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Installation problems with screwdriver antenna on cargo trailer

Mar 29th 2013, 03:06


Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I am in the process of installing a Scorpion SA-680S screwdriver antenna on the roof of my cargo trailer ham shack.
The antenna is mounted to a mechanism that will raise the antenna from a horizontal position (stored for traveling) to a vertical position for stationary operating purposes. The mechanism is powered by a linear actuator that has internal limit switches which limit the maximum throw of the actuator shaft/plunger. I do not believe they are adjustable as I have no data on the SuperJack II+.
I am unsure just what to call this equipment due to not knowing the proper names for the components or the total package. Here are some photos to give you an idea of what I am dealing with in this installation.

Try this one first:

Or this one....

It appears that I do not have adequate adjustability to have the articulator move the antenna from an appropriate (slightly above horizontal) horizontal position to a proper vertical position without putting a limit switch in the control line. I would like the antenna to be inclined a little from the horizontal to avoid rain from running down the antenna and in and under the top section and into the coils. I could use some ideas on what switch to use and how to wire it. It seems that a diode is needed to make the system work and I have no idea at this point what the current requirement of the diode would be needed.
I am running the control wiring about 30-35 feet from the station to the antenna. I am concerned about voltage drop and what size wire to use in this 12 volt run.
I do not have any specifications on the SuperJack II+ HQ linear actuator and hope someone has those specs.
I will appreciate any and all suggestions or advise anyone may offer.
Mar 30th 2013, 13:31


Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
This page has specifications--ignore the initial blank screen and scroll down.

Some folks find it helpful to build a simplified model--while it does take some time to build a functional model, models may allow you to cheaply decide which of several options is best.

Zack Lau W1VT
ARRLSenior Lab Engineer
Mar 30th 2013, 18:47


Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Some Googling reveals that Terry NZ5E has built something quite similar.

I think he even wants to know how well his idea would work with your antenna!

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