I guess you can tell I never use CWT :>) Thanks for the tip. 73, Guy.
On Fri, Dec 3, 2010 at 8:48 AM, Bill VanAlstyne W5WVO <[email protected]> wrote: > Just one caveat on this procedure (thanks Guy!) -- make sure you have CWT > turned OFF; otherwise, SPOT will not do what you want it to. (It will > attempt to retune the VFO.) > > Bill W5WVO > > > -----Original Message----- From: Guy Olinger K2AV > Sent: Friday, December 03, 2010 13:38 > To: [email protected] > Cc: Elecraft List > Subject: Re: [Elecraft] Determining zero-beat > > Set mode to CW. Set width to 200 Hz. Do a HOLD on MON. Set level to > 20-25. Tap MON to turn off beat. Tune to 10.000.000. Tap SPOT. > Should hear a beat, albeit a slow one. Advance or retard AF gain to > get the obvious beat. In CONFIG: go to REF CAL. This will have turned > off SPOT. Tap it again. Adjust VFO A to get slowest beat. > > With some patience and careful listening this is usually clearly a > specific setting, in my case 49.379.737. You will find that the beat > frequency wavers around due to changing propagation path length so you > have to listen for a while. Having accounted for the variation in > propagation it is quite clear in my case, albeit subtle, that 738 is > too high, and 736 is too low. It is also more clearly heard at some > times of day on a given frequency than others. There are also times > where there is a fast QSB on the signal that can be confusing and you > may just have to wait until the signal steadies. When you have it > spot on, there will be periods of several seconds or more where the > beat does not vary, something which does not happen nearly as much up > or down one Hz on the REF CAL frequency. > > After this adjustment it is clear that my K3 is within +/- 0.5 Hz at > 10.000000 MHz with no drift, probably within +/- 0.2 Hz though I won't > claim that. I have the KTCXO3-1 option in mine. It may be that a K3 > without it may be a bit more cranky, I would imagine so, but I'm not > pulling it out to see :>) > > 0.5 Hz at 10 will be less than 2.5 Hz at 50, though I don't know the > formula. It's not a straight multiply because of the conversion > scheme. With this adjustment in the menu, the chief contribution of > the KTCXO3-1 is no drift, not an absolute accuracy. > > My K3 is way more accurate than they spec, and accurate enough to show > up the propagational variations in the WWV frequencies. I would think > that if you have left it on for a while, and calibrate it before an > "exercise", you can count on it for spot on. > > 73, Guy. > > On Fri, Dec 3, 2010 at 6:09 AM, Pete Smith <[email protected]> wrote: >> >> I want to use my K3 to calibrate the QS1R receiver used here as part of >> the Reverse Beacon Network. For technical reasons, it's desirable to >> calibrate the QS1R at as high a frequency as possible, so I wanted to do >> so in the 6-meter band. I thought that if I knew how accurate the K3's >> frequency display was at 10 MHz WWV, I'd know whether I needed to >> compensate for any systematic error when comparing the two up on 6M. >> >> Here's where the problem comes in. AM mode isn't usable for finding >> zero-beat, of course. On CW, it appears that the zero-beat frequency is >> displayed as 10 MHz minus the "pitch" frequency (which can only be >> adjusted down to 300 Hz). I'd like to know the frequency accuracy of >> the K3 within 20-30 Hz if possible for this exercise. >> >> How to proceed? >> >> -- >> 73, Pete N4ZR >> >> The World Contest Station Database, updated daily at >> www.conteststations.com >> The Reverse Beacon Network at http://reversebeacon.net, blog at >> reversebeacon.blogspot.com, >> spots at telnet.reversebeacon.net, port 7000 >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> 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:[email protected] > > 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:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
