[Elecraft] P3: a modest proposal for QSY

[Bob Cunnings]

Good advice, I'll try enabling Peak and see if I can line the marker
up better that way.

Bob NW8L

On Wed, Aug 11, 2010 at 11:04 AM, The Smiths <notforchat at hotmail.com> wrote:
> 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.cunnings at gmail.com
>> To: elecraft at 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
>>
>