[R-390] Single Sideband reception with the R-390/R-390A

[Dan Merz]

Hi,  I was pretty happy with the Lankford mod using a couple of diodes on my
390a but this didn't handle range of signal strengths without riding the rf
gain control.  I built an outboard product detector ala Ed Newman
WB2LHI/Alex AI2Q that uses a LM1496.  I've been happy with this and I never
have to touch the rf gain control,  which remains at the highest gain
position.  The unit has built-in agc and is attached with no mods to the
set,  with 4 connections (i.f., diode load, audio, agc) at the back of the
390a or 390.  My version was built using some old National NC 100 coils for
the bfo and tuned output circuit for the bfo.  It is  set to the appropriate
sideband with a knob on the front of the coil can and exhibits no drift of
the setting.  I can easily switch the unit out and compare original
performance without it.  The biggest advantage is the improved agc,  with
some slight improvement in signal quality,  compared to the original
detection scheme in the 390.  I use it all the time on my 390.  I was
dedicated to the idea of an outboard unit without modifying the innards of
the radio. Mine uses the original audio circuit of the 390,  though one
could feed the output of the PD to an external amp.  A small audio preamp is
included in the circuit to adjust the level going back into the 390.  I have
no experience with other auxilary ssb detectors so can't offer anything on
relative performance.  I prefer listening to the 390 compared to my
unmodified NRD-525 because the audio is better.  Best regards,  Dan.      

-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
On Behalf Of Brad Huff
Sent: Thursday, January 19, 2006 1:55 AM
To: r-390 at mailman.qth.net
Subject: [R-390] Single Sideband reception with the R-390/R-390A

Gentlemen,
I would like to thank all of the people that responded to my signal
generator question a few days ago. I received responses within minutes of my
posting. Unbelievable! That is what makes this group so great. I would now
like to open a discussion about single side band reception with the
R-390/R-390A series receivers. For the purpose of this discussion let us
assume that the radio has been altered such that the AGC has been modified
for proper SSB reception.  I have had experience with:
1) the radio with no external adaptors and increased BFO injection.
2) a CV-591A SSB adaptor.
3) a Hammarlund HC-10.
4) a Central Electronics Sideband Slicer.
5) a Sherwood Engineering SE-3
6) a PD-1.
I have not had any experience with the Capt. Lee onboard product detector
mod or a couple of the home brew units that are out there. I have schematics
and have ordered parts for one of the home brew units I just have not had
the time to build it yet so I can not comment on these. The adaptors that I
have mentioned are not necessarily in any particular order as far as
favorites, I just listed them as I thought of them.
They all work. Some work better than others, and some folks can probably
detect differences in the various units better than my tin ear. That is
where you guys come in. I am curious as to your experiences and what you
feel are the best units. Maybe we could rank the units that I have
mentioned. Some units require external hardware to operate, that is,
external amplifiers etc.. Some units will allow the audio to be fed back in
to the receiver at the rear of the unit. Much has been written about the
quality of the stock audio but I have found that the audio is quite
acceptable if the audio deck is altered using Mike Murphy's suggestions. Any
thoughts? Please respond to the entire group, it will be interesting to see
what everyone's experiences are.-Brad
_____________________________________________________________
R-390 mailing list
Home: http://mailman.qth.net/mailman/listinfo/r-390
Help: http://mailman.qth.net/faq.htm
Post: mailto:R-390 at mailman.qth.net
Unsubscribe: http://mailman.qth.net/mailman/options/r-390