Category: Builder Projects

Backpacking with the QMX, a Pocket and a Pole

The QRP Labs QMX transceiver is a miracle of miniaturization. Sure, other rigs have achieved a similar form factor, but not with so many outstanding features built into such a tiny package. At this point I should acknowledge a very worthy exception to the rule - the Elecraft KH1. I don't own a KH1 and … Continue reading Backpacking with the QMX, a Pocket and a Pole →

The Sinatra Method for DIY Ham Radio Projects

I recently watched G0UPL Hans Summer's presentation at Hamvention 2024 on YouTube. Hans talked about 10 of his junk box projects. As you probably know, Hans is the owner of QRP Labs, a small company that makes excellent QRP radios and accessories and sells them for an unbelievably low price. I really enjoyed the presentation, … Continue reading The Sinatra Method for DIY Ham Radio Projects →

Improving a Ground Tuning Unit – using binary coded inductance and capacitance

There are 10 types of people in this world; those who understand binary notation and those who don't. Some years ago I experimented with using a Ground Tuning Unit (GTU a.k.a. Artificial Ground) to replace radials/counterpoises on my field expedient vertical antennas. A GTU is simply a series L-C tuned circuit with a current sensor … Continue reading Improving a Ground Tuning Unit – using binary coded inductance and capacitance →

Venturing Outside the Box with the End-Fed Half-Wave Antenna

So many words have been written about the popular End-Fed Half-Wave antenna that you would think it would be "settled science" by now. For several years I have been building EFHWs according to accepted wisdom, but my inquisitive mind always seeks to question why they are built that way and could they be improved? You … Continue reading Venturing Outside the Box with the End-Fed Half-Wave Antenna →

Antennas: a Riddle Wrapped in a Mystery Inside an Enigma

I owe the title of this post to Sir Winston Churchill who once used it to describe a country that is prominently in the news at the present time. It seemed an appropriate description for ham antennas too because the more I know about antennas, the more I realize how much I don't know. Maybe … Continue reading Antennas: a Riddle Wrapped in a Mystery Inside an Enigma →

Can a Manual L-match Get the Job Done?

Or can it be made just a little bit better? In part 3 of my manpack series of posts I discussed how and why I replaced a perfectly good LDG Z-11 Pro autotuner with a home-made manual L-match. To summarize, the autotuner was doing a great job but was using too much space inside the … Continue reading Can a Manual L-match Get the Job Done? →

Building a Manpack – Part 2, the QRP Rig

As in Part 1, let me define what I mean by "manpack". My manpack is a manually transportable, rapidly deployable, field expedient complete radio station for operating while pedestrian mobile or pedestrian stationary. Complete station fits into a plastic "50 caliber ammo case" The complete station - radio, battery, paddles, phones and antenna fits neatly … Continue reading Building a Manpack – Part 2, the QRP Rig →

Building a Manpack – Part 1, the Antenna

To start, let me define what I mean by "manpack". My manpack is a manually transportable, rapidly deployable, field expedient complete radio station for operating while pedestrian mobile or pedestrian stationary . The HFpack group of /PM enthusiasts are the experts in operating Pedestrian Mobile. Personally I prefer the Pedestrian Stationary style of operating. The … Continue reading Building a Manpack – Part 1, the Antenna →

A Simpler Field Expedient Rybakov Antenna for Winter

I recently received an email from Frank Barnes W4NPN who maintains an excellent website with an index of downloadable issues of the Hot Iron Newsletter. The latest issue contains a link to a PDF document from the late G3XBM that discusses a commercial Rybakov antenna manufactured in the UK (no longer available) called the X80. … Continue reading A Simpler Field Expedient Rybakov Antenna for Winter →