Thank you very much Ian Wells ----- Original Message ----- From: "Gregg Lengling" <[EMAIL PROTECTED]> To: <Repeater-Builder@yahoogroups.com> Sent: Thursday, December 04, 2003 2:06 PM Subject: RE: [Repeater-Builder] Re: crystal alignment (how accurate is accurate)
> Another couple ways to calibrate: > > I use a GPS receiver with an 10 meg output to calibrate my service monitor. > > > Before GPS just find out if you have a TV station that is using a Rubidium > Standard for their frequency. Here in Milwaukee Ch4 uses one and we always > used it to check calibration in the field, the standard was at 67.24 MHz, a > lot better than using 10 megs....much higher order of precision. > > > Gregg R. Lengling, W9DHI, Retired > Administrator http://www.milwaukeehdtv.org > K2/100 S#3075 KX1 S# 57 > Politics is the art of appearing candid and completely open, while > concealing as much as possible. -States: The Bene Gesserit View > > > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] > Sent: Wednesday, December 03, 2003 10:04 PM > To: Repeater-Builder@yahoogroups.com > Subject: [Repeater-Builder] Re: crystal alignment (how accurate is accurate) > > Ian, you should have time standard frequencies in Australia on 5 10 and 15 > MHz. If you have a secondary receiver, tune in the 10 MHz and compare it to > the > output of the 10 MHz timebase in your service monitor. > > This has been one of my obsessions for a while now, to find a way of more > accurately setting my 10 MHz timebase in my service monitor. > > Zero beating with our WWV signal will only get you within a cycle or so. > (i.e., one cycle off at 10 MHz equals 40 hertz error at 400 MHz) And then > there's > trying to find a time when the signal is strong and doesn't fade too much. > Since I live about 50 miles south of Ft Collins you would think I would have > a > strong signal all the time, but no. > > So I figure there must be a way to use a scope to compare two audio signals > (X/Y like we do with PL tones) and be able to set it more accurately. I have > > tried comparing the 1000 cycle audio tone from an external receiver when I > generate a signal from the service monitor I kc off frequency from WWV. Then > > comparing that to the 1kc tone generated from the monitors own PL tone > generator > (phase locked to the 10 MHz time bases). You should be able to see a slow > drift > between the two on the oscilloscope but so far no success, too much noise to > > see much. > > Does someone have a way of getting closer than 1 cycle? (no I haven't bought > > a GPS timebase receiver yet but have drooled over them on Ebay. > > I've always wondered if a tuned RF receiver using 10 MHz crystals for IF > filters would give you a strong 10 MHz carrier that could be used for > calibration. > > Hopefully this is still somewhat on topic since we all need to set our > repeaters on frequency. > > Art - KC7GF > Golden, CO > > > > > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > > > > > > > > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
