30/09/2020

I will try to make it as simple as possible and I know there are many ways discussed.

After having some problems myself, I once asked the question on a forum.

Let me be clear everyone had their opinion which I have the utmost respect for.

The 40m 4sq has been here for several years now and as you may have read I can say that I have a little experience.

My suspicion has also been confirmed by ON8DM who is an expert "in my eyes" in this field.

How do we start to fine-tune now.

We're going to lay down all verticals except 1.

Then those that lay down break all connections.

You have to adjust the verticals to "lowest X" 100Khz below the frequency of your preference.

As an example, I am more of an amateur who likes to do phone so my preferred frequency is 7.150Mhz.

My antennas must therefore have lowest X at 7.050Mhz.

As you can see, there is 1 that has a reasonable deviation and that is the NE measured at the foot.
As soon as it does not rain, I will adjust it and repost an image.(adjusted)

The sw measurement also has a small deviation, but not worth adjusting!

When everything is set up I will take a measurement on dumped power and post it here as well.
This would normally be very minimal.

Why 100 kHz below your preferred frequency?

Because through mutual coupling of the antennas, the frequency will be about 100 Khz

higher than the one that you initially adjusted on your antenna.

When the first has finished tuning to lowest X, lay down that vertically and break the connections.

Then you start with vertical nr 2. When this is done go nr 3 and 4.

If all four are tuned this way, this should be the best tuning you can get with a 4sq.

You might have to tune it up a bit, but that will be very minimal.

If you think that all 4 antennas will ever be perfectly equal then

I have to disappoint you because there are very few who achieve that.

Not that it's impossible, just assume it won't be.

it's not roket sience;
These are the power per antenna measured at the base with a daiwa CN410.

Inputpower was arround 100W
Here and there there is slightly more or less power per antenna, so the total power will be slightly higher.

Every vertical should measure the same power (25W). The only difference is that the phase of the fields at every vertical can vary. Using a phase difference will create a constructive interference towards the NW and a destructive interference towards the SE, for example. This creates the F/B ratio and makes the antenna directional. A different phase does not influence the power at the antenna.