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

[Cecil Acuff]

Somehow I didn't get Don's post...

Don I would say yours is broken...that is not at all the experience I have 
seen nor heard from a local that used one for a very long time.

Sherwood is also very particular about his designs and would probably invite 
it to be sent to him for evaluation.

Cecil...
----- Original Message ----- 
From: "David Wise" <David_Wise at Phoenix.com>
To: <r-390 at mailman.qth.net>
Sent: Friday, December 25, 2009 12:00 PM
Subject: Re: [R-390] Best approach for SSB mod on R-390A


> My SE-3's oscillator is very steady.
> I wonder if there are good ones and bad ones.
>
> Also, without manual controls, the detector has to
> guess the operator's intentions, based on, say,
> tuning rate.  I don't like machines trying to
> read my mind, because they usually get it wrong.
> For me it's better to have direct hands-on control.
>
> My only complaints have been the lack of a noise
> limiter and lack of a 5kHz notch filter in addition
> to the 10kHz filter.
>
> I've bookmarked your recommendations.
> Sometime I'll build one or more and report my
> experience using them vs the SE-3.  Or if anyone
> local has built one, let's get get together and try
> it out next to my SE-3.
>
> Dave Wise
> SWL in Hillsboro Oregon
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net] 
> On Behalf Of 2002tii
> Sent: Tuesday, December 22, 2009 5:06 PM
> To: r-390 at mailman.qth.net
> Subject: Re: [R-390] Best approach for SSB mod on R-390A
>
> Cecil wrote:
>
>>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....
>
> I have an SE-3 and frankly, in my view, it's not worth the time it would 
> take to toss it into the trash.  Anyone who has used a properly designed 
> synchronous detector would just laugh at it.  IMO, the esteem in which it 
> seems to be held in some quarters shows how few hams and SWLs have used a 
> properly designed synchronous detector.
>
> The SE-3 oscillator is not temperature compensated, and it drifts beyond 
> the ability of the frequency trim capacitor to center it as the 
> temperature changes.  I had to drill a hole in the top cover above the 
> tuning coil and leave a tuning tool poking out the top to tweak it.  The 
> capture and lock-in ranges and behaviors were also not well chosen, 
> necessitating that the user manually "guide" the PLL into lock.  All in 
> all, a very poor effort, IMO.  PLL design is just not that difficult.
>
> NOTE: the above comments pertain primarily to using an SE-3 as an AM 
> synchronous detector.  It's OK as a BFO/product detector, but far from 
> state of the art even for that use.  The SE-3 does not have IF filtering 
> or AGC -- it depends on the host radio for those functions.
>
> For anyone interested in constructing a properly working synchronous 
> detector, here are three of the many references you will find through a 
> web search:
>
> http://www.premium-rx.org/ref/amsynchronous.pdf
>
> http://webpages.charter.net/wa1sov/technical/sync_det.html
>
> http://www.arrl.org/tis/info/pdf/9307028.pdf
>
> Best regards,
>
> Don
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