You can think you have all connectors that you will ever need "in stock".

I have around 150 different kind of connectors or adapors at my house but the one that you need………,I  needed a F connector to BNC adapter so I could use my minivna for measuring the delay lines, yes I could make a small adapter cable but to make the delay lines you need to be as accurate as possible.

10/06/2020

How to…..

I had no idea what the velocity factor of the coax is and I could not find the datasheet online. If you have the same problem, this was my solution.

I had 9 pieces of coax around 25meters long so to determine the velocity factor some simple mathematic are used and a minivna.

300 (speed of light) divided by 25m (length of the coax) is 12Mhz

12Mhz / 4 (1/4 wave or 90°) is 3Mhz

If you use commonly used Vf it will be 0.66, 0.85 or 0.88.

3Mhz multiply by 0.66 gives you 1.98Mhz.

3Mhz multiply by 0.85 gives you 2.55Mhz.

3Mhz multiply by 0.88 gives you 2.64Mhz.

If you connect the coax on to the analyzer and  you leave the other end of the coax open you will see the

lowest Z and X to a certain freq.

You see on the image above that the Vf for my coax will be 0.85Vf.

300/25 = 12Mhz

12Mhz/4 = 3Mhz

3Mhz x 0.85 = 2,55Mhz

As you can see I am very close of the measuring of the analyzer.

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Second option

There is a second way to do the measuring with an analyzer.

Use a T connecter and on the first end connect the coax and on the other end connect a dummy load

the third end will go to the analyzer.

The X on the analyzer will be more visible.

On the YCCC manual they say that you have to make a 40° and a 20° delay line.

Calculation is not that hard and is described in the manual but I know from experience it’s can look complicated.

With a minivna you will not see 0 at Z but very close to 0 the same for the X.

In my situation with the measured Vf of the coax!

300 / 1.83 = 163,93 meters

163,93 / 4 = 40,98 meters

40,98 x (40/90) = 18,21 meters

18,21 x 0.85 = 15,481 meters

So the coax would be 15,481 meters long.

The delay line will be 90° and lowest Z and X at ….

300 / 15,481 = 19,378Mhz

19.378Mhz / 4 = 4,844Mhz

4,844Mhz x 0.85 = 4.1179Mhz

40° delay line

Especially for this site I did both options explained above so you can see the difference on the analyzer.

For the 20° it’s the same calculation

300 / 1,83 = 163,93 meters

163,93 / 4 = 40,98 meters

40,98 x (20/90) = 9,10 meters

9,10 x 0,85 = 7,740 meters long

The delay line will be 90° and lowest Z and X at ….

300 / 7,740 = 38,759Mhz

38,759 / 4 = 9,689Mhz

9,689 x 0.85 =  8,236 Mhz

20° delay line

Especially for this site I did both options explained above so you can see the difference on the analyzer.

After the measuring and putting on the connector on the other end of the coax I always check again with the analyzer.

After the check and all is ok I made them waterproof with vulcanizing tape.

Coax from antennas to phase unit

On the manual of YCCC they tell you to have 9 pieces (9 antennas) of coax that connect the antennas to the phase box.

All of them has to be the same length, Depending what type of analyzer you use but mine can calculate the length of the coax.

To check all is ok I will also control it manually.

So I will unroll the 9 pieces and strap them together.

The length of that coax is not that imported just make sure you will reach the middle of the circle and be sure that they are all the same length.

Mine are 24,75 meters long. In the manual of YCCC they say around 70 feet (21,34m).

The raison why mine are longer is so I can test in the field different distances and

I cut the coax at the length of the shortest one I had.  

Some final words of accuracy.

Will it be much of a difference if one coax is a few centimeters longer than another, I don’t think so.

Even for the delay lines as you can see on the analyzer you have quite some bandwidth where Z or X are almost zero.

But remember, and the manual of YCCC talks many times about it to be as accurate as possible.

A few centimeters here and there could be at the end all together a non-good functional antenna.

So the coaxial lines are made except for the chokes.

More info on that part in a different subpage.

07/11/2020