KA7OEI's blog

Exploring the Ameco PCL-P Nuvistor cascode preamp/preselector

Reducing RF susceptibility for the HamGadgets "Ultra Pico Keyer" - and mimizing RF issues on portable HF stations in general

A 15 (and 10) meter high-pass filter for Field Day

The construction of a hybrid ring combiner: Using the same duplexer, feedline and antenna for two repeaters/links/transmitters

Refurbishing a CIR Astro 200 HF amateur band transceiver

Using a PIR to reduce wear and tear on a Nixie clock

Repairing a NanoVNA "V2" with nonsensical readings ("Blown up" input)

Ali Express "SDR TX/RX Switch" - A design NOT well thought out...

A short-term capacitor-based "UPS" for mini (NUC-type) PCs

Charging LiFePO4 batteries from a vehicular electrical system - the problems and a solution.

Frequency response of the RX-888 SDR at the high and low ends (Above 30 MHz, below 1.5 MHz)

The "Universal TCXO" - better stability for the TS-590 (and other radios) using the QRP Labs ProgRock 2

Hiking and POTA (Parks On the Air) operation from Arches National Park (US-0004)

Neon bar-graph VSWR/Power meter using the ИН-13 (a.k.a "IN-13") "Nixie" - Part 2

Neon bar-graph VSWR/Power meter using the ИН-13 (a.k.a "IN-13") "Nixie" - Part 1

Rewinding the stainless steel coils with silver-plated copper wire on the JPC-7 and JPC-12 antennas

Reducing QRM (interference) from a Renogy 200 watt (or any other!) portable solar panel system

Observations, analysis and modifications of the JPC-12 vertical antenna

Repairing a dead RX-888 (no A/D converter clocking)

Analysis of interference from a SolarEdge PV (solar) electric system.

Using an external clock with the RX-888 (Mk2)

Repairing a dead Kenwood TS-850S

Reducing RFI (Radio Frequency Interference) for a POE (Power Over Ethernet) camera or wireless access point

Remote (POTA) operation from the Conger Mountain BLM Wilderness Area (K-6085)

"TDOA" direction finder systems - Part 2 - Determining signal bearing from switching antennas in software.