3D Printing Hacks HF Portable

The GAWANT Antenna

After my QRP/Portable QSO with a Japanese station, I was contacted by Hiroshi JL1KLK who asked if he could mention my post in his blog. I obviously consented. In his post Hiroshi shows the similarities between his QRP operations and mine: we both have glasses, we both wear caps, we both are middle aged, we both operate near the water, we both operated standing. There was, however, a difference that stood out: I use an MLA, while he uses a vertical antenna called GAWANT.

Since I always desired a portable vertical I decided to look into it and eventually build my own. But what is the GAWANT? After some research, I found that it is design somewhat popular in Japan.
Technically, it is an half-wave vertical end-fed in a FT817-friendly package. After asking, Hiroshi very kindly provided me all the details with this wonderful document:

Click for more info

In it, I discovered that the original designer, Ariga JF1QHZ, named it after his native Shinagawa-shuku neighborhood.
I already had everything I needed to build it, except of course for the 2 meter long telescopic rod and the case. The former was acquired at for $8.50 and the latter was designed and 3D printed by myself. You can check it out at Thingiverse, if you wish.

The GAWANT is ofter used directly on the front BNC of the FT817. I find this impractical because the rod will come uncomfortably close to the operator’s head, and also because the leverage force expressed on the connector appears to be too much. I prefer attaching it to the rear SO239 connector, by means of a right-angle PL259 to BNC connector. I am not excluding the idea of redesigning the case in order to address this particular usability aspect.

The first test of the antenna was in my backyard (these days it might be better to stay home…) and the results were encouraging: in just a few minutes during the WPX CW contest I made 3 contacts: Texas, Europe and Africa. Not too bad!

Here are some more pictures:

Will I switch from using Magnetic Loops to Vertical end feds during my operable operations? Probably not, still the GAWANT is a very nice – super portable – HF antenna that I now have available. Given the cost of making it (I estimate less than $20) I think everyone should build one!

Many thanks to Hiroshi-san for providing all the information, and to Ariga-san for the design!

HF Portable

Portable QSO with Japan!

Last Sunday I took my Portable setup to the river, as I often do. Propagation was a bit short with Europe totally closed when suddenly – to my disbelief – JH4UYB popped up at S8.
It head Japan twice before with the Loop, but never as strong as that.

After beaming about 330 degrees (the same direction I normally use to work W7) I immediately started calling. Incredibly, part of my callsign was picked up right away! The rest of the QSO, however, took more than 3 minutes to complete thanks to the perseverance and the professionalism of Masaki, the Japanese operator.

HF Portable

QSO from the Pier

Once again in Italy, once again at the beach. The weather was a bit cold but propagation warmed me up good.
Heard a lot of US stations but couldn’t make the pile-up. On the other hand, I had the pleasure of a QSO with OH73ELK.


K1FM-3 Launch

During my 2019 xmas holiday I took the occasion to launch again in Italy. Unfortunately I made the mistake of loading too much gas and, as a result, one of the two lift balloons popped shortly after take off.

The silver lining of this short-lived launch is that I think I found my definitive construction style.
The think food foam sheet I used is useful to provide some mechanical resistance to the solar cells and also to keep the transmitting electronics a bit warmer.

I have a feeling that next launch is going to be much, much longer!


K1FM Pico Balloon Launch !

After months of research and preparations, it finally happened: last Sunday September 22nd, together with my wife and with Joe N2DI we launched my first pico balloon.

The unit currently transmitting uses Joe’s callsign N2DI. We actually launched another one with mine own callsign but unfortunately its antenna got twisted and, because of that, it could only be heard at a very short distance. Here are some pictures, and here are all the position reports we received so far:

The balloon last flew over Miami where it sent a CW message that was recorded using a remote SDR receiver.

More details to follow!