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eHam Forums => Mobile Ham => Topic started by: KE5KDT on April 02, 2014, 07:29:10 PM



Title: Push up pole mounted screwdriver with hamsticks as the ground???
Post by: KE5KDT on April 02, 2014, 07:29:10 PM
I purchased an Alpine 100SP screwdriver to install on a 30 foot push up pole (not for mobile use in this configuration) and want to put an array of about 8 hamsticks in the 40-10 meters freqs in a circle around the bottom and connect the shield side of the coax to them as the ground plane.   The question is whether that would be sufficient as a ground plane to have an effective antenna?   I have several other antennas, hexbeam, dipoles, vertical, etc., so this is just an experiment.   Criticism of all types accepted.  Bob


Title: RE: Push up pole mounted screwdriver with hamsticks as the ground???
Post by: KG4RUL on April 02, 2014, 08:29:57 PM
The 30 foot push-up pole may not be needed and presents a stability problem without a lot of guying.

Here is one commercially available solution:
http://www.scorpionantennas.com/Home-Antennas_c_19.html (http://www.scorpionantennas.com/Home-Antennas_c_19.html)

Note that the antenna is very close to ground level.  Your main concern, if you cannot control access, is to prevent anyone from touching the elements while transmitting.


Title: RE: Push up pole mounted screwdriver with hamsticks as the ground???
Post by: AA4PB on April 03, 2014, 05:45:24 AM
Hamsticks are pretty lossy, especially on the lower bands. I don't think they will make a very effective counterpoise for your vertical.


Title: RE: Push up pole mounted screwdriver with hamsticks as the ground???
Post by: KE5KDT on April 03, 2014, 06:07:08 AM
Thanks for the reply's gentlemen.  I looked at the Scorpion site after the link was posted and that is exactly what I had in mind.   Sometime you have an idea (like this) but when you do internet research it is hard to put into words exactly what you are looking for which is why I turned to eham.
I've tried a tripod mounted screwdriver with a top hat made from guitar strings and used tape measure radials and it worked pretty good although understandably not efficient.    I did get solid contacts of about 1000 miles with that setup on 17 meters.  Possibly someone that has tried the Scorpion set up will see my question and give a report.   Thanks again.  Bob


Title: RE: Push up pole mounted screwdriver with hamsticks as the ground???
Post by: K0BG on April 03, 2014, 03:33:12 PM
Remember. A vertical antenna and its radial field is just like a chain—it is no stronger than it weakest link!


Title: RE: Push up pole mounted screwdriver with hamsticks as the ground???
Post by: KE5KDT on April 03, 2014, 04:38:31 PM
Well said Alan.  In this case the weak link is the guy that started the thread.  I just hate it when great ideas meet facts.  Next I want to know if there could be a 6 inch square fractal antenna that covered the HF bands.
Thanks. Bob


Title: RE: Push up pole mounted screwdriver with hamsticks as the ground???
Post by: KG4RUL on April 04, 2014, 10:32:36 AM
Hamsticks are pretty lossy, especially on the lower bands. I don't think they will make a very effective counterpoise for your vertical.

But, compared to other possibilities, that can be readily transported and set up, they are a viable option.


Title: RE: Push up pole mounted screwdriver with hamsticks as the ground???
Post by: KE5KDT on April 04, 2014, 11:11:43 AM
Thanks.  I'm going to try it anyway just for the challenge.  Bob


Title: RE: Push up pole mounted screwdriver with hamsticks as the ground???
Post by: KE5KDT on April 16, 2014, 04:12:07 PM
I bought the materials to make a mount ring for 8 hamsticks and then decided to check with a machine shop.  They wanted way past $120 to make one.  That made the unit from Scorpion Antennas at $85 look more attractive and it would cut out all the work on my end. 
I called Ron Douglass, NI7J, Scorpion inventor/proprietor, and he spent almost an hour talking to me on how to get my antenna and his ring to work together for the best results.  I didn't realize his hamstick mount had a 3/4 inch center hole to match his antenna bases so he offered to craft me a dual threaded nylon mount adapter to allow it to work with my screwdrivers that have 3/8 x 24 threads. 
I am very appreciative of all his help and can easily understand why he gets such great reviews on this site.  My hats off to you Ron and I look forward to getting the parts and reporting on the results.
Bob KE5KDT