KA7OEI's blog

Back in 1972 an ad appeared in the Ham magazines for something that probably seemed amazing at the time: A solid state transceiver that covered the entire 2 meter amateur band (144-148 MHz - plus adjacent MARS and CAP frequencies) and did not need crystal…

Figure 1: The front panel of the Morrow CM-1 CONELRAD monitor.

Figure 1: The Heathkit HM-102 HF VSWR/Power meter.

TL;DR If you have LED headlights that are causing RF interference, ferrites alone will probably not be enough to completely solve the problem: You will probably need to put the offending switch-mode LED controller in "RF Jail" as described below.

tl:dr: Figure 1: The front panel of my "FT-280R" all-mode 2 meter transceiver including paper labels showing the "new" modes.

Note: The techniques described below should work - with only minor adaptation - for any "Longwave" time signal used by these radio-controlled (non-GPS) clocks - not only WWVB, but DCF77, MSF, BPC and both JJY signals as well. * * * * * Last year I moved a…

Figure 1: The (repaired) MFJ-998 front, now working, sitting atop my Heathkit SA-2060 manual tuner and underneath my homebrew neon bar-graph VSWR/Power meter.

Figure 1: Front view MFJ-5008 parabolic dish with integrated microphone and receiver (located on the back side).

Figure 1: The JPC-7 loaded dipole out in the wild!

Figure 1: White board from Quartzfest!

Figure 1: Power/VSWR meter using ИН-13 neon bar-graph indicators.

Figure 1: The ALS-500M front panel.

Why the filter?

From how far away can you hear the spurious emissions from a known-noisy PV system?

"And now, for something completely different!"

Note: While this article describes a modification of the Pico Keyer to reduce RF susceptibility, it also talks about general methods to minimize/reduce RFI-related issues for both portable and "base" stations: This specific topic is covered near the end of

QRM from a transmitter to receivers on lower bands [Go to the end of this article for an "After-Field-Day follow-up" about this filter] A friend of mine belongs to a club in a town north of me and he was describing an issue that they've been having for the

Two transmitters, one antenna There are occasions when it is desirable to combine two transmitters - and receivers - onto a single antenna - perhaps at a busy repeater site where more than one link or repeater is required.

The Astro 200 The CIR Industries Astro 200 is a compact, synthesized 100 watt HF transceiver from the mid-late 1970s that covers the 80, 40, 20, 15 and 10 meter bands.

"Does a lit-up Nixie tube in a forest wear out even if there's no-one to see it?"

Figure 1: The SAA-2N, a variant of the Version 2.

Figure 1: Front panel of the SDR TX/RX antenna switch showing the the 3.5mm audio connectors and the red/green RX/TX LED - which have been swapped to be in their proper location.

The problem Figure 1: A "Beelink" small form-factor PC.

Figure 1: The Renogy RNG-DCC1212-20 - an isolated and current-limited battery charger, intended for use with vehicle electrical systems.

Figure 1: The RX-888 Mk2.

Figure 1: The TS-590G into which the ProgRock was installed.