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John's Geekblog
There is no problem so big or complex that it cannot be over-engineered
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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Uncategorized

GPS Survey Antennas

by n8ur June 30, 2019
written by n8ur

I’ve recently become interested in dual frequency GPS receivers – the kind the are used for land surveying and geodetic research. More on that in another post. But along the way I’ve collected a whole bunch of antennas for these beasts, and this post is a database for my future
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June 30, 2019 0 comment
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GeneralNetworkingTest and Lab Equipment

USR-IOT Serial-to-Ethernet Converters with Linux

by n8ur June 12, 2019
written by n8ur

I’m posting this mainly because Google didn’t turn up any help when I queried about using the USR-IOT serial port to ethernet converters (also known as terminal servers) with Linux. They make several low-cost devices that are really handy if you need to talk to serial devices that are far
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June 12, 2019 3 comments
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GPSTest and Lab EquipmentTime and Frequency

GPS Frequency Stability

by n8ur April 8, 2019
written by n8ur

I couldn’t find a nice graph showing the timing performance of a single-frequency, sawtooth-corrected, pulse-per-second output from a GPS. So I measured a CNS-II GPS Clock and a surplus telecom HP Z3805A GPS Disciplined Oscillator (GPSDO) against a high-performance Cesium standard for 30 days. Here are a whole bunch of
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April 8, 2019 0 comment
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Ham RadioTest and Lab Equipment

Mini-Circuits Power Amp

by n8ur March 30, 2019
written by n8ur

Each year at the Dayton Hamvention, the folks at Mini-Circuits have a bunch of odds and ends they sell very inexpensively. Over the years I’ve gotten tons of SMA attenuators and jumper cables, and a few amplifier blocks. I’d never looked closely at one of the amp blocks until last
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March 30, 2019 0 comment
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Test and Lab EquipmentTime and Frequency

Oscillator Aging Trends

by n8ur March 25, 2019
written by n8ur

It’s well known that just about all oscillators drift, or “age”, in frequency with time. In crystal oscillators, the most drift occurs when the oscillator is young, and over time the aging rate decreases. Power-cycling the oscillator results in a new stabilization period before the aging rate stabilizes. The best
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March 25, 2019 0 comment
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Ham RadioSDR

Peak vs. Average Power in Complex Waveforms (and Gnuradio)

by n8ur March 14, 2019
written by n8ur

One of my Gnuradio projects is a tool that records IQ data covering 375 kHz — which is enough to capture an entire HF ham band (except for 80/75M). A neat trick is to retransmit such a recording to allow local receivers to tune in The Signals From The Past
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March 14, 2019 0 comment
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Test and Lab EquipmentTime and Frequency

HP 5065A Status

by n8ur February 27, 2019
written by n8ur

My faithful HP 5065A Rubidium standard, which had been converted to a “Super” model, developed an intermittent sickness and back it went to Corby Dawson for him to perform his magic.  After a realignment and fixing an intermittent connector ground, it’s back in the lab and working well, though minus
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February 27, 2019 0 comment
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Ham RadioSDR

Anan7000/HPSDR and Icom IC-7300 S-Meter Calibration

by n8ur February 6, 2019
written by n8ur

I’ve noticed that my SDR setup, an Apache Labs Anan-7000DLE transceiver used with the PowerSDR software, seems to rest the S-Meter at a quite high level when there is no signal present. This is unnerving when I try to compare my local noise floor with others who claim noise levels
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February 6, 2019 2 comments
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Test and Lab EquipmentTime and Frequency

HP 5061B-004 Cesium Standard

by n8ur November 11, 2018
written by n8ur

I was lucky enough to find an HP 5061B cesium standard with what I think is a virtually new high performance (option 004) tube. These are rare because the high performance tubes burn up their cesium supply much more quickly than the normal ones. But you get much improved stability
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November 11, 2018 0 comment
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Recent Posts

  • Hybrid PCB Assembly Technique
  • Oscillators, GPS, and GPSDOs (Part 4)
  • Oscillators, GPS, and GPSDOs (Part 3)
  • Oscillators, GPS, and GPSDOs (Part 2)
  • Oscillators, GPS, and GPSDOs (Part 1)

Recent Comments

  • n8ur on Hybrid PCB Assembly Technique
  • Steve Steoh N8GNJ on Hybrid PCB Assembly Technique
  • Roger on IC-7300 Power Overshoot?
  • 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)

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