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 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, external DC power inputs Etc.. has advantages in my view for Ham use.) > > I'd still want to setup some form of NTP server. > > All the usual cautions about buying used gear apply. > > Hope this is of some interesest. Others will likely have other opinions. > > All the best > Mark S > VE7AFZ > > Sent from my iPhone > >> On Dec 29, 2015, at 6:51 AM, Cash Olsen <[email protected]> wrote: >> >> 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 -- [email protected] >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
