> looking at the SE-3 and PD-2  I see no specification that addresses this
> issue so I assume they don't either.  Maybe someone with experience with
> these latter two detectors could clarify that point.  But if  fussing with
> the rf gain manually doesn't bother you,  then take your pick for all the
> other features offered,  or just stick with the 2-diode fix.  The outboard
> detector that Ed mentioned and the one that I built provide a line back to
> the agc for gain control based on level at the detector and use a product
> detector.   Dan.
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
> On Behalf Of Cecil Acuff
> Sent: Tuesday, December 22, 2009 7:01 AM
> To: Tom Frobase; R-390 at mailman.qth.net
> Subject: Re: [R-390] Best approach for SSB mod on R-390A
>
> Top of the heap....Sherwood SE-3.  Treat yourself...
>
> www.sherweng.com
>
> Next in line....PD-2
>
> http://electronicspecialtyproducts.com/
>
> Also there was a VE making a kit...Jan Skirrow, think he was a member here
> for quite some time.  External Syncro/product detector.  Worked real well 
> as
> I understand.
>
> http://skirrow.org/Boatanchors/TechTalk10.pdf
>
> Then there are the various mods you've read about that utilize the BFO to 
> do
> SSB that are slight improvements on just using the radio as is.
>
> You will no doubt get many emails telling you it works fine just like it
> is...and in a fashion it does...it you desensitize the radio by backing 
> down
> on the RF gain and what not...
>
> It works but really...the radio was never designed to do SSB.
>
> There are also a few product detector mods which are probably worth 
> looking
> into further.  Problem is they are radio specific.  You mod that radio and
> that radio alone works...but if you have several radio's the external
> approach is a better choice.  (SE-3 or PD-2)
>
> Just my opinion though...
>
> Merry Christmas and Happy New Years to the group!
>
> Cecil Acuff
> K5DL
> ----- Original Message -----
> From: "Tom Frobase" <tfrobase at gmail.com>
> To: <R-390 at mailman.qth.net>
> Sent: Monday, December 21, 2009 7:20 PM
> Subject: [R-390] Best approach for SSB mod on R-390A
>
>
>> What is the suggested approach for SSB modification for the R-390A.
>>
>> Is the 2 diode modification worth attempting?   I know it has been
>> covered here more than once just wanted to solicit the current thinking
>> on the matter ... thank you ... tom, N3LLL
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