Bill, I'm going to try to be as least condescending as I can. Please forgive me if I go astray. I tend to get very snippety when I'm being treated as if I'm dumb... Before you can even begin to set the Ref-Cal on the P3 you must FIRST know that the center line on the P3 is actually the center of the Freq. it is displaying. I'm sure by seeing your answer to my email that this is something that has completely alluded you. What you are suggesting, and the manual for that matter, is that what ever the display says is the center Freq. is going to be an accurate reading. This is just plain and outright ridiculous. If you have taken the time to really think about what is going on here you would come to the realization that there is only 1 ONE digit after the KHz freq. display on the P3 Center line (IE 10.000.0) If you look at the centering adjustment for the P3 you will notice that the display will NOT change from the 10.000.0 position until you reach the 10.000.1 (+100Hz) or 9.999.9 (-100Hz) frequency. Therefore logic dictates that if you try to adjust a center and just arbitrarily use any position between 10.000.1 and 9.999.9 as your center you have a 1 in 100Hz chance of being centered on the Zero beat of WWV in this case (10.000.000 being the center carrier freq. of wwv in the USA. Not 10.000.099). In other words, this means that if you were to even attempt to adjust your Ref-cal alignment on the P3 before finding the best "FUZZY" center of 10.000.000 you can, your REF-CAL alignment will NEVER be closer than the center you have set it to. So, now adding both the complete inaccuracy of the "Center alignment" of up to 100Hz, and the best possible marker accuracy of 5Hz (in the 2KHz span), you can NEVER set the P3 closer than 5Hz with any actual accuracy. And That of of course would require you making a really really good guesstimation of where the Fuzzy Center on the P3 is by finding the highest number before the flip, and the lowest number before the flip from 10.000.0, then moving the select knob to as close a center of each as you can. Would you put your K3 on 10.000.0, turning off the extra 2 digits and try to set your Config: Ref-Cal alignment to Zero beat WWV? Because this is exactly what you are suggesting others do by telling them that the "Center" alignment has nothing to do with the Ref Cal alignment on the P3. Elecraft has GOT TO add those two other digits into the display if anyone is going to have an accurate centering of their P3 before they do the Ref Cal alignment. This is IMPERATIVE to the CW operator that relies on being able to use 50Hz wide filters. This is forgetting the fact that on 3 of the units I have helped align so far they have ALL been off frequency with both Center and Ref Cal by as much as -300. Well, -160 when first turned on, -220 about a half hour later, and then -300 about an hour later. The drift is incredible on the P3, a .05 or even 1ppm crystal it does not have. I would suggest to EVERYONE that has the P3 they wait AT LEAST and hour (assuming you generally use your P3 for more than an hour when you operate it on a normal day) before setting their REF Cal alignment. But without doubt, before you do that, make sure that you know the center mark on your P3 is actually the center you're looking for. I think it's time for the manual to change how the alignment has been written, not how I'm doing my alignment. Thank you.
> Date: Wed, 11 Aug 2010 12:08:04 -0700 > From: btipp...@alum.mit.edu > To: elecraft@mailman.qth.net > Subject: Re: [Elecraft] P3: a modest proposal for QSY > > > > The Smiths wrote: > > > > 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. > > > > You may not be doing Reference Calibration correctly if you are using the > digital frequency readout on the P3. You don't need anything except the > Spectrum display (step 5 below). From page 19 of the manual: > > Frequency Calibration > > Turn on the transceiver and P3 and allow > them to warm up for 30 minutes, minimum, > before performing the calibration. > > 1. If the transceiver has a calibration procedure to > correct its frequency errors, perform that > procedure first. > > 2. Using a well-calibrated signal generator or an > on-the air carrier signal of known frequency, > tune in the signal on the transceiver. An A.M. > broadcast station can serve as a suitable test > signal. > > 3. Adjust the transceiver frequency to the known > frequency of the test signal. Depending upon > the modulation mode of the transceiver, the > signal may not be audible. > > 4. Set the P3 for minimum span and adjust the > reference level and scale so you can easily see > the signal. > > 5. Select MENU:Ref Cal, tap the SELECT > knob, and adjust the frequency calibration until > the carrier is centered horizontally on the > display. If the required correction is more than a > few kHz, it may be that the I.F. frequency is set > incorrectly. That can be adjusted via > MENU:Xcvr Def. > > The P3's Ref Cal steps in the menu are 10 Hz but that's close enough for > accurately QSYing to even a 50 Hz bandwidth. > > 73, Bill > > -- > View this message in context: > http://elecraft.365791.n2.nabble.com/P3-a-modest-proposal-for-QSY-tp5410950p5413530.html > Sent from the [K3] mailing list archive at Nabble.com. > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
