Bob, Please advise the make & model of your counter, and if possible, the make & model of the OCXO it contains, or if you have the manual, the aging spec on the time base. It's entirely possible (probable) that the OCXO is already several orders of magnitude better than any HF WWV broadcast. BTW, higher frequency broadcasts are much more susceptible to atmospheric shifts than lower frequencies. That's why WWVB at 60KHz was used for many years as a traceable standard. How long has it been since its last real calibration (not beating against WWV, but properly calibrated)? I agree with the others who have advised in favor of a GPSDO. A second approach would be a Rubidium standard. Much more stable than a stand-alone OCXO, and they don't need an antenna. But, you would need to be assured that it's properly calibrated when you buy it. Ebay seller rdr-electronics sells Rb oscillators, and I'm pretty sure those they sell are properly calibrated before they ship them out. Good folks. Since you live in the LA area, surely there are other hams in the area who have the ability to properly adjust the time base in your counter. Get on the air and ask around. Might be someone just a couple of blocks away who has all you need.
Cheers, Dave M ----- Original Message ----- From: "Bob Albert via time-nuts" <[email protected]> To: "Discussion of precise time and frequency measurement" <[email protected]> Cc: "Bob Albert" <[email protected]> Sent: Saturday, January 26, 2019 12:06:43 AM Subject: Re: [time-nuts] Frequency standard Paul, thanks for your reply. You ask what I want to accomplish. Basically I just want to be able to calibrate the OCXO in my counter. I don't get a good enough signal from WWV and don't really have a proper method for adjustment. I listen to the highest froquency WWV I can hear, and these days it's probably only 10 MHz. I listen on a communications receiver to my counter and to WWV beating. As I watch the S meter, the pulsing gets slower and slower as I zero in, and at some point the pulsing is lost because the atmospheric fading masks it. That's usually around one fade every couple of seconds, for an accuracy of only about 1 part in 20 million. I want it somewhat better, but no way do I need it 100 times better. If I could set it within 0.1 Hz that would be fine - it would enable frequency measurement at 100 MHz with pretty good confidence, less so at 500 MHz. I used to be able to hear 20 and 25 MHz from WWV but those days are gone. Even then, the confidence level is a bit poorer than I'd like. So maybe a GPSDO would help but it seems the cost is out of proportion to my needs. Bob On Friday, January 25, 2019, 9:01:59 PM PST, paul swed <[email protected]> wrote: Bob The gpsdos will be far superior to the method you are currently using. I will guess 100-1000 times better and higher. I took a quick look at EBAY boy there are lot of them these days. We all have our favorites. Trimbles, HPs... But what would help is understanding your need. What do you want to accomplish. Regards Paul WB8TSL On Fri, Jan 25, 2019 at 9:05 PM Bob Albert via time-nuts < [email protected]> wrote: > Please excuse my ignorance but I have been trying to improve on my > frequency calibration. > I have always used WWV but when I try to get really close in frequency, > the beat and the fading are difficult to separate. > Someone suggested I get a GPSDO to refine my 10 MHz. I looked around and > have seen a few, mostly in the $100 range, but before I shell out fot > something I know little about I wonder if someone can give me a short > tutorial or at least some advice on what I need to do. > I live in Los Angeles so I imagine signals would be reasonably strong. > But what hardware and software do I need? I want 10 MHz to put into my > counter or, at least, to calibrate the time base in the counter. I prefer > the latter, since that means I won't have to receive GPS signals in order > to measure frequency. Most of the time I don't need really accurate > results. > I could run an outdoor antenna if needed. What receiver ought I look > into, how much budget do I need, and all the other questions relating to > this subject. > And finally, how much frequency error can I expect? > Bob _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
