Thank you verymuch Ian Wells ----- Original Message ----- From: "Rod Lane" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Thursday, December 04, 2003 2:55 PM Subject: RE: [Repeater-Builder] Re: crystal alignment (how accurate is accurate)
> Used to be... In the good old days before frame syncs, you could wait > until the local affiliate was in network programming and you had a REAL > good 3.58 reference. Not so anymore. 3.579545 was an easy number to > remember for some reason... ;^) > > 73 de N1FNE > > -----Original Message----- > From: Gregg Lengling [mailto:[EMAIL PROTECTED] > Sent: Wednesday, December 03, 2003 11:07 PM > To: [email protected] > 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: [email protected] > 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/ > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
