Category: Miscellaneous topics

An alternative mini-GTU design by Tim KQ4TQ

As I mentioned in the last post on Ham Radio Outside the Box, I received a surprise package in the mail from Tim KQ4TQ in Georgia. Tim sent me his build of a mini Ground Tuning Unit (GTU) that is simpler in design than the one I built. Tim's design is a single inductor of … Continue reading An alternative mini-GTU design by Tim KQ4TQ →

The magic carpet ground plane is grounded, but the GTU keeps flying.

Ham Radio Outside the Box receives quite a lot of email every week from readers with questions, comments and suggestions. One such email came about as a result of an article in the outstanding newsletter from the Surrey Amateur Radio Club called the Communicator. The editor of the Communicator is Canadian Amateur Radio Hall of … Continue reading The magic carpet ground plane is grounded, but the GTU keeps flying. →

Shacks On The Air anyone?

There has been an explosion of "On The Air" programs lately. I think SOTA (Summits On The Air) may have kick started the trend. To my mind SOTA remains the purest and best of them all. Although there are many drive-up summits, many others require strenuous effort to reach the "activation zone" on foot. Unfortunately, … Continue reading Shacks On The Air anyone? →

A Mini Ground Tuning Unit and a magic carpet for portable ops

In the last couple of posts I discussed my quest for a simple portable antenna that could be rapidly deployed in a very limited space, for example in a small clearing while hiking through the woods. Such an antenna would have to be a short, yet efficient, vertical that occupies a very small footprint on … Continue reading A Mini Ground Tuning Unit and a magic carpet for portable ops →

A Linear-Loaded Monopole antenna for hiking

There is a lot of information online about Linear-Loaded Dipoles, but I haven't found anything at all about cutting a Linear-Loaded Dipole in half to create a Linear-Loaded Monopole worked against ground. The legendary L.B. Cebik (W4RNL, SK) published a design philosophy for an 80m Linear-Loaded Monopole, but it didn't match what I had in … Continue reading A Linear-Loaded Monopole antenna for hiking →

A short and maybe not-so-sweet HF antenna

A lot of information has been posted online recently about very short portable vertical antennas. There must be some magic in how they work, surely, since they appear to disobey the laws of physics. I used to own one called a "Miracle Antenna"; it was manufactured in Quebec, Canada. It comprised a 57-inch telescoping whip … Continue reading A short and maybe not-so-sweet HF antenna →

The CFHW – a simple, efficient HF antenna I may never use

What in Heaven's name is a "CFHW"? A CFHW is a Center-Fed Half-Wave antenna. You may know it better as a dipole and it is indeed a highly efficient simple wire antenna. I can't claim originality for the term "CFHW"; it started as a joke on one of the forums I follow. Following the trend … Continue reading The CFHW – a simple, efficient HF antenna I may never use →

A highly efficient multiband QRP L-match builder project

Here is a project that provides a much more efficient way of matching an End-Fed Half Wave antenna than the usual 49:1 impedance transformer. High ratio transformers are prone to inductance leakage, core saturation and overheating leading to low efficiency. Although a 49:1 (or similar high ratio) transformer can present a low SWR to a … Continue reading A highly efficient multiband QRP L-match builder project →