KA7OEI's blog

Random musings - usually on a technical (nerdy) subject - perhaps related to amateur radio and things found at ka7oei.com and modulatedlight.org. No AI is used to generate this content.

Monday, June 30, 2014

A 100 watt "Helical" resonator bandpass/notch filters to increase isolation of 20 meter stations during Field Day

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Follow-up: For another article with more measurement and analysis of these filters, see the 31 May, 2019 article - Revisiting the 20 mete...

1 comment:

Monday, May 26, 2014

How USB car power adapters can ruin 2 meter mobile reception!

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For an update on this article, see the posting about a "Quiet" vehicle USB power supply - LINK . For decades now, the ubiquito...

Wednesday, April 2, 2014

Making a cheap Chinese battery tester more accurate and useful

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A few months ago I was ordering some stuff on EvilBay from a vendor and noticed, for only $5 or so, what looked like a nice, little battery ...

14 comments:

Monday, March 31, 2014

Examining the Glencom VC510 UHF to L-Band Upconverter

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This is a curious little device - of which several have fallen into my hands. Often available on EvilBay for fairly cheap, these are in so...

Monday, February 17, 2014

Analysis of a repeater's antenna pattern

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Back in 1997 the antennas on the Utah Amateur Radio Club's 146.760 repeater were relocated and replaced - this, because the original, gu...

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