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GPSTest and Lab EquipmentTime and Frequency

Oscillators, GPS, and GPSDOs (Part 4)

by n8ur August 26, 2022
written by n8ur

Enter the GPSDO

So far in this series, we’ve seen the strengths and weaknesses of both crystal oscillators and GPS receivers[1]I mentioned in part 1, but it’s time to reiterate — I’m using “GPS” generically. It’s perfectly possible to use the GLONASS, Galileo, or Beidou satnav systems to
… Read more

August 26, 2022 0 comment
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GPSTest and Lab EquipmentTime and Frequency

Oscillators, GPS, and GPSDOs (Part 3)

by n8ur August 24, 2022
written by n8ur

Comparing Crystal Oscillators with GPS

In part 1 and part 2 of this series, we saw that crystal oscillators and GPS receivers both have strengths and weaknesses as frequency standards.

Now, let’s compare them to understand how they differ, and how they complement each other. But first…

A slight detour:
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August 24, 2022 3 comments
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GPSTest and Lab EquipmentTime and Frequency

Oscillators, GPS, and GPSDOs (Part 2)

by n8ur August 22, 2022
written by n8ur

GPS as a Time and Frequency Standard

In part 1 of this series, I described the strengths and weaknesses of crystal oscillators. The moral of that story was that a number of processes affect a crystal’s frequency, and that you need something to calibrate and measure the XO against.
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August 22, 2022 3 comments
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GPSTest and Lab EquipmentTime and Frequency

Oscillators, GPS, and GPSDOs (Part 1)

by n8ur August 22, 2022
written by n8ur

Introduction

A lot of my recent time and frequency measurement work has been related to GPSDOs — GPS Disciplined Oscillators.[1]There are now multiple GNSS (Global Navigation Satellite System) systems so saying “GPS” is a bit US-centric. But at least for now, virtually all GNSSDOs use GPS.
… Read more

August 22, 2022 3 comments
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GPSHam RadioTest and Lab EquipmentTime and Frequency

Testing the BG7TBL GPSDO (and a couple of others)

by n8ur July 16, 2022
written by n8ur

There has recently been quite a bit of discussion on the fmt-nuts mailing list about the BG7TBL GPSDO and whether its 10 MHz output is accurate. I don’t own one but Wes Stewart, N7WS, sent me his to test.

After letting the unit warm up for 24 hours, I did
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July 16, 2022 0 comment
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GPSTAPR ProjectsTest and Lab EquipmentTime and Frequency

GPS Antenna voltage and current requirements

by n8ur July 16, 2022
written by n8ur

I am working on a current limiter circuit for a GPS antenna bias tee, and wanted to measure the minimum voltage required by particularly modern 3.3V antennas.  I did a very simple measurement of a bunch of antennas I had laying around, and these are the results.

I put a
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July 16, 2022 0 comment
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GPSTest and Lab EquipmentTime and Frequency

Allan Deviation — the Time-Nut’s Statistic

by n8ur February 4, 2022
written by n8ur

The essence of time-nuttery is measuring the stability of clocks and oscillators.  Allan Deviation (“ADEV”) is the statistic most commonly used to talk about frequency stability.  There’s a very good article about it on Wikipedia, but it’s a bit deep for many.  This post is a TL;DR description.  To
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February 4, 2022 3 comments
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GeneralHam RadioSDRTest and Lab EquipmentTime and Frequency

PowerPole Color Conventions

by n8ur October 5, 2019
written by n8ur

A lot of us use Anderson PowerPole connectors for DC power distribution. There’s a nearly universal standard to use red and black housings for 12 volt-ish (e.g., 13.8) lines, with the housings arranged per the “Orange County RACES Standard” like so:

Standard PowerPole Arrangement

Of course, to make
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October 5, 2019 0 comment
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GPS

GPS Survey — First Results

by n8ur September 16, 2019
written by n8ur

Now that I have my GPS antennas permanently mounted on my tower, I’ve done a first set of measurements to determine the precise antenna location. I collected data for 48 hours on three receivers (Trimble NetRS, Ashtech ZREF, and Ashtech microZ) and fed the results to two processing services (
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September 16, 2019 0 comment
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Ham Radio

YU7WW Antenna Switch

by n8ur September 13, 2019
written by n8ur

I’ve been looking for an antenna switching solution to use in my new ham station. I have several antennas for HF and 6M that all connect to the same amplifier in the shack, which has only a single output connector. A remote switch at the tower (about 20 feet from
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September 13, 2019 2 comments
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  • Oscillators, GPS, and GPSDOs (Part 4)
  • Oscillators, GPS, and GPSDOs (Part 3)
  • Oscillators, GPS, and GPSDOs (Part 2)
  • Oscillators, GPS, and GPSDOs (Part 1)
  • Testing the BG7TBL GPSDO (and a couple of others)

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  • Frans on USR-IOT Serial-to-Ethernet Converters with Linux
  • Oscillators, GPS, and GPSDOs (Part 4) – John's Geekblog on Oscillators, GPS, and GPSDOs (Part 3)
  • Oscillators, GPS, and GPSDOs (Part 4) – John's Geekblog on Oscillators, GPS, and GPSDOs (Part 2)
  • Oscillators, GPS, and GPSDOs (Part 1) – John's Geekblog on Oscillators, GPS, and GPSDOs (Part 1)
  • GPS Disciplined OscillatorsPart2: GPS Timing – John's Geekblog on Oscillators, GPS, and GPSDOs (Part 3)

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