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[Articles Home]  [Add Article]  

My Motorhome Installation of a Screwdriver Antenna

from Ted Trostle, WB2LOU on August 10, 2019
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"Editor's Note: Due to the popularity of some of eHam's older articles, many of which you may not have read, the eHam.net team has decided to rerun some of the best articles that we have received since eHam's inception. These articles will be reprinted to add to the quality of eHam's content and in a show of appreciation to the authors of these articles." This article was originally published on: 02/20/2007





My Motorhome Installation of a Screwdriver Antenna

By, Ted Trostle, WB2LOU



I have found out over the past year and a half that a motorhome installation of HF antennas is probably the toughest to achieve.

Using a Tarheel Screwdriver antenna, I have tried many different locations on the rear and at the top of the ladder. Even with the best ground, either the ladder or the motorhome itself acted as part of the antenna and caused RF coupling and feedback into the transceiver. The efficiency was so poor, contacts were limited and only a few DX stations were contacted.

Since I do not operate while traveling in the motorhome, I decided that locating the antenna away from the rear of the motorhome was the answer. So I now if we are located at a campground for a while, I will install the antenna as a ground plane with 8 radials about 8 to 30 ft long. I use a good ferrite choke on the control cable at the base of the antenna which stops motor noise and RF coupling onto the cable.

The antenna tunes perfectly and gives me 1.2 to 1.5 SWR across the bands. When band conditions are good, I can work just about any station I hear.

As for operational efficiency, I can only state that because I have made contacts with Europe, mid-Russia, Africa, many South American stations and much of the US with 57 to 59 reports from here in Lake Wales, Florida, the antenna set up must be OK.

I am using only an early model ICOM-706 running on battery power with ferrite chokes on the power leads to quiet electrical noise from the RV appliances, etc.

Overall I am quite pleased with the installation, particularly since I struggled so hard with other configurations that did not work well at all.

Member Comments:
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My Motorhome Installation of a Screwdriver Antenna  
by BOYSCLUBRADIO on August 10, 2019 Mail this to a friend!
Problem is putting it on the ground... radials trip and others see $$ setting out their... not a good placement all the way around... mounting it on the RV bumper / ladder and placing it at the roof line.. is much better... I have seen this before... and if you want check out my article on the 5btv airstream trailer under the call sign WA6CDE for some better ideas...
 
RE: My Motorhome Installation of a Screwdriver Antenna  
by W6SWO on August 10, 2019 Mail this to a friend!
If it works, he's happy, and he's not breaking laws or endangering people, how can it be "not a good placement all the way around"?? Seems like an excellent solution all the way around.
 
RE: My Motorhome Installation of a Screwdriver Antenna  
by BOYSCLUBRADIO on August 11, 2019 Mail this to a friend!
Ok..if you say so... but we have been their and done that and speak from experiance...
 
RE: My Motorhome Installation of a Screwdriver Antenna  
by KJ4DGE on August 11, 2019 Mail this to a friend!
Maybe, just maybe it works just fine for the OP and that is what made him write the article. Yes there are a hundred ways to improve upon something, but he tried it on the RV and it did not work for him, this does. Let him have his fun!
 
My Motorhome Installation of a Screwdriver Antenna  
by W4FID on August 11, 2019 Mail this to a friend!
This is probably a decent working solution to the RV thing. Many RVs -- especially diesel pushers -- have a lot of metal in the back well above ground so any rear mounted antennas have a disadvantage. However there is a problem. Someone tripping over the wires is a concern and potential liability. But the REAL SERIOUS DANGER HERE is even at QRP power anyone touching the antenna will get a poke. More so at 50 or 75 or 100 watts. Much more so if running an amp. Many models of screwdrivers can run several hundred watts and some guys do. Even more dangerous still is if the person touching the antenna is wearing open toe shoes -- sandals or flip-flops are common in FL -- and the skin of your foot is touching ground or if the grass is damp the poke you get will be bad. Even fatal. Talk about liability!!! Personally I would never have a ground mounted antenna that I could not see unobstructed 360* easily from far enough away I could see someone approaching and have plenty of time to turn the transmitter off.
 
RE: My Motorhome Installation of a Screwdriver Antenna  
by K6AER on August 11, 2019 Mail this to a friend!
Can anyone give me a real example of a ham who died touching an active antenna, or one who touched the antenna twice!

Frankly I would have put the antenna on top of the motor home and added some radials.
 
My Motorhome Installation of a Screwdriver Antenna  
by K8QV on August 11, 2019 Mail this to a friend!
What does a ground mounted vertical have to do with a motor home installation? I was expecting some tips for mounting a mobile antenna to such a vehicle.
 
My Motorhome Installation of a Screwdriver Antenna  
by W5GNB on August 11, 2019 Mail this to a friend!
I would think a random long wire and a simple tuner would be far more efficient ~~~ Oh well, if it works go for it !!
 
RE: My Motorhome Installation of a Screwdriver Antenna  
by BOYSCLUBRADIO on August 12, 2019 Mail this to a friend!
I don't know of any who have died.. but a few kids that played in the field where someone like this, who didn't have any conserns except for his own radio operation, got their hands burnt quite badly from the RF when they came over and started touching it without the OPs supervision. As the lawsuit from the parents of the kids said.. the OP put a attractive nuisance item out without any notice or warnings... that cause medical issues with their kids...
Another campground... and the same kind of antenna put out... people who were out on a walk at night came in contact with the coax/ground radials/screwdriver antenna.... one of the elder tripped on it fell and broke her hip... natch the OP packed up and moved out knowing that they were in trouble for ... again not having any per-cautions or warnings out... yep the folks sued the park.. and the park sued the OP... go figure...
Ok guess the rest of us that have seen it happen should just not advise the future ops not to do it... just make sure you have at least 2 mil of personal libilty insurenace.. and your good to go.. put it anywhere you like... if you think radio comes first... and ignore the fact that their are others around you... Works for me
 
RE: My Motorhome Installation of a Screwdriver Antenna  
by KW6LA on August 13, 2019 Mail this to a friend!
On top of the RV with clip-on radials would buy you one S unit ERP?? Would be interesting for the software boys to analyze it. Not to nit pick it. Thank you for sharing your antenna idea.
 
RE: My Motorhome Installation of a Screwdriver Antenna  
by K8QV on August 13, 2019 Mail this to a friend!
Still wondering why this is a "motor home" installation. I guess if I rode my bicycle to a park and erected a ground mounted vertical I could call it a bicycle installation.
 
RE: My Motorhome Installation of a Screwdriver Antenna  
by K9MHZ on August 14, 2019 Mail this to a friend!
You'd think that if he wanted to mount something at ground level, he'd put up a big vertical. There's even a nifty base that you can buy/make inexpensively that allows you to secure it by parking a vehicle wheel on its base and then putting a mast in it for whatever you want to elevate, within reason of course. Even this guy's screwdriver could go up on a mast with a setup like that. Oh well, written 12 years ago, so who knows what he's come up with since then.
 
My Motorhome Installation of a Screwdriver Antenna  
by HA7WX on August 14, 2019 Mail this to a friend!
For RF safety concerns (adults, children touching the antenna whilst transmitting) and also exposure, i would have mounted it on the roof of the motor-home in the clear.
For an antenna, being in the clear is the most important.
 
This is no 50/60 Hz mains power!  
by DL4NO on August 19, 2019 Mail this to a friend!
We are talking about radio frequency. All that can happen is some heat.

The danger of normal a high-voltage installation not there. This cannot happen because of two facts:

- The skin effect prevents the RP power to enter the body.

- There is no electrolytic effect as the current changes the direction so often.

But on thing can happen: burns! The electric power is there.
 
Motorhome and ground plane  
by DL4NO on August 19, 2019 Mail this to a friend!
If you have the room put the antenna to the ground.

The roof of a motorhome is a bad place in most instances: The roof itself is not conductive and it is too small (less than a quarter wavelength in each direction).

Where would you put the radials? Cutting off the heads of all people around?

How do you mount the antenna on the roof?

BTW: If you want to defeat the ground effect, a vertical is the easiest way to go. And a few feet or meters of elevation hardly help. You would need half a wavelength or so.
 
My Motorhome Installation of a Screwdriver Antenna  
by IW5CI on September 5, 2019 Mail this to a friend!
In my RV i use a FT-857 paired with a Yaesu ATAS-100 antenna, perfect automatic swr match from 40 to 6 meters and good performance. The antenna is mounted on the Hood . I used a copper strip to connect the hood to the engine bay.
This is a good solution to work stationary and even while i drive (but i don't use the radio while driving on HF).

screwdrivers antennas are born to be used on the vehicle, not in the grass. If i park che rv on a grass like that, i prefer to rise a fishing rod support with a full size portable dipole with different lenghts.
 
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