FTS-4100 Cesium Standard tests

It wasn’t too hard for the guys to convince me to take a Cesium frequency standard to my portable location in Michigan to drive the HPSDR receiver that will do band recordings for the HamSci 2017 Total Solar Eclipse HF Wideband Recording Experiment. I had been planning to use a GPSDO, but that would be too simple. My “sort of” portable Cesium is an old FTS-4100 that came out of military service. It was designed for shipboard use (I think […]

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Hermes SDR as spectrum analyzer

I was fussing about signal generator output accuracy because I wanted to calibrate my HPSDR Hermes software defined radio (“SDR”) so that I could calculate the absolute power input in dBm, assuming a 50 ohm load impedance) based on the dBFS (db full scale of the ADC chip) output from the radio. This is in preparation for the upcoming solar eclipse, where as part of the HamSci 2017 Total Solar Eclipse HF Wideband Recording Experiment I’m planning to use the […]

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Update on Boring Signal Generator Stuff

Just when you thought it couldn’t get more boring (reference my last post about signal generator calibration… I did all these careful calibrations of my signal generator to check its accuracy and linearity. Everything looked good, except that the signal reading was about 1 dB low. HP power meters have a calibrator providing a 50 MHz signal at 0 dBm that is (supposedly) very precise. I have a total of four meters with those calibrators, and I decided to cross […]

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Boring Signal Generator Accuracy/Linearity Data

I want to calibrate my software defined radio receiver prior to doing a bunch of recordings of the ham bands for the upcoming solar eclipse (check out the HamSci web page for details). I have an HP 8642A signal generator which has high-precision attenuators and should be a very good reference to measure recorded amplitude vs. actual. Unfortunately, this generator is a decade or two out of calibration, so I thought I’d try to check its performance (amplitude accuracy, and […]

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