Actually, after you posted that on the reflector last night I went back to the
P3 and I put my span at 50KHz and I did a BUNCH of QSY to and from the zero
beat of a signal. I was generally able to park myself within about 10Hz of
the Center. A quick push of the SPOT button brought me right to Zero Beat with
the signal. I did this with both weak signals and with loud ones (dark red
lines).
Of course this is ONLY because I painstakingly took the time to find and
properly set my Center mark before doing the final Ref Cal Alighment.
As you have already figured out, it's VERY important to let the P3 warm up
sufficiently due to it's excessive drifting before doing the REF-Cal alignment.
After that you should be able to get yourself somewhat close.
I think that the key to getting it so accurate, Bob, is to use your Peak
meter.. Once a signal is present on the Audio display, and you can see below
that it's a cw signal, if you line the A marker up with the displayed Peak of
the signal that's stuck there, you can pretty much nail it. If you're trying
to QSY to a signal by lining it up with only the Waterfall line as it comes
down, or even worse, by using the Audio scope WITHOUT the peak on, you'll never
get close.. That becomes a guessing game.
I'm still VERY much in favor of your idea to have a Scrub feature once you QSY,
thereby using the Select knob as a way to drag the VFO around until you have
Zero beat the signal both on the rig, and on the display. Then exit the Scub
mode returning the A/B marker.
Because the accuracy of the display readout when doing the "CENTER" alignment
is short by 2 digits, it causes the centering of the P3 to be within only 100Hz
of the actual center. It is imperative to the CW guys that the extra 2 digits
be displayed on the Top center read out. This would allow us to both CENTER
and REF CAL our WWV carrier right on Zero Beat, and not just within 100Hz.
Right now this is the most crippling blow to the CW guys.
> Date: Wed, 11 Aug 2010 10:33:27 -0600
> From: bob.cunni...@gmail.com
> To: elecraft@mailman.qth.net
> Subject: Re: [Elecraft] P3: a modest proposal for QSY
>
> Can you really do much better than +/- 100-200 Hz using a 50 kHz span?
> That requires a marker placement accuracy of +/- 2 pixels, a 4 pixel
> window, which is less than 1% of the width of the display (4/480 =
> 0.25%). If so, I must concede that you're a much better marksman than
> I am!
>
> The idea is to make life easier when cruising around the band when
> using a *wide* span. Earlier today I opened it up to 70 kHz so I could
> see +/- 35 kHz whilst listening around 7.040 Mhz and try as I might,
> when I used the marker to select a CW signal I often ended up outside
> the passband of my 400 Hz filter. At 70 kHz each pixel represents a
> 150 Hz bin (approx) so I'm off by even 2 pixels I'm outside the filter
> passband. Jumping from signal to signal within a wide panadaptor span
> would be easier with a fine tune feature, and work for SSB signals as
> well as CW.
>
> I guess I'm spoiled by using the mouse in point/click/fine tune mode
> with LP-Pan/PowerSDR-IF in a 96 kHz span where there is no need for
> extreme accuracy in pointing, it's fast and easy. I think similar
> functionality would enhance the P3, just a suggestion.
>
> "Snap Tune" is an interesting idea too.
>
> 73,
>
> Bob NW8L
>
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