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That is not bad at all. You can trim your capacitance hat a 1/4 inch on each of the rods, this will shift the swr bandwidth up higher a little. I put a cap hat on mine and that is how I tuned it real nice.

Looks great Does it stay at 1.0 swr all the way to 27 600 I would like to know your down tube measurement, from the bottom of the mounting bracket to the bottom of the hoop. What is the diameter of your lower hoop. Thanks

Nice J pole you have there

If you need any other measurements off my antenna, I will gladly provide them for you

When I removed the four spoke Hat I substituted a 35 1/2 inch pieces straight tubing to bring it back into resonance. So the total height of the top section from The top of the bracket to the tip is 82.75 inches.

Then the resonant frequency would shift higher somewhat. Maybe around 100 to 200khz.

Did you ever model the AP with the straight top section like mine has.

It sounds good may have to try one. I use the 636L on SSB and a M6B on Am with my 148

When I built a 40m monoband vertical with top loading. I used 6 spokes 3 foot long each, out of 3/8 tubing. The antenna ended up being 25 foot tall, and the feed point impedance did drop down. Not enough to use a shunt coil at the feed point, but it did drop down some.

The more you have the shorter they can be to have the same capacitance. You can also use a perimeter wire to build more capacitance. The diameter of the conductor does make a difference.

Nice model That is what I kind of figured what would happen going higher with it. I also like the antenna better with the straight top section I have on, then with the capacitance hat like the original design. It just seems to play better.

Very interesting. I have a plasma in the living room. I can hear it on 40 meters throwing hash all over the band, but not on 10 or 11 meters with the AP.

Thanks for the input. I do like the performance better at 20 foot mast height, since I do not local talk that much. I was going to put it on a 30 foot mast, but I do not know how it will affect performance. Maybe this antenna is more ground dependent than I thought. Also the wider lobe will be...

Thanks Troubleshooter

I removed the ground strap across the base insulator on my 25 foot mast holding the AP up. My swr curve shifted up 300khz from the original 26.965 to 27.600 to 27.280 to 28.000. I did notice more local power line noise compared to the mast grounded. The transmitter seems to be operating fine...

Thanks Riverman71 I just try to share my findings with antennas to whoever needs some help. What I did notice about the AP is that with my shorter support mast, it seems to work better for DX contacts. This just could be differences in propagation, or who really knows. Example.. My mast is...

I tested it with an analyzer, then backed it up with my Yaesu ys-60 watt meter. Also the SWR meter on my 1000MP agrees with the results.

I like the antenna very much since I built it. It's compact size and light weight make it a good choice.

When I first built it according to the factory manual with the capacitance hat, It works very well with about 300khz of bandwidth between the 1.5 to 1 points. I wanted to get it a little wider than that, so I removed the cap hat and put on a straight tubing section. The bandwidth now covers...

Will do later tonight when I have more time.