MarME

Category: Uncategorized

  • Restoring an HP 8591E Spectrum Analyzer

    Background When I bought my HP 8591E spectrum analyzer it came with a warning:It works — but only if you leave Option 130 (the narrow-bandwidth IF) disconnected. Oh and it has a strange glitch in the amplitude – as the previous owner told me.The Option 130 board was in a separate shielded bag because the…

  • GPSDO

    An overview of the GPSDO project Building a GPS-Disciplined Oscillator (GPSDO) Background and inspiration A GPS-Disciplined Oscillator combines a local high-stability oscillator (typically an OCXO) with the long-term accuracy of GPS time.Over the years, many excellent DIY versions have appeared; the two I learned the most from were: My build followed Lars’ architecture most closely.…

  • Low resistance metrology

    How a Marktplaats find sparks doubt about accuracy. Background I recently found two vintage Bleeker precision resistors on Marktplaats: a 0.1 Ω ±0.01% and a 0.01 Ω ±0.01% model. After some hesitation I bought them: to me, Bleeker is a long-gone pinnacle of Dutch engineering. A tolerance of ±0.01% is the same as ±100 ppm.…