Re: [Repeater-Builder] Re: crystal alignment (how accurate is accurate)

[Robert D. Mantell]

Hi Ian, Use any standard frequency transmission on any frequency ( the higher the better).  I know Japan has such transmissions, and I think India.  Do a google search for standard frequency transmissions.  You might even find what you want in VK land. 73 - Bob - W3TGG ian wells wrote: hi again bob i carnt receive any signal on 10 meg . thansk ian ----- Original Message ----- From: "ian wells" <[EMAIL PROTECTED]> To: <Repeater-Builder@yahoogroups.com> Sent: Saturday, December 06, 2003 3:33 PM Subject: Re: [Repeater-Builder] Re: crystal alignment (how accurate is accurate) ok thanks bob i will give it a go ian ----- Original Message ----- From: "Robert D. Mantell" <[EMAIL PROTECTED]> To: <Repeater-Builder@yahoogroups.com> Sent: Saturday, December 06, 2003 11:23 AM Subject: Re: [Repeater-Builder] Re: crystal alignment (how accurate is accurate) It never fails - pose a simple question, and you get a series of overly complicated answers involving expensive equipment. To calibrate a local frequency standard, one needs a short wave rx with an s meter (mechanical type), and a means of balancing the local standard signal level with that of WWV at 10 MHz. All you need to do is adjust the local standard while watching the s meter. As it is adjusted, you will notice the s meter flutter at a decreasing rate as you reach 10 Mhz. When you are dead on, the s meter will drift slower and finally stop. You are there. And please, do not argue about doppler, selective fading, etc. Sure you will be able to see these effects, but they will not affect the accuracy of this operation. Just watch for the response when the WWV or whatever signal is steady. I hope this helps Bob - W3TGG [EMAIL PROTECTED] wrote: 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/ Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.