Re: [time-nuts] Vintage Frequency Measurement

Hi, With low-pass filters, I think. This is the simplest method: an rc filter and measure is done on the capacitor poles. Ilia. On 02/12/17 06:08, Scott Stobbe wrote: I was inspired recently coming across a Lampkin 105 frequency meter, as to how frequency measurement was done before

Re: [time-nuts] Vintage Frequency Measurement

Back in the early sixties I worked in a lab adjusting filters for line transmission. We had numerous oscillators, built to be boat anchors, and CROs set up for X-Y display. The lab had 100hz, 1kHz, 10kHz standards wired in. We were expert at recognising lisajou figures. We might have several

Re: [time-nuts] Vintage Frequency Measurement

First you need a standard, a crystal oscillator.  If you want serious precision, you'd have one in an oven.  Zero beat that with WWV.  Then make a very stable VFO and calibrate the harmonics against the crystal.  Assume linear calibration on the VFO between check points. The military LM and

Re: [time-nuts] Vintage Frequency Measurement

In a word,Wavemeters. Classic US onwas the BC221 with built in 100kHz crystal calibrator http://radionerds.com/index.php/BC-221 British was the "Class D"http://www.royalsignals.org.uk/photos/classDno1.htm For UHF and Microwave it was Lecher lines or cavity wavemeters. Robert G8RPI. From:

Re: [time-nuts] Vintage Frequency Measurement

[Hopefully this time my post is in the required plain-text format!] The solid-state HP-5210A and its vacuum-tube predecessors, the HP-500A/B/C family, were analog frequency measuring instruments. The circuitry summed the input frequency (converted into pulses) and generated an analog voltage

Re: [time-nuts] Vintage Frequency Measurement

There was also one generator which you could tune to beat the frequency in question the generator was a frequency synthesizer without any digital part that was the famous Schomandl FD! see here SCHOMANDL-FD1-FDM1 FREQUENCY METER,

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

Could you do all three tests in parallel? One unit under test driving three counters. Each counter using a different reference signal, one on a OCXO, one on a rubidium, and one on a GPS disciplined oscillator. At each point in time during the test simply choose the one that gives the best

Re: [time-nuts] Vintage Frequency Measurement

Hi Counters go back at least into the early 1950’s. I started out with fully vacuum tube (except for diodes) counters obtained as surplus in the mid 1960’s. They used some odd gas filled triodes. Everything in them could have been on the market in 1947. They were not a common thing until the

Re: [time-nuts] Vintage Frequency Measurement

Look at (Singer) Gertsch Frequency Meter. This was standard measuring equipment in our (spectroscopy) lab in 1975. Mike -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Neville Michie Sent: Sunday, February 12, 2017 05:20 To: Discussion of precise time

Re: [time-nuts] Vintage Frequency Measurement

On 2/11/2017 10:08 PM, Scott Stobbe wrote: I was inspired recently coming across a Lampkin 105 frequency meter, as to how frequency measurement was done before counters. Certainly zero-beating a dial calibrated oscillator, would be one approach. Google BC-221 and you may get some idea of how

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

Hi You likely need to do this with something like a TimePod to get the resolution. Setting up three of them (or anything similar) is going to cost you way more than the Rb. If you have a 100 ps counter, you will get 1x10^-10 at 1 second for ADEV data. That will go to 1x10^-11 at 10 seconds

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

That is an interesting suggestion (thanks), and would indeed work for me if it is possible to split the DUT signal into 3 signals in a such a way that wouldn't affect measurements for ADEV, TDEV, MTIE. But I'm thinking anything active would introduce it's own noise into the signal and change

Re: [time-nuts] Vintage Frequency Measurement

Hi Maybe I’ve been wrong for the last many decades … To me a wave meter is a tuned circuit device that tells you the frequency by a resonance peak. They are a very common old school item for microwave frequency measurement in a teaching setting.

Re: [time-nuts] u-blox NEO-M8T GPS initial tracking test

On Sat, Feb 11, 2017 at 4:31 AM, MLewis wrote: > With this NEO-M8T, I've even turned off everything but min=4/max=8 for GPS & > GLO, and it won't accept any configuration for Galileo, let alone enable. > And that's with the required NEMA of 4.1. What firmware version are

Re: [time-nuts] Vintage Frequency Measurement

A more accurate way to adjust for zero beat is to tone modulate one of the signals. The waxing and waning of the tone is easier to discern than for the background noise. "Accurate Zero Beating, another perspective. When trimming an oscillator so it or one of its harmonics zero beats with WWV

Re: [time-nuts] Vintage Frequency Measurement

Also Motorola and Schomandl had similar instruments-I have one of the latter here I'm still trying to get a replacement meter for. The Gertsch and Motorola instruments were very similar to look at but not identical. The Schomandl was distinctly different with its tall vertical design. DaveB,

Re: [time-nuts] Vintage Frequency Measurement

I am surprised no-one mention the 3-beat method, which was fairly common for Hams with comms receivers. You put the BFO on and adjusted so the main slow beat modulated the level of the output tone. You can judge zero beat to much better than 0.1Hz that way probably near as low as 0.01Hz. (1E-9

Re: [time-nuts] u-blox NEO-M8T GPS initial tracking test

This behavior is described in the document: u-blox 8/M8 Firmware v 3.01 for Standard Precision GNSS, Release Notes This document says, among other things,: "New multi-GNSS messages use UTC as

Re: [time-nuts] Vintage Frequency Measurement

To put BC-221 things in perspective, the 1 Mc/s reference crystal was adjusted, according to the manual, to within 5 c/s... Things have come a ways since! Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] u-blox NEO-M8T GPS initial tracking test

On 12/02/2017 1:50 PM, Pete Stephenson wrote: What firmware version are you using? Are you sure it's an authentic u-blox receiver? There's a bunch of fakes out there that identify as u-blox but lack some functionality. I recently purchased an M8T and the UBX-MON-VER message shows the firmware

Re: [time-nuts] Vintage Frequency Measurement

Hi Dan yes that is 5e-6 about all an unstabilised (temp) AT could hold for any period. I guess there were no WWV or MSF signals around then. When a good source was available off-air it was possible to do better than that. In service it was probably "dont waste time trying to better the minimum

Re: [time-nuts] u-blox NEO-M8T GPS initial tracking test

On 12/02/2017 6:49 PM, David Witten wrote: Is this perhaps the reason this firmware is marked "Not for Timing Use"? The 2.01 Release at this location is similarly marked. Dave According to posts in the ublox forum, there are specific issues regarding timing specific features in the timing

Re: [time-nuts] Vintage Frequency Measurement

So far all the answers are about high-end expensive equipment. There were also low cost frequency meters. I have one 40 years ago that was not expensive. It wa a simple "frequency to voltage" circuit that drove an analog meter. It was made just before the digital multimeters came out, maybe

Re: [time-nuts] Vintage Frequency Measurement

In fact, I used a similar method for adjusting the AOR DDS-2A synthesizer on my Collins rig.  I tune an AM radio to WWV.  And I tun the DDS-2A / Collins to the same signal only using SSB.  Then when WWV is sending the tone modulated signal, I tune the DDS-2A calibration control to eliminate the

Re: [time-nuts] Vintage Frequency Measurement

Looks like I was able to reference your use of the three-oscillator technique and highlight the history of the technique just minutes before your email to the Time-Nuts Newsgroup. I originally referenced your successes in "Accurate Zero Beating Using the Three-Oscillator Method," QST, Hints &

Re: [time-nuts] how many seconds out does GPS discipline being to improve Rubidium stability?

Hi How an ADEV floor do you expect to see on your devices? How short a Tau are you after. Depending on the answers to those questions, splitting things can be pretty easy or pretty hard. Isolating signals between multiple test sets is a bit of a pain if the splitting is not done with active

Re: [time-nuts] Vintage Frequency Measurement

Actually the three beat method is a variation on the AGC surging method.  The latter, rather than using a pure tone, uses the background noise that comes up as the AGC makes the receiver gain increase.  What you do is listen for the slow surging and adjust to make it barely stop surging.  You

Re: [time-nuts] Vintage Frequency Measurement

On Sun, 12 Feb 2017 17:16:18 + (UTC), you wrote: >In a word,Wavemeters. Classic US onwas the BC221 with built in 100kHz crystal >calibrator A couple of years ago, I got a BC221 from an estate; had to recap the homebrew power supply the late ham had built for it, but the BC221 worked fine

Re: [time-nuts] Vintage Frequency Measurement

Hi That’s not the *accuracy* of the crystal mind you. That’s how close you do the zero beat to something else that is more accurate. The crystal is out in the open and it drifts quite a bit as the unit warms up or changes temperature due to being moved around. Bob > On Feb 12, 2017, at

Re: [time-nuts] Vintage Frequency Measurement

Hi Ok, so how does that make a BC-221 a wave meter? Bob > On Feb 12, 2017, at 7:15 PM, Wes wrote: > > On 2/12/2017 12:51 PM, Bob Camp wrote: >> Hi >> >> Maybe I’ve been wrong for the last many decades … >> >> To me a wave meter is a tuned circuit device that tells you the

Re: [time-nuts] Vintage Frequency Measurement

Hi The GR is a classical wave meter that works off of a tuned circuit and a broadband detector. The BC-221 works on an entirely different principle and has no ability at all to run in the mode that the GR operates in. Bob > On Feb 12, 2017, at 9:13 PM, Alan Hochhalter

Re: [time-nuts] Vintage Frequency Measurement

The BC-221 was mentioned in a Time-Nuts thread from December, 2015. Copying from my post in that old thread: 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.

Re: [time-nuts] Vintage Frequency Measurement

I have a General Radio Type CAG-60098-A Precision Wave Meter made for Navy Department - Bureau of Ships according to the nameplate. According to Wikipedia that would date it between 1940 (when bureau of ships was created) and 1966 (when abolished). It has an inductor in sort of a "hockey puck"

Re: [time-nuts] Vintage Frequency Measurement

Hi: When listening to a broadcast station using an analog receiver you just tune back and forth near the station frequency until you hear it, but that does not work for military radios where most of the time there is no transmission. Hence the need for frequency or wavemeters like the BC-221

Re: [time-nuts] Vintage Frequency Measurement

Hi If you look at a typical BC-221 in use, it goes from “calibrated” in a nice warm hut to the back of a jeep. It heads out to an ice cold flight line and the switch turns the batteries back on again. It bumps in and out of a batch of B-17’s setting each one up for the day’s net frequencies.

Re: [time-nuts] Vintage Frequency Measurement

On 12 February 2017 at 06:08, Scott Stobbe wrote: > I was inspired recently coming across a Lampkin 105 frequency meter, as to > how frequency measurement was done before counters. > > Certainly zero-beating a dial calibrated oscillator, would be one approach. > > Is

Re: [time-nuts] Vintage Frequency Measurement

> More recently, Alan Melia, G3NYK, reports an accuracy of 0.1 Hertz using > the same technique, http://www.alan.melia.btinternet.co.uk/freqmeas.htm . John -- Alan's web site moved from btinternet to http://g3nyk.ham-radio-op.net/ so the new URL is: "Frequency and Time Measurement"

Re: [time-nuts] Vintage Frequency Measurement

Well 5 cycles per second is more than accurate enough.  That translates to a 150 Hz error at 30 MHz, definitely negligible for the uses of all these gear.  There was no official Time Nuts group at the time, although many of us had the spirit.  Yet the capability of the BC-221 far exceeded its

Re: [time-nuts] Vintage Frequency Measurement

This reminds me. Many years ago the Titan Missile sites around here in Tucson were being decommissioned. The people at Davis Monthan AFB who maintained them were going to be out of work but had an opportunity to bump into something else on base if they got some more training. I and a