Hello everyone
I am reporting back after some bad WX days and waiting for the moment to strike.
Here's a link to the PDF of the antenna, for a refresher course.
http://www.qsl.net/4/4x6on/RADIO%20MANUALS/HY-%20GAIN/HY-GAIN--AV-18HTJR-5BD-VERT%20ANT.pdfI thought of a little re-cap about the arcing insulator used in the HyGain 18HTJr.
The 1960's looking vertical, small brother to the HyGain HyTower. It was a very nice thread and in the end I gave up finding the right material to stop the arcing inside the insulator for 80M.
Mark, KA2QFX, was nice to run some of the math and modeling trying to figure out how the antenna was working. I took a shot from my road of hard knocks that there was a capacitor of sorts from the top portion of the mast being inserted into the lower mast, through this insulator. Mark calculated around 25PF. There are cage wires used for loading to move your desired operating frequency, by placing a jumper at the appropriate spreader arm.
So, my thought was to beat this thing with a vacuum variable mounted on top. pics attached.
A nice Ruskie job for a total of $100. 5-100pf @ 25KV. Should handle 75A of RF current.
Applied a slowly increasing RF power from my trusty Ameritron AL1500 and went to max that the amp could put out. Waaaaaaaaay past 1500 WATTS OUT.
SWR never moved and it sat there for many minutes making evil RF into the aether.
Success!!!
Thanks for the many many thoughts and ideas and the hard work of Frank (The Slab) for making the Delrin pieces. And Mark for his effort and calculations.
Here is a link to the original thread and my woes.
http://amfone.net/Amforum/index.php?topic=30119.0I would like ideas to protect the connections and the mechanical adjustment part of the cap.
My gut says fill in the porcelain cup and top of the Delrin with that clear sealer??? RTV???
The electrical contacts on the vac cap and contact to the mast need some treatment that will address the different metals and Ma Nature.
The additional 1 lb or so doesn't seem to bother the integrity of the antenna. The cage wires keep everything in alignment...........for now.
Geday
Fred
