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
… Read more
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
… Read more
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
… Read more
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
… Read more
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
… Read more
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
… Read more
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
… Read more
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
… Read more
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
… Read more
I set my HP 5065A Rubidium standard to the 5071A. Unlike a Cesium clock, the Rubidium system does have some drift so it needs to be tweaked occasionally. I plan to come back to this post every few months to update and see if we can determine the aging rate.
… Read more