[Elecraft] SSB Filters

Tue Feb 26 07:13:00 2002

Ron: Now you've got me wondering what damage I might have done to CW. =
Any way to measure the S/N at my current setting? I could then peak it =
and see what I'd lost. If it's just db between that birdie at 7mhz and =
the noise floor, I can take that number off Spectrogram. Might need a =
little amplification to get a good reading.

I'd like to know what the SSB audio cost me on CW.

Dan

-----Original Message-----
From: Ron D' Eau Claire [mailto:[email protected]]
Sent: Monday, February 25, 2002 10:33 PM
To: Dan Barker
Subject: RE: [Elecraft] SSB Filters

True enough, Dan.

The "flattening mod" was more for receive than transmit. My K2 sounded
absolutely tinny on one sideband and bassy on the other until I put it =
in. I
was able to get it "flat" by adjusting the coil, but that really =
compromised
the signal/noise ratio on CW. That's when Wayne or Eric came up with the
transistor switch mod.

I suspect the need for it varies a bit with each radio, since these =
filters
are made up of discrete xtals.

I wanted to know because next time someone asks about the weird SSB =
audio on
the reflector, I'll suggest that they consider doing what you did as =
well.

Thanks,

Ron AC7AC

> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Dan Barker
> Sent: Monday, February 25, 2002 7:15 PM
> To: Elecraft
> Subject: [Elecraft] SSB Filters
>
>
> Ron:
>
> You are absolutely right, it's just build the thing, and remove
> the 10 pf cap, and twist some knobs (one LARGE, several small). I
> read about the "flattening mod", but the Spectrogram came out so
> nice without it, I don't really see the need. The guys on the
> receiving end don't seem to hear the need either<g>.
>
> My rig is stock except for the sidetone cleanups (not very clean,
> but at least better) and C180 being pulled. The "trick" was not
> to worry that my numbers were so very far from the examples (like
> 400-600 Hz) in the book and in diddling L34 by eye, not ear.
>
> Dan / WG4S / K2 #2456
>
> -----Original Message-----
> From: Ron D' Eau Claire [mailto:[email protected]]
> Sent: Monday, February 25, 2002 8:20 PM
> To: Dan Barker
> Subject: RE: [Elecraft] SSB Filters
>
>
> Hi Dan:
>
> By your description of removing C180, I take it you did not put
> the "filter
> flattening" mod in that is provided as an Application Note on the =
Elecraft
> Reflector.
>
> Just curious, because you managed to get a very nice looking response
> without it if that's so.
>
> Wayne/Eric announced almost two years ago that the mod would
> become part of
> the r-f board in future releases, but I've not yet seen it hit the =
street.
> They may have re-thought the idea.
>
> Ron AC7AC
> K2 # 1289
>
> > -----Original Message-----
> > From: [email protected]
> > [mailto:[email protected]]On Behalf Of Dan Barker
> > Sent: Monday, February 25, 2002 2:40 PM
> > To: Elecraft
> > Cc: Steve & Anne Ray
> > Subject: [Elecraft] SSB Filters
> >
> >
> > Failing miserably to get my K2 sounding right on my own, I
> > grabbed the telephone and called Elecraft. I had LSB sounding OK,
> > and USB off in left field. None of my numbers were within 400 Hz
> > of the "book" values. Gary said that was fine.
> >
> > Gary talked me through the procedure for a K2 with recent
> > firmware and the KSB2 adapter installed.
> >
> >  a) Bend C180 back and forth until it breaks off, and discard.
> >  b) Fire up Spectrogram; and set a marker at 400 and 2200 Hz.
> >  c) Move the FL1 BFO freq. until it's balanced between the marks.
> >  d) Repeat for the other sideband.
> >  e) Diddle L34 to flatten the top of the USB response, but not so
> > far as to screw up the LSB response.
> >  f) Repeat centering the response curves if necessary.
> >
> > My results below:
> >
> >       USB
> >
> >   Picture suppressed on reflector, see
http://www.visioncomm.net/ssb.html
>
>       LSB
>
>   Picture suppressed on reflector, see =
http://www.visioncomm.net/ssb.html
>
> I just spend about an hour on SSB with Steve in GA, and he says
> both Sidebands sound FB, and the same. Cool!
>
> So, what's this about a flattening mod? Doesn't really look like
> one is needed.
>
> Dan / WG4S / K2 #2456, KAT2, K160RX, KIO2, KSB2
>
> PS: Now, How do I get on PSK? The MH2 ain't gonna cut it! I'm a
> gonna need some WIRE! (who ever called this hobby wireless? -
> They're nuts!).
>
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