larsthunberg.se

Built one in May 2020. See this article on AMSAT-SM web.

Some pictures of the new installation of the Vårgårda Yagis in september 2019.

2 x 6 el VHF yagis with switchable circular polarization. Mounted in 45 degree angle.

2 x 13 el UHF yagis. One vertical and one horizontal. Switchable.

I have a simple 13.5V PSU from Velleman, works OK and seems it has low RF noise. But it only has one connection terminal, 4 mm banana plugs. I started looking for a terminal connection board but the prices was very high.

So I did a very simple mod, I just drilled two holes in the front panel and mounted two extra 4mm banana plus and connected internal to the same connections points.

This year, 2019, I have been a ham radio operator for 30 years!

After some ”not so good attempts” making a EFHW trafo I made a new one with a real FT240-43 Amidon Toroid. I followed this guide:

Construction transformer: https://vk3il.net/projects-antenna/efhw-matching-unit/

This is the transformer in a waterproof box:

The measurements with a 5 kohm resistor (yes I know it’s a little to high impedance) gave the following result with my antenna analyzer:

And after adding a Sotabeams wire (https://www.sotabeams.co.uk/antenna-wire-lightweight-100m/ ) and cutting it to resonate on 7 MHz (40 meter) I got the measurement below. The wire was very low over ground, just 2 meter. I did not measure the exact length of the wire.

It is very good on 40 m but I can not get the SWR under 3.0:1 at 20 m and 15 m. This is no problem as I will run this antenna with a remote tuner from LDG. It seems that I can use this antenna on 80 m also…

What I understand is that some commercial antennas use some kind of loading coil to make it resonate on higher bands.

Below is the measurement with the wire mounted from the roof to a tree in the garden. As you can see it is much better at higher level above ground and even possible to use at 80m! It can be used without tuner on 40m (SWR 1.5:1). Resonance for 20m and 15m is to high

When using a LDG remote tuner RT-100 it is no problem using all HF bands. Below are some pictures after mounting. I will probably make a better setup later at some other place on the roof of the house.

Updated 2019-12-31

New mounting at roof for trafo and tuner: