Yagi on the Test Stand

[W9WD]

I got the hardware I was waiting for and so I started assembling the Yagi for testing

Here's most of the hardware I was waiting for. I made the sandwich plates.




The boom without elements. 2.5" square 1/8 wall aluminum



One by one I put in the 5/8" elements. Had to stop and cut some tree limbs out of the way



The last thing to go on is the feed/gamma attach point



I have to make up the cable I bought and attach the gamma match before I can test. I'm also studying for my General ticket so my time is getting stretched a little thin
This antenna will be tuned to the middle of the 10 meter band.

 

[HomerBB]

Nice!

 

[W9WD]

Just for grins I hooked up an old 40 ch CB and played with it. ( I still haven't got my new coax put together to test on 10m).
I was able to get 1.05:1 (needle barely moved) on CH-40 and 1.4:1 on CH-1.

The Gamma match was set like this.



Brass rod fully inserted.
You can just barely see the marks I made on the element as I moved the ground strap in.
I wonder if cutting off the excess brass rod would make a difference?

 

[Highlander_821]

Sick! (in a good way)

 

[W9WD]

I got my coax hooked up and tried it around 28.4 --- 28.5
Looks like 1.1:1 to 1.2:1
I think I smell a rat.
It will be interesting to get this thing up off the ground and see what happens.

 

[Marconi]

I got my coax hooked up and tried it around 28.4 --- 28.5
Looks like 1.1:1 to 1.2:1
I think I smell a rat.
It will be interesting to get this thing up off the ground and see what happens.

You might be right about the rat. Being that close to the ground will detune and make the SWR appear better, but that is a very good start. I tune my beams at installed height and that eliminates changes when raising the antenna. If you can't do that, then you have to anticipate in your planning and use trial and error.

Very good looking construction and ideas. You asked about cutting the extra end of the gamma rod beyond the dog bone connector. I can't say for sure, but there are opinions from folks that should know, saying that is a good idea and helps in a big way to reduces asymmetry problems using the gamma.

Good luck and keep us posted.

 

[Slam Dunk]

Get a wooden ladder and prop the beam up on it vertically with the reflector end on the ground and then check the match. I would make note of where the match falls at it's lowest point.

With the Gamma match set at half way (assumming that you you are feeding the antenna with even wave lenghts of Belden 9913) adjust the length of your driven element until your match fall in at the frequency that you want.

I would not expect an antenna that is resonant at 26.965 to also have an ideal SWR over a 1 Mhz range, I would question that reading.

After you have your match set, leave them with the reflector on the ground and wait for rain (Superstition?) after it has rained on the beam, check your match. If the match is still low then it is ready to go up in the air.

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