Amateur Radio

QRP and FT8 with an EFHW for 20 meter band

Some time ago I made attempt to make an UNUN / EFHW (End Fed Half Wave) trafo for 14 MHz, it was a complete failure… I do not know if the cheap toroid ordered from  eBay was a fake (T106-2) but nothing worked (high SWR).

The ”not-so-good” DIY UNUN

Then I ordered the Sotabeams Pico Tuner (at a very good price). It took me about 3 hours to solder the tuner and cut, test an antenna for 14 MHz (20 meter band). The SWR was very good with the antenna at almost ground level.

The Sotabeams Pico Tuner soldered and mounted in a waterproof box

The first test with FT8 digital mode and my FT-817ND was good. The next day I mounted the antenna on the roof with one fixed end of the antenna in one of the few low trees I have at my garden. The SWR was now a little bit different (higher) but bandwidth was larger.

EFHW feedpoint/box with Pico Tuner
Antenna wire sloping down to the tree
SWR measured with EFHW mounted on roof

I noticed a large improvement in both RX and TX when putting the antenna higher up. In just one hour my TX was heard by 51 receivers on FT8 with 2.5 watts from my FT-817ND.

FT8 report from pskreporter.info (click for larger image)

Summary: I can highly recommend the Sotabeams Pico Tuner if you need a simple QRP tuner thats actually works. Also FT8 is a great digital mode for testing antennas and fast QSOs.

Amateur Radio

2nd test with DIY EFHW antenna

So I did try again with a homemade 9:1 UNUN and a 10 m wire to see if I could use it as a simple 14 MHz antenna. But no success… I actually had the best SWR high up on the HF bands.

The toroid is was a T106-2 and what I can see this is not suited for HF UNUNs…

Next I will maybe try one of the SOTA Beam antenna designs (pico-traps, EFHW tuners…).

SWR diagram with a 10 meter wire
SWR diagram with a 10 meter wire
Amateur Radio

PC headset adapter for FT-817ND

On internet there are many articles about using a PC headset for ham radio transceivers. I have been using this one from KC2RGW, Chris Esser for connecting a simple PC headset to my FT-817ND. The circuit is according to following (picture from Chris):

And here it is after some soldering:

And after some vulcanized tape:

Audio result from FT-817ND:

  • VOX on FT-817ND is working great!
  • Audio is OK, not as clear as from the original mic but OK…
  • Have some very little ”hum” but not disturbing.

So I think I’m now a little bit closer to be able to make satellite portable QSO when I can use a headset with VOX.



Amateur Radio

9:1 UNUN and longwire tests

From eBay I got a very cheap 9:1 UNUN antenna transformer for EF (End Fed) longwire antennas. To read more about the EF antennas, please google and you find a lot of info.
The unit I tested look like this inside in a small plastic box:

The connector for the coax is BNC. This is, as you can see, a very small toroid and should not be used for other then RX or QRP.
I tested the UNUN with a 450 ohm resistor between input connector and ground. This is the result (with Fox-Delta antenna analyzer):

And connected to a 16,2 meter longwire the result is:

So, with a long wire the SWR is a little bit higher but follows the same pattern as with a 450 ohm resistor. With an antenna tuner it should be possible to tune the antenna from 40 meter band up to 10 meter band.

Amateur Radio Väder- och dataloggning

Receiving NOAA with 145 MHz yagi

I had never tried receiving weather images from NOAA satellites on 137 MHz so of course I was forced to test this! I used the guides on RTL-SDR blog and SDR for Marines.

I used to very good software WXtoImg and the RX with my tracking VHF yagis for 145 MHz are perfect! Also it is possible with my Crossed Yagi for 145 MHz.

This is the WXtoImg software:

Below is a picture received with my Yagis from NOAA-18:

Below is a picture received with my Crossed Yagi from NOAA-19:

Amateur Radio

Planned portable equipment for satellite and HF QSOs

This page has moved to main page about my Ham Radio setup.

Amateur Radio

New mount of ADSB antenna

The ADSB GP is now mounted at a new side mount: