I agree this is very interesting. It reminds me of Mosley’s descripton of loaded elevated radials. The antenna seems to be comparable to a Mag Loop but the losses are different. It would be good to model and see, but elevated radials typically really help with ground reduction. Thank you for sharing
Seems that the take off angle may change by moving the ham sticks. Sounds like a very clever design that could be put up or taken down in a few minutes. The best HOA beater I’ve seen is a flag pole in the back yard. Everyone said the flag pole is ok but why the back yard? He had a foot long piece of plexiglass with a ham stick bracket and 2 one inch pieces of 3 inch plastic pipe for guide rings. At night the flag came down and up went the ham sticks. In the morning he swapped them. The flowers at the bottom hid the coiled up coax and bracket. He just unscrewed the sticks.
Hi Dave. What about atas120 antenna ? Will that work as is placing it on my roof ? With no additional radials (insulated wires or metal ones) . Will It be still a compromise on the bandwidth section rather on the performance ? I think of placing it on mast of 5 meters high . And of course having it fully grounded. 73s from SY1DAL, Jimmy
Hey Dave, what are your thoughts regarding installing a screwdriver antenna for long term use. My QTH backs up to the Cape Fear River. I installed a Wolf River Coil vertical and am really impressed with its performance. I’m just not thrilled about running outside to change the tap when I change bands.
If you didn't have the ability to really tune, and just rely on the math you've done for the length of your driven element and the length of your radials, would 45 degrees work better to put you close to 50 ohms? I'm making two separate 1/4 wave ground plane antennas, but no tuning and my measurements are rather exact, but I did my math based on 45 degree angle radials. Is this making sense? Because I'm not tuning at all, I don't want to rework my math because I did it based on 45 degrees.
I like watching your channel. Unfortunately every talk I hear you you give about an antenna, it's always "high Q." Of course it's always the antennas that would work in my space. Isn't every antenna compromised? Of course, the bandwidth is narrow, but if every time you tune to a new frequency you used the autotuner to keep it as close to 1:1 as possible, wouldn't that be ok? I'm new, so I'm just trying to understand this.
This is not a new idea. Scorpion Antenna recommended and sold this configuration years ago with their big Screwdriver antenna for portable operation, they may still offer it. It can be supported nicely with a speaker tripod, these are sturdy and reasonably priced. The coil rises and falls into the lower tube with screwdriver antennas. There is no moving tap, a threaded rod moves the coil and the whip is attached to the top of the coil. The high Q of these coils lowers the drive impedance considerably, they are lower than 30 ohms on the lower bands. As less coil is used the impedance rises. 73 de w6akb
I beg to disagree. Performance is degraded. The big inductor is at the highest current point and will be lossy. Also, the radiator is short so not very efficient.
I agree this is very interesting. It reminds me of Mosley’s descripton of loaded elevated radials. The antenna seems to be comparable to a Mag Loop but the losses are different. It would be good to model and see, but elevated radials typically really help with ground reduction. Thank you for sharing
Seems that the take off angle may change by moving the ham sticks.
Sounds like a very clever design that could be put up or taken down in a few minutes.
The best HOA beater I’ve seen is a flag pole in the back yard. Everyone said the flag pole is ok but why the back yard?
He had a foot long piece of plexiglass with a ham stick bracket and 2 one inch pieces of 3 inch plastic pipe for guide rings. At night the flag came down and up went the ham sticks. In the morning he swapped them. The flowers at the bottom hid the coiled up coax and bracket. He just unscrewed the sticks.
This was an interesting video for sure. Thanks Dave!
Hi Dave. What about atas120 antenna ? Will that work as is placing it on my roof ? With no additional radials (insulated wires or metal ones) . Will It be still a compromise on the bandwidth section rather on the performance ? I think of placing it on mast of 5 meters high . And of course having it fully grounded. 73s from SY1DAL, Jimmy
i'm actually doing the same thing with my tarheel... except i just have a bunch of wire radials out from the post that the tarheel is attached to
Magnetic Loops are Perfect for this Purpose,
Hey Dave, what are your thoughts regarding installing a screwdriver antenna for long term use. My QTH backs up to the Cape Fear River. I installed a Wolf River Coil vertical and am really impressed with its performance. I’m just not thrilled about running outside to change the tap when I change bands.
Scorpion Antennas has made these for years.
MFJ sells a screwdriver vertical antenna.
Thanks, Dave. 73, AC3HT
If you didn't have the ability to really tune, and just rely on the math you've done for the length of your driven element and the length of your radials, would 45 degrees work better to put you close to 50 ohms? I'm making two separate 1/4 wave ground plane antennas, but no tuning and my measurements are rather exact, but I did my math based on 45 degree angle radials. Is this making sense? Because I'm not tuning at all, I don't want to rework my math because I did it based on 45 degrees.
I like watching your channel. Unfortunately every talk I hear you you give about an antenna, it's always "high Q." Of course it's always the antennas that would work in my space. Isn't every antenna compromised? Of course, the bandwidth is narrow, but if every time you tune to a new frequency you used the autotuner to keep it as close to 1:1 as possible, wouldn't that be ok? I'm new, so I'm just trying to understand this.
This is not a new idea. Scorpion Antenna recommended and sold this configuration years ago with their big Screwdriver antenna for portable operation, they may still offer it. It can be supported nicely with a speaker tripod, these are sturdy and reasonably priced. The coil rises and falls into the lower tube with screwdriver antennas. There is no moving tap, a threaded rod moves the coil and the whip is attached to the top of the coil. The high Q of these coils lowers the drive impedance considerably, they are lower than 30 ohms on the lower bands. As less coil is used the impedance rises. 73 de w6akb
this is pretty much what I do with my tarheel.. speaker stand, alu bracket and then a bunch of wire from the bracket
Nice
It sounds like a candidate for further testing.
thanks Dave 73 AK4VO
Hope you're doing well. Looks like the Bon Ton is going to find a new home near you. May have to pay a visit there.
73. KF0IYN
I beg to disagree. Performance is degraded. The big inductor is at the highest current point and will be lossy. Also, the radiator is short so not very efficient.