Re: [time-nuts] Abstract for consideration at 2016 New Mexico TechFest
Thanks for correction Will On 30/12/15 17:12, Bill Byrom wrote: > I believe you meant a BC-221 frequency meter, which was a very good > instrument when introduced over 70 years ago:. > http://radionerds.com/index.php/BC-221 > http://www.orionsword.net/Electronics/TestEquipment/ZenithFreqMeter/BC221.html > > Back in the early 1970's I took my BC-221 and added a TTL divide by > 1,000 (or 2,000 or 4,000 or 8,000) external circuit to generate very > precise audio test tones from the RF oscillator. The BC-221 had two > output frequency ranges: LOW: 125 to 250 kHz HIGH: 2 to 4 MHz > > By using the appropriate range and divide ratio I could generate 15.625 > Hz to 4 kHz (and multiples) with very smooth continuous tuning and great > accuracy (typically better than 0.005%). This was very useful for > adjusting and measuring audio filters and circuits, such as 2125/2295 Hz > AFSK terminal units I was using on 2 Meter AM and with SSB rigs for HF > FSK. I could tune up my filters built with 88 mH telephone surplus > toroidial inductors. I could also use the audio source to compare by ear > the beat note between harmonics of my divided-down 5 MHz commercial > surplus precision oven oscillator and RF signals (such as during the > ARRL Frequency Measuring Test). > > The anti-backlash gear mechanism, large dial with high resolution > interpolation scale, and well-built variable capacitor were difficult to > find in other commonly available radio related equipment. In my opinion > the BC-221 was a technically beautiful precision instrument. It was the > time-nuts tool of choice for several decades! > -- > Bill Byrom N5BB > > > > On Tue, Dec 29, 2015, at 08:12 PM, Will wrote: >> >> That sure beats a BC21 that many hams (and Post Office Techs) used long >> ago. >> >> So long ago Google doesn't want to help and memory has faded over half >> a century. >> >> Cheers, >> Will >> > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Abstract for consideration at 2016 New Mexico TechFest
I believe you meant a BC-221 frequency meter, which was a very good instrument when introduced over 70 years ago:. http://radionerds.com/index.php/BC-221 http://www.orionsword.net/Electronics/TestEquipment/ZenithFreqMeter/BC221.html Back in the early 1970's I took my BC-221 and added a TTL divide by 1,000 (or 2,000 or 4,000 or 8,000) external circuit to generate very precise audio test tones from the RF oscillator. The BC-221 had two output frequency ranges: LOW: 125 to 250 kHz HIGH: 2 to 4 MHz By using the appropriate range and divide ratio I could generate 15.625 Hz to 4 kHz (and multiples) with very smooth continuous tuning and great accuracy (typically better than 0.005%). This was very useful for adjusting and measuring audio filters and circuits, such as 2125/2295 Hz AFSK terminal units I was using on 2 Meter AM and with SSB rigs for HF FSK. I could tune up my filters built with 88 mH telephone surplus toroidial inductors. I could also use the audio source to compare by ear the beat note between harmonics of my divided-down 5 MHz commercial surplus precision oven oscillator and RF signals (such as during the ARRL Frequency Measuring Test). The anti-backlash gear mechanism, large dial with high resolution interpolation scale, and well-built variable capacitor were difficult to find in other commonly available radio related equipment. In my opinion the BC-221 was a technically beautiful precision instrument. It was the time-nuts tool of choice for several decades! -- Bill Byrom N5BB On Tue, Dec 29, 2015, at 08:12 PM, Will wrote: > > That sure beats a BC21 that many hams (and Post Office Techs) used long > ago. > > So long ago Google doesn't want to help and memory has faded over half > a century. > > Cheers, > Will > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Abstract for consideration at 2016 New Mexico TechFest
That sure beats a BC21 that many hams (and Post Office Techs) used long ago. So long ago Google doesn't want to help and memory has faded over half a century. Cheers, Will On 30/12/15 09:45, Mark Spencer wrote: > Hi Cash. > > Here is a bit of a narrative and some comments from an amateur radio > perspective. > > I got into the time nuts hobby as off shoot from amateur radio. I was using > a pc sound card to evaluate the frequency stability of some of my ham radios > by looking at the change in "beat note" when receiving wwv in SSB mode. > > I realized that I couldn't use wwv as a frequency standard due to Doppler > shift and in practice my radios with tcxo's were stable enough that it wasn't > clear if I was seeing Doppler shift from wwv or the radios drifting. > > After some research I purchased a gpsdo from James Miller G3RUH which > provided a suitable frequency source to replace wwv for my purposes. Later > I wanted to see accurate that GPSDO was. To make a long story short > > Ended up buying half a dozen HP5370 and HP5335 time interval counters a > Jackson labs fury GPSDO, two Z3805 GPSDO's, a thunderbolt, a BVA, a FTS1050, > an HP105, two time source 2700's (with prs 10 rb's) various stand alone rb's, > ocxo's, various HP5328 counters with 10811 ocxo's, an NTP server etc. > > Wrote some scripts using Ulrich's plotter software to log the data to text > files and processed the data using John's time lab software (thanks !). > > Couldn't quite convince my self to buy a cesium standard and a time pod > (figured I would end up wanting to get two or three of each once I started > down that road.) > > I was (and am) more than satisfied with the performance of the G3RUH GPSDO > for my amateur radio activities. > > At the time work involved long periods of travel so collecting data for a few > weeks at a time then looking at it later worked out ok. Later I also had > little time or interest for Amateur radio due to travel. > > After a few years I decided to get back into amateur radio. I still use the > G3RUH gpsdo to check the frequency of my VHF and up gear. It works well for > this as it produces useable harmonics to over 1.3 GHz and it runs from a 13.8 > volt power source. From time to time I still compare the G3RUH GPSDO to my > other references. > > I have found for VHF and up weak signal work it is very helpful to have a > suitable frequency standard. > > Regarding frequency calibration of my radios. In practice listening to > harmonics from the G3RUH GPSDO with the radio set to SSB mode and looking at > the resulting audio frequency works well for me. So far I've resisted the > temptation to modify my radios to accept an external frequency reference, but > checking their accuracy prior to use is part of my setup routine. I suspect > at some point I'll acquire radios that need an external reference source. > I've ear marked a few ocxo's for this purpose. > > Time synchronization is also important for some of the weak signal modes and > having my own NTP server is helpful. > > For amateur radio use (with some time nuts interest) two GPSDO's, a decent > time interval counter and a frequency counter capable of measuring > frequencies of interest (and able to accept an external frequency reference) > along with a PC with a sound card is probably a good starting point IMHO. A > solution for time synchronization is also worth having especially for > operations in locations without Internet connectivity. A GPSDO with a one > pps output can help facilitate this. > > In terms of hints. > > Quality double shielded cables are useful. Conversely cheap cables caused > me various problems. > > Terminating un used connections is also helpful. > > A decent oscilloscope is useful for viewing wave forms and looking at signal > levels. > > In my experience getting the most performance out of gear such as the HP5370 > requires attention to detail re signal levels and trigger set points. A > selection of attenuators and a decent scope is helpful. > > I also found using the BVA as the clock source for the HP5370's was helpful > (vs using the built in 10811's.) > > The prologix gpib to Ethernet adapters worked well for me. > > If I was doing it again on a budget for ham radio use: > > I'd probably still buy the G3RUH GPSDO, along with one other GPSDO. > > I'd probably pass on the HP5370 series counters and look for a used HP53132 > counter and buy a dedicated frequency counter for measuring RF frequencies. > (I have no personal experience yet with the HP 53132 but it seems to be well > regarded.) > > I believe the HP5370's are getting a bit long in the tooth now. I bought > four working used ones and now have two that are fully functional. I expect > I could get at least one more working if tried. I also needed a special > pulse generator for the alignment procedure. I picked up at least one of > those as well. In hin
Re: [time-nuts] Abstract for consideration at 2016 New Mexico TechFest
Hi Cash, My interest in time and frequency measurement goes way back when I was just out of high school and was employed by a few local radio stations. We were charged with ensuring the station frequency was within the FCC limits. I remember receiving the report from our external frequency referance "expert" every month. "Northwest Frequency Monitoring" (or something like that). He flew around the Western US in his Piper Aztec taking frequency measurements for radio and TV stations. This was 1965 or so. I would then compare his readings with my own HP-117A, VLF Frequency Comparator at 60 KHz. A few years later there was an article published in 73, magazine (I think) that described using the 3.58 MHz color burst frequency from local TV stations (when they had a network feed) which one could use to phase lock oscillators etc. A Rubidium standard was out of the question at that time. Then along came Brook Shera's neat little GPS frequency standard. That's about the time the telecom industry was removing from service the HP Z3801A GPSDO's. I bought several of them at $285 each and thought that was a bargain. I still have one that distributes a 10 MHz signal throughout my lab with an HP 5087A Distribution Amp configured for 5 and 10 MHz output. A few years later I became interested in EME (earth-moon-earth) operation as well as roving on the microwave bands. I was fortunate to operate (in 2009) the Stanford University's 145 foot dish operated and maintained by SRI. We operated 1296 MHz and used a Rb for phase locking the radio although that really wasn't necessary at that frequency and mode. It wasn't very long ago that the market was flooded with 10 MHz Rb's that could be had for $60 or less. I think that market has dried up now. I operate on the microwave bands up through 24 GHz. Without phase locking the transverter's onto a very good standard, it's very difficult to make contacts on the upper bands (10 and 24 GHz). I use G3RUH's fine GPS DO for generating the 10 MHz reference as well as a Jackson Labs GPSDO. Dave - W6TEARRL Technical CoordinatorAMSAT Area Coordinator > From: m...@alignedsolutions.com > Date: Tue, 29 Dec 2015 12:45:32 -0800 > To: time-nuts@febo.com > Subject: Re: [time-nuts] Abstract for consideration at 2016 New Mexico > TechFest > > Hi Cash. > > Here is a bit of a narrative and some comments from an amateur radio > perspective. > > I got into the time nuts hobby as off shoot from amateur radio. I was using > a pc sound card to evaluate the frequency stability of some of my ham radios > by looking at the change in "beat note" when receiving wwv in SSB mode. > > I realized that I couldn't use wwv as a frequency standard due to Doppler > shift and in practice my radios with tcxo's were stable enough that it wasn't > clear if I was seeing Doppler shift from wwv or the radios drifting. > > After some research I purchased a gpsdo from James Miller G3RUH which > provided a suitable frequency source to replace wwv for my purposes. Later > I wanted to see accurate that GPSDO was. To make a long story short > > Ended up buying half a dozen HP5370 and HP5335 time interval counters a > Jackson labs fury GPSDO, two Z3805 GPSDO's, a thunderbolt, a BVA, a FTS1050, > an HP105, two time source 2700's (with prs 10 rb's) various stand alone rb's, > ocxo's, various HP5328 counters with 10811 ocxo's, an NTP server etc. > > Wrote some scripts using Ulrich's plotter software to log the data to text > files and processed the data using John's time lab software (thanks !). > > Couldn't quite convince my self to buy a cesium standard and a time pod > (figured I would end up wanting to get two or three of each once I started > down that road.) > > I was (and am) more than satisfied with the performance of the G3RUH GPSDO > for my amateur radio activities. > > At the time work involved long periods of travel so collecting data for a few > weeks at a time then looking at it later worked out ok. Later I also had > little time or interest for Amateur radio due to travel. > > After a few years I decided to get back into amateur radio. I still use the > G3RUH gpsdo to check the frequency of my VHF and up gear. It works well for > this as it produces useable harmonics to over 1.3 GHz and it runs from a 13.8 > volt power source. From time to time I still compare the G3RUH GPSDO to my > other references. > > I have found for VHF and up weak signal work it is very helpful to have a > suitable frequency standard. > > Regarding frequency calibration of my radios. In practice listening to > harmonics from the G3RUH GPSDO with the
Re: [time-nuts] Abstract for consideration at 2016 New Mexico TechFest
Hi Cash. Here is a bit of a narrative and some comments from an amateur radio perspective. I got into the time nuts hobby as off shoot from amateur radio. I was using a pc sound card to evaluate the frequency stability of some of my ham radios by looking at the change in "beat note" when receiving wwv in SSB mode. I realized that I couldn't use wwv as a frequency standard due to Doppler shift and in practice my radios with tcxo's were stable enough that it wasn't clear if I was seeing Doppler shift from wwv or the radios drifting. After some research I purchased a gpsdo from James Miller G3RUH which provided a suitable frequency source to replace wwv for my purposes. Later I wanted to see accurate that GPSDO was. To make a long story short Ended up buying half a dozen HP5370 and HP5335 time interval counters a Jackson labs fury GPSDO, two Z3805 GPSDO's, a thunderbolt, a BVA, a FTS1050, an HP105, two time source 2700's (with prs 10 rb's) various stand alone rb's, ocxo's, various HP5328 counters with 10811 ocxo's, an NTP server etc. Wrote some scripts using Ulrich's plotter software to log the data to text files and processed the data using John's time lab software (thanks !). Couldn't quite convince my self to buy a cesium standard and a time pod (figured I would end up wanting to get two or three of each once I started down that road.) I was (and am) more than satisfied with the performance of the G3RUH GPSDO for my amateur radio activities. At the time work involved long periods of travel so collecting data for a few weeks at a time then looking at it later worked out ok. Later I also had little time or interest for Amateur radio due to travel. After a few years I decided to get back into amateur radio. I still use the G3RUH gpsdo to check the frequency of my VHF and up gear. It works well for this as it produces useable harmonics to over 1.3 GHz and it runs from a 13.8 volt power source. From time to time I still compare the G3RUH GPSDO to my other references. I have found for VHF and up weak signal work it is very helpful to have a suitable frequency standard. Regarding frequency calibration of my radios. In practice listening to harmonics from the G3RUH GPSDO with the radio set to SSB mode and looking at the resulting audio frequency works well for me. So far I've resisted the temptation to modify my radios to accept an external frequency reference, but checking their accuracy prior to use is part of my setup routine. I suspect at some point I'll acquire radios that need an external reference source. I've ear marked a few ocxo's for this purpose. Time synchronization is also important for some of the weak signal modes and having my own NTP server is helpful. For amateur radio use (with some time nuts interest) two GPSDO's, a decent time interval counter and a frequency counter capable of measuring frequencies of interest (and able to accept an external frequency reference) along with a PC with a sound card is probably a good starting point IMHO. A solution for time synchronization is also worth having especially for operations in locations without Internet connectivity. A GPSDO with a one pps output can help facilitate this. In terms of hints. Quality double shielded cables are useful. Conversely cheap cables caused me various problems. Terminating un used connections is also helpful. A decent oscilloscope is useful for viewing wave forms and looking at signal levels. In my experience getting the most performance out of gear such as the HP5370 requires attention to detail re signal levels and trigger set points. A selection of attenuators and a decent scope is helpful. I also found using the BVA as the clock source for the HP5370's was helpful (vs using the built in 10811's.) The prologix gpib to Ethernet adapters worked well for me. If I was doing it again on a budget for ham radio use: I'd probably still buy the G3RUH GPSDO, along with one other GPSDO. I'd probably pass on the HP5370 series counters and look for a used HP53132 counter and buy a dedicated frequency counter for measuring RF frequencies. (I have no personal experience yet with the HP 53132 but it seems to be well regarded.) I believe the HP5370's are getting a bit long in the tooth now. I bought four working used ones and now have two that are fully functional. I expect I could get at least one more working if tried. I also needed a special pulse generator for the alignment procedure. I picked up at least one of those as well. In hindsight I'd probably settle for a bit less performance in return for (hopefully) less hassle and buy newer Hp 53132's. Not sure I'd bother with the ocxo's, rb's etc until I had a definite need for that type of gear. Doubt I'd ever buy a BVA for amateur radio use but I believe a clean FTS1050 would be worthwhile if the price was right. (The packaging, battery backup system, ext
[time-nuts] Abstract for consideration at 2016 New Mexico TechFest
Comments and critique are welcome and encouraged. Input for the actual paper from HAMS and / or time-nuts regarding current projects will be much appreciated. Time-nuts members might wish share personal anecdotes of how they got started being a time-nut, or got started working with WWVB, GPS, or GPSDO. Some of the old timers may remember the Shera project and can share comments about it. I'd like to have inputs by this Thursday for final abstract submission deadline on Friday 1 January 2016. Presentation is in Albuquerque, NM on February 27, 2016. DRAFT-DRAFT-DRAFT A High Quality Time and Frequency Laboratory on a Budget By S. Cash Olsen KD5SSJ Following a brief retrospective look at time synchronization and frequency syntonization by various methods, this paper will recall the seminal publication of Brooks Shera W5OJM (SK) in QST magazine in 1998 which introduced many amateurs to time and frequency measurement based on the Global Positioning System (GPS). Low cost and high quality GNSS (Global Navigational Satellite System, the USA DoD subset is GPS and will be used generically in this paper) receivers have spawned many recent and current projects by HAMS, world wide, to discipline both quartz and atomic (rubidium) oscillators. With amateur projects as varied as weak signals (such as QRSS, WSJT, EME) and microwave mountain topping to synthetic aperture and steered arrays of antennas, frequency coordination and time synchronization are of great importance to many Amateur Radio enthusiasts. This paper will offer technical insight into the methods and techniques for equipping a very high quality time and frequency laboratory on an amateur's budget, approximately the cost of a used transceiver. Attention will be given to the distinction between frequency (FLL) and phase (PLL) lock loops, sawtooth correction of 1PPS signal from GPS, distribution of reference oscillators and timing signals, Four Channel Dual Mixing methods, Time Interval Counters, as well as, tips and tricks to maintain high accuracy in measurements. Briefly, I will show how this subject speaks directly to the charter of the Amateur Radio Service, Part 97.1 (b)(c)(d)(e). DRAFT-DRAFT-DRAFT -- S. Cash Olsen KD5SSJ ARRL Technical Specialist ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
