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My Motorhome Installation of a Screwdriver Antenna

Ted (WB2LOU) on February 2, 2007
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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 NS6Y_ on February 2, 2007 Mail this to a friend!
I think the ultimate installation around here would be a good screwdriver type antenna, a High-Q, so I could sit inside and just tune around.......

2nd best is what I have planned....... gotta build the thing then write an article, it has the makings of being one of the "old standards". No it's not a fan dipole!
My Motorhome Installation of a Screwdriver Antenna  
by M0CUQ on February 2, 2007 Mail this to a friend!
As you do not use the antenna mobile why compromise on size? How about using a fibreglass fishing pole as either a full sized vertical quaterwave with radials or as a support for something else, like a 20m delta loop? This set up is only a few dolars. Alternatively, using a fishing pole vertical with an auto-tuner would work on any band. The biggest poles are now up to 60 feet!
My Motorhome Installation of a Screwdriver Antenna  
by KF4HR on February 2, 2007 Mail this to a friend!
Ah Ted, the title of your thread fooled me. I was expecting to see the antenna "on" your motorhome.

But you are correct; trying to find a place to mount a HF antenna on a motorhome is definitely a challenge, especially if you want to operate on HF while underway. That darn 13 foot 6 inch height limitation really puts the kibosh on what "could be" an excellent mobile HF antenna installation! hihi Obviously any HF antenna on a RV is going to be a compromize of some sort.

My goal was to be able to periodically check into the "CARS nets" (EastCars, MidCars, etc), so my installation needed to work while I was underway. What I ended up doing was to bolt on a frame extension which extended out the rear of my motorhome a foot or so, (using a short length of heavy gage steel C-channel). Then with a bit of welding, I attached a bracket onto the C-channel that allowed mounting of a weather-proof pelican box. Inside the pelican box I installed a SGC-231 tuner. A SGC-303 9' whip and mount assembly was mounted on top of the pelican box. In order to keep the SGC Tuner totally protected from the weather (and diesel fumes), all cables entering the bottom of the pelican box were routed through waterproof strain relief connectors. Grounding cables were kept as short as possible.

Does it work? Well, that depends on what band and power level I'm using. On certain frequencies and at higher power levels I get some RF back into the rig (IC-7000) - which shuts the rig down. On other frequencies, and at lower power level, this setup works perfectly. 40 meters was my main goal and luckily that band seems to work fine while underway. It's really great to be able to keep in touch with distant stations while underway, and it's especially fun when openings occur on 10 or 6 meters.

Once I reach a campground I remove the 9 foot whip and attach a long wire. Tuning is very quick with the SGC tuner and because of its memory, the more I use it, the faster the tuning gets. This installation is far from perfect, but it seems to work for me.
My Motorhome Installation of a Screwdriver Antenna  
by N00B on February 2, 2007 Mail this to a friend!
I was thinking mounting a Tarheel #300, on a motorized lay-down mount, on top of our Airstream travel trailer, would put a good ground plane below it.

With regards to your RF problems with roof mounting, does your motorhome have an aluminum roof, or rubber over plywood? Would the latter explain them?
RE: My Motorhome Installation of a Screwdriver Ant  
by K4GPB on February 2, 2007 Mail this to a friend!
Awhile back, several years ago I saw a guyed Buddipole on the roof of an RV on I-95. Have no clue how it worked or how long it stayed attached.

It of course was running length-wise on the roof, a foot or so over the roof.
RE: My Motorhome Installation of a Screwdriver Ant  
by W6TH on February 2, 2007 Mail this to a friend!
With my 30 foot Comfort tilt out trailer I mounted at the rear roof a swivel with a 30 foot vertical aluminum pole laying down. When we camped I would raise the 30 foot vertical antenna and operate with about 8 foot of coax. I found that I could work all bands (9) with the 8 foot length of coax, even with a very high vswr on the coax. However I was using a MFJ 949E at the transceiver end and found the short length of coax had very little effect with the high vswr on some bands. No baluns and rfi was ever noticed. The external camp ground water faucet was the only ground used. The roof was all metal.

At first, also mounted the same vertical on the trailer tong in front with great success, a pipe line to dx.

Several other hams were using the same setups with great results.

RE: My Motorhome Installation of a Screwdriver Ant  
by N00B on February 2, 2007 Mail this to a friend!
I'd considered an antenna mounting post on our Airstream tongue, but unless all the way forward on the tongue jack, it would block the rock shield and front window from opening. What really killed that idea for me was the thought of taking a lightning strike down between two aluminum 40 pound bottles of propane.
My Motorhome Installation of a Screwdriver Antenna  
by AE6CP on February 2, 2007 Mail this to a friend!
Ok, so I don't have a motor home, I'm not an antenna expert but I would try something a little different.

This may not get past the XYL but I think if it were done right, it would not look any worse than a large screwdriver antenna with a cap hat!

Get four one foot fiberglass rods (take an old dome tent support rod and cut the cord to get the individual rods)

Mount one of the 12 inch rods at each of the four top corners of the RV so that they stick up and out at a 45 degree angle (this may take some fabrication but I would look into using the little swivel base for a Panavice, you can get the cheap Chinese version at Harbor Freight, these could be epoxied to the roof to avoid drilling holes)

Then simply run a piece of stranded insulated 18ga flexweave all the way around and feed it with coax and a 4:1 balun. On a 30' RV this would only amount to a loop around 80 feet long so 40m would not work but I might try adding two additional standoffs right in the center of the roof placed about two feet apart in line, one in front of the other, oriented vertically.
I would run the antenna wire along the sides of the RV as before but now instead of running it along the front and back to make a rectangle, I would run it from the corner supports to the center supports, yielding about 122 feet in the shape of a bowtie 31 feet tall and 9 feet wide if you were to look at it from the ladder on the back of the RV. If you feed it with >15 feet of coax, it should tune up on 40m.

I would think half of your signal would be NVIS but the radiation off the sides should be around 45 degrees.
RE: My Motorhome Installation of a Screwdriver Ant  
by WB2WIK on February 2, 2007 Mail this to a friend!
Nice work!

The campsite shown might be common in Florida, but isn't a real common kind of campsite "out west." Most of them out this way don't have nearly that kind of open space, might have crushed stone 6" thick all over, etc. In other words, a more difficult environment for sticking antenna supports into the ground.

I've tried a bunch of stuff on our motor home (32' Class C) and came up with the ultimate solution for me, which is a wire loop antenna elevated above the motor home roof by about 18" using PVC tubing spacers. The loop is about 85' in perimeter and fed with an SGC230 autotuner on the roof (at the loop feedpoint) and then about twenty feet of RG8X to the rig inside. I can open the loop directly opposite the feedpoint to make it a "halo" configuration, or close it to make it a closed loop, to load it up on various bands.

Advantage is, zero "set up" time once parked for camping, and it can be used at 75 mph on the freeway, too.

Disadvantage is, I didn't set this up permanently yet and that will take some time. But experimentally, it works very well and this Spring I hope to have the time to screw and cement it all in place for a permanent "mobile worthy" installation. Cost is obviously very low, and having no set-up time is a big thing for me, since many of our camping trips involve a new location every single night.

RE: My Motorhome Installation of a Screwdriver Ant  
by N8BOA on February 2, 2007 Mail this to a friend!
My RV has a 58 foot horizonal loop suspended above the RV with 18 inch standoffs and tuned with a AH4 Remote ATU. On the ladder is a 33 foot fiberglass pole that holds a wire to make a virtical when in the "Parked" mode. I also run 4 radials on the ground when in the Parked mode. 58 feet of wire mobil not bad
RE: My Motorhome Installation of a Screwdriver Ant  
by KF4HR on February 2, 2007 Mail this to a friend!
WB2WIK - I had a similiar arrangement on my previous motorhome, a 29ft Southwind. But instead of a loop around the top of the roof, I built a wire "L". The PVC pipe enclosed wire went down one side of the RV and across the back. The "L" was fed through a hole in the roof at the front of the L. It worked ok, but not that great. Even with grounding the SGC tuner (the best I could), stray RF was floating everywhere. On certain frequencies I couldn't get the SGC tuner to lock up (constantly searched for a match). I'm betting the steel and aluminum beams that make up the inner roof and side structure of the motorhome are not well grounded and those parts act as radiators at certain frequencies, not to mention the long grounding strap from the tuner.

Also I found trying to attach the PVC pipe to the roof was an interesting exercise. There was less than a 50/50 chance of screwing the attachment brackets into something solid.

Another downside of the PVC/wire approach is, PVC is fragile! If a limb of a tree or something hits it, it'll rip right off your roof, leaving lots of nice holes in your rubber roof. Figure your roof peak is already 11 or 12 feet up. Add 18" for the PVC, and you have a nice target for tree limbs! I experienced this when low hanging tree branches along a country road reached out and made a rainy day, even worse.

The roof PVC antenna idea resulted in a new rubber roof eventually being installed (expensive).

When I upgraded to a larger motorcoach a few years later I decided to go with the Tuner and Whip approach. As mentioned above, this installation has its downsides too, but it sure beats messing up that rubber roof membrain.
My Motorhome Installation of a Screwdriver Antenna  
by AB7JK on February 2, 2007 Mail this to a friend!
Isn't it dangerous to install antennas while drinking? Stay away from those powerlines!
RE: My Motorhome Installation of a Screwdriver Ant  
by WI7B on February 2, 2007 Mail this to a friend!


The key element in your story is the ending...

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

So, good for you! Seeing your screwdriver antenna stuck amongst flagged radiators in a sandy Florida lawn is kinda weird cool in itself.


---* Ken

RE: My Motorhome Installation of a Screwdriver Ant  
by N6AJR on February 2, 2007 Mail this to a friend!
I saw one a while back driving down the road. he had what looked like a hustler 5BTV ( with out the capacity hat) mounted on a pivot at the front end on the driver side of his motorhome, off the left edge of his bumper. this antenna "laid back" at an angle down the side of the vehicle and had like a little U shaped rack with a a bungee cord on it to hold the top of the antenna.

apparently when he stopped, he rotated the antenna up verticle and put in a second pin to hold it upright.

looks like it did ok, although a little close to the body for my taste.

I would have mounted the front end higher for better signal propagation.

it all depends on what you want, I guess...
RE: My Motorhome Installation of a Screwdriver Ant  
by RADIOGUYR2 on February 2, 2007 Mail this to a friend!
till some kid goes back their and plays in the field... sees the antenna and goes over and grabs it... getting rf burns from the thing or trips over the ground wires or the coax cable you put out. You can bet your stay in the park is not going to be a good one when they parents of the kid come a knocking with a 2x4 in hand... for what you did to their kid... event though he was trying to rip it off... I have seen managers walk around and expell people for having wires and antennas out on the ground without some fencing or protections around them. Yours is right on the ground guess who is going to grab the metal part on top that is only 3 feet off the ground.. guess what rf burns from even your 100 watts are going to do to his hands,fingers and toes.. yep toes seem to get it too when your on the gound... can you say you have insurance for medical ... and the attorney that is going to represent the parents and the kid for pain and anguish.. not to mention the trama you gave him now for camping...

locating it away from the vehicle is not very good.

besides... wait till dark and someone comes along and rips it off... yep seen that happen too... they know its got to be worth money at the swapp meet next week.

However, talking about effecency... not very good their either. At best your screwdriver ground mounted is a center loaded whip. Many more antennas that would be much better than that. When mobile and your moving along I can see where its the best you can be... but when your stationary attt wrong answer.

As others have suggested the 1/4 wave vertical is much better... any of the vertical antennas that have traps in them are a second best choice over the 1/4 wave. The screwdriver is the last thing I would choose...

But, this is nothing new. If you go look at the web site for High Sierra or one of the others they show the antenna mounted on a "STAND" which you can then keep the antenna up off the ground.

Last time I was in a campground they didn't allow you to go pounding stuff into their nice green grass.

If you check in QST you will see the article that the other gent did on a setup I had on my airstream trailer... the hustler 5BTV is still the best for the quickest for the buck attached to the vehicle. However, I also now have gone one step further and made up a 5BTV kit that the total lenght of the elements is only 30 inches broken down into sections. easy to put up and quick to assemble... works much better than some of the mobile whip arrangements. Carry in the cargo compartment of the motorhome or trailer... No tuner required on it either so its cheaper.. For ground radials you can use wire.. or just ground it well to the electrical box where the vehicle plugs into the box... I have had good luck with a hose clamp and a wire going to the water spicket also. watch out though as the new places use plastic pipe... underground.

Dipoles are out... so are inverted V's if the campground has kids (which ones don't) in it... as they will be tugging on the guy/antenna wires as well as pushing the vertical pole around... they think its fun... besides the rest of the campers complain that your messing up the sprit of camping when you go putting poles up.. but, we have found that inverted V with the flag on top works... also have the 2/220/440 whip up their so you can have UHF/VHF as well as the inverted vee tuned by the tuner... all in one.. and a flag to boot...

My Motorhome Installation of a Screwdriver Antenna  
by AB7JK on February 2, 2007 Mail this to a friend!
Snowbirds - yuk. Go back to NY. Snowbirds are no longer wanted in Florida. AB7JK
RE: My Motorhome Installation of a Screwdriver Ant  
by K7FE on February 2, 2007 Mail this to a friend!
My motorhome has a homebrew 40 foot motor driven tower that attaches to the rear bumper. If you look at the photo, you will notice that the tower will hold a large Yagi antenna with just three guys.

In the photo you will see a KLM 6 element 10 meter beam in use at Field Day. A Mosley TA-33 tribander works fine also and the tower is "self supporting" at 25 feet. I have also hung a three foot wide (two wire) cage dipole for 80 meters just below the beam at about 38 feet and when fed with ladder line and a tuner, the dipole will cover 80 through 10M.

I use a screwdriver (HI-Q 5-160RT) on the car and love it. It would work fine on the RV as well in spite of the fiberglass, with a counterpoise and/or a few radials attached to the RV.

Terry, K7FE
My Motorhome Installation of a Screwdriver Antenna  
by KD7UEN on February 2, 2007 Mail this to a friend!
We have a "older" class A motor home. I mounted a Don Johnson DK-3 in the middle of the roof just aft of a skylight. I mounted it on a 1.25 in . sq. alum tube going across the roof, a hinge on each end. I have a brace that allows the antenna to lay down enough to be just under 13.5 ft. high. The antenna then is horizontal about two feet above the roof. I am able to talk on the radio going down the road even checking into the noontime net from VY-1 (the Yukon). When parked I open the skylight, (screen out), reach up and stand the screwdriver up, then fold-up a brace to hold it vertical. I use a 102in. whip on the antenna. My radio is a Icom 735 with no extra power. We enjoyed a trip up the Alcan, and I had great contacts to the lower 48 and the Pacific as far as NZ. Another trip across to the East Coast and on to Nova Scotia, making contacts to Europe, South Africa, South America, and friends back in the Pacific North-West where we live. Six time zones, and have a log book half full of contacts with great hams around the world! I am 69 and have been a ham three years. Think I`m having fun with ham radio? Thank you Don Johnson W6AAQ for inventing the screwdriver antenna and sharing it with the rest of the world. My hats off to you Sir.
Ed Sherman K7UEN Port Townsend, WA.
RE: My Motorhome Installation of a Screwdriver Ant  
by K4KWH on February 3, 2007 Mail this to a friend!
A friend of mine mounted his on the ladder, and due to the distance to the frame, etc, was able to get a pretty good result ground and counterpoise-wise. It is up on top of the MH. He uses some heavy thumbscrews so he can set it upright or angle it down almost level with the top of the camper. He fabricated a block of wood with a "V" in it to cradle the antenna when driving and to stow it up on top. It will swivel back AWAY from the body of the bus as well. When laid down, it is almost invisible, but seems to work while down and he can also use it while underway (XYL driving while he plays. Pretty neat, I thot.
:) )


by NXET on February 4, 2007 Mail this to a friend!
So which one works the best. Loop, Vertical, Inverted V, 5btv ?

We went to a campground with the Airstream group, even though we have a Avion trailer. Their we saw lots of different configurations.

Some of them appeared like they drilled a hole in the middle of the trailer roof. Not good for looks.

Some had the antenna mounted on the hitch jack stand. Nice idea.

Some had them mounted on the back bumper of the trailers with extensions that went to the roof line (5BTV) and it folded over for travel on the left side of the trailer. Others used mobile whip antennas in various locations around the trailer. One had two of the High Q mobile whips mounted like a dipole. It didn't work very well. It was rotatable and so it did work that way. Tuneing was done by swr meter as each side needed to be matched. No tuner needed however.

Then we saw the ones that had verticals which went up to 40 ft mounted on the back of the trailers.

Seems that most used a 2x2 towbar hitch mount on the back to which they put the vertical holder like the reciever of the trailer ball.

Some then used it as a tunable vertical with the grounding achieved by putting out radial wires on the ground or grounding it to the water bib. These worked much better than one expected.

Others had wires strung up into the trees and were end fed by a tuner. These worked somewhat well considering the simplicity. For the ground end they too used the water bib. it was rated as the second best. One problem that was noted. You needed a tree and some way to get it up into it.

From that a modification was made to use the 40 ft pole as a center support for a inverted v dipole which could be run up by a rope and pully. (it also has the flag on it too) Way up top was a mobile 2meter and 440 antenna from larson. The bottom of it was what looked like a discone ground radial. This worked good for the repeater contacts and for those who had hand helds which wandered around the park.

the inverted V worked the best of all of them when a unoffical compairson was done.

Another antenna that was noticed was on a motorhome where the owner used plastic sprinkler pipe about 30 inches long. that he had mounted on the sids of the motorhome with broom clips so it just pop'ed in. On the top of these he had a single loop wire that came down and was tuned by a SGc autotuner. it made a horzontal loop antenna around the top of the motorhome which had a fiberglass exterior. it worked almost as good as the 5BTV vert on the airstream. It took more time to put it up and take it down as the owner said it could not be left up while traveling. (too high for bridges)

So which is best. No one made any definate assumptions and it was left to the observer to decide.
My Motorhome Installation of a Screwdriver Antenna  
by WB2LOU on February 4, 2007 Mail this to a friend!
Many thanks to everyone who posted comments. As you read through them, it seems here are as many ideas as there are "hams". This is a good thing and provides everyone ideas for how they might install antennas on a motorhome or at the home QTH. In fact I will be trying some of the ideas myself...I like to experiment !!

As for the comments regarding safety, etc...I am at a closed gate senior park. The park owner oversaw my work and agreed to the plan and asked that I add the flags. The other 95 residents all were informed about the antenna and were requested to not walk in the rear of our site. There are 4 other hams here in the campground who have given me a lot of support too.
RE: My Motorhome Installation of a Screwdriver Ant  
by WB2LOU on February 4, 2007 Mail this to a friend!
Thanks for the negative approach. I subscribe to the positive side and enjoy our hobby where and when I can.
My Motorhome Installation of a Screwdriver Antenna  
by N9AOP on February 4, 2007 Mail this to a friend!
I like your approach as I use an outbacker outreach on an outpost tripod on camping trips. It seems a lot easier than trying to get a good mounting and grounding on the RV especially if you do not ham while you drive.
My Motorhome Installation of a Screwdriver Antenna  
by W4KA on February 5, 2007 Mail this to a friend!

I really enjoyed reading these comments on RV antennas. RF feedback can be cured and these loops sounds very good to me. The XYL and I plan to purchase a motorhome next year,and HF DX is a MUST.
I wonder if I could get the RV builder to help with the RF proofing. My plan is to DX while the XYL drives hi hi. Any one that has had DX success while mobile please add comments to this string.
RE: My Motorhome Installation of a Screwdriver Ant  
by WI7B on February 5, 2007 Mail this to a friend!


Just becasue you ask. i've had pretty good success with Dx while mobile. I use an ICOM rig and an external ICOM high-voltage antenna coupler to drive a 9-foot marine whip. Tunes instanly over the HF spectrum. Work Japan and S. America. Made contact at 70 MPH with E. Kiribati (T32MO) last week.

Safe driving and 73,

---* Ken
RE: My Motorhome Installation of a Screwdriver Ant  
by W4KA on February 6, 2007 Mail this to a friend!

Hi Ken,

Where did you purchase the marine whip? Is there a model number? I'll have to plead ignorant on a high voltage coupler? Exactly what does that do for you? I appreciate your e-mail.
73, David
RE: My Motorhome Installation of a Screwdriver Ant  
by WI7B on February 7, 2007 Mail this to a friend!

marine whip: SCG-303
antenna coupler: AT-140 (Icom)
It RF grounded on on side and high voltage feed on the other (like a Zepp is fed).

Here's a couple photos...



---* Ken
RE: My Motorhome Installation of a Screwdriver Ant  
by XV2PS on February 7, 2007 Mail this to a friend!
Why not to mount it directly on the motor home, even with a clamp type bracket on the ladder or whatever, but possibly more in the middle of the roof. You would have the following advantages:

- Your ground would be the roof,
- None would burn the finger playing/touching around,
- High in the clear,
- Space on the grass free,
- more difficult for thief.

I often use mag mounts for heavy antennas when not moving. To correct the poor ground mag mounts offer, I use a battery clamp (you know that nipper with a spring you use to start a car with another battery) that clamps the base of the antenna above the mount, and make a direct connection to any metal part of the roof (rack,...).

Just my opinions....
RE: My Motorhome Installation of a Screwdriver Ant  
by XV2PS on February 7, 2007 Mail this to a friend!
When mentioning mag mount, could just be some big suckers or anything else, and you add a ground short connection to some metal part of the roof. (your antenna probably cannot fit a mag mount connector).
My Motorhome Installation of a Screwdriver Antenna  
by WB6FQZ on February 9, 2007 Mail this to a friend!
Ted; TNX for the article. I enjoy seeing other hams installations and ideas so I guess I'll add to the fray. My setup is a 30' class A MH and I tow a Jeep Wrangler.The Jeep has a 706 2G with an AH4 auto coupler. This feeds a heavy duty Motorola ball mount with a spring and a 9' CB whip. I usually operate from the Jeep while camping using the whip or if trees are available I put up either a sloper or vertical wire. I remove the whip and connect the wire to the ball mount. The AH4 does the rest and works VERY well. The next experiment will be to use a helium balloon if there are no trees around. As for an antenna for the motorhome. I do not operate while mobile so I set up a tranceiver on the dinette table and use a 5BTV mounted on the ladder. The antenna breaks down into 3 pieces that fit in the rear pass-through compartment for travel. The 5BTV works OK but not great. Being a vertical it needs radials, besides it is very narrow on 75M. As usual it is a continuing experiment while tweeking, improving and experimenting.
TNX again Ted and FB on the positive! It's ham radio, have fun!
RE: My Motorhome Installation of a Screwdriver Ant  
by NXET on February 9, 2007 Mail this to a friend!

this topick came up at the local ham meeting last night. Several of the hams that belong to the Great Sams Hams group put on a slide show with comments. Seems they have tried them all. No one person could agree that any one setup was the best. Each to their own. One had a 40 ft fiberglass sectional pole that had wire wound around it. Another liked the commercial vertical. And yet another liked the simple wire in the tree. Each reported good signals. Eack claimed to be the best for the dollar. One had a fancy folding beam antenna for 20,15,10. lots of personal engineering was shown.

I noticed that most operated while stationary on HF. Underway it was the UHF/VHF ops. While they had cell phones most didn't use them when contacting each other on the road or when they got to the park.
RE: My Motorhome Installation of a Screwdriver Ant  
by W9RRR on February 10, 2007 Mail this to a friend!
I bought our first motorhome about 18 months ago. It's a 38-ft class-A and we snowbird with it. I have been a ham for almost 30 years but not active except in Field Day and Sweepstakes but decided to get active again from the coach.

I bought a 32-ft fiberglas fishing pole and loaded it up. Yep. It works but a bit flimsy and touchy on tuning.

So a G5RV seemed like a good solution. Bought one of those and the next time I parked I was in a tiny little campsite that wouldn't support the inverted vee I had in mind. Waited for the next place to park. Big bushy trees blocked any possibility to put up the Inverted vee again. Waited for the next campsite. No trees, but also not enough space to stretch out the legs again.

Bought a screwdriver antenna and will mount it on the ladder. Hopefully I won't have problems with the RF-feedback when I get it hooked up.

My point is that a motorhome is not the ideal platform for hamming and it's a good idea to be ready for some compromises in performance.

-- Larry
My Motorhome Installation of a Screwdriver Antenna  
by WA6DXI on February 11, 2007 Mail this to a friend!
Take a look at my setup on (WA6DXI), works good for me. The picture was taken on 9/11 thats why the Flag is at half mast, the 4BTV is also a Flag pole and is bungee corded to my rear view mirror. My radial system is 4-6' lengths of 14ga wire.
My Motorhome Installation of a Screwdriver Antenna  
by K4CC on February 13, 2007 Mail this to a friend!
I sold my house and just went full time in a new motorhome. I too just added a Tarheel screwdriver antenna to my motorhome. It works great! I was concerned about looks (new motorhome), interference to the motorhome logic circuits, and simply getting out with a decent signal. I considered mounting on the rear like several others I have seen but opted for the roof since I did not plan to use while driving. This raised the question of a good ground plane and I mulled over the decision for months before I did it. I consulted with my dealer they said it would be no problem to find the metal frames in the roof.

I scheduled it and I was there while they did the work to offer assistance and to make sure there were no unexpected bugs. They did a good job mounting the bracket, sealing the screws and routing and sealing the cables. We tested the raising and lowering of the antenna mount and adjusted it. I then installed the model 300 on the mount.

I had already installed a 200 watt Kenwood 480 and screwdriver controller under the dash of the motor home and mounted the radio on the dash. I figured the 200 watts would help with lack of a beam like I had at the previous QTH. I am using two Alinco power supplies and have them plugged into the inverter outlet.

I have had nothing but good reports on it and I have not suffered any receiver noise like I did with the Ford 7.3 diesel engine in my previous truck. This wehicle has the 11 liter Cummins (525HP). I also have not had any problems with RF from the HF rig into the many circuits in the motorhome.

I have used it on most of the bands and everyone says I have a great signal, especially for a "mobile"!

I also installed a dual band radio for 2/440 and was really lucky when it came to mounting the antenna. There was factory installed cellular antenna mounted on the roof. It was a NMO mount so I used it and installed an adapter for the coax connector to go to PL-259. It works great on 440 but high power on 2 meters get into a couple of the low voltage controllers. I reduced the power and that cured that problem. Since the HF rig does not bother it I am guessing it is the proximity of the VHF antenna to the controller, a foot away.


My Motorhome Installation of a Screwdriver Antenna  
by WB6NYS on February 13, 2007 Mail this to a friend!
After trying several antennas from long wires to "loading the ladder" I decided to use a screwdriver type antenna with a 500 watt amp. I mounted the screwdriver midway up the ladder with a HD Marine clamp-on mount that folded over. 1" pipe will screw right onto the mount and the screwdriver clamps to that. The 40ft RV acts as the counterpoise. Now I can lower the antenna as much as 90 degrees for operating while in motion. Since I tow a car, I don't have to worry about rear clearances. The key to this ant setup is the HD s/s marine mount. Gud reports everywhere...
RE: My Motorhome Installation of a Screwdriver Ant  
by WA6DXI on February 13, 2007 Mail this to a friend!
Why not run your RIGs off your 12 Volt house Batteries?

I ran a 12 Volt line from my house batteries to my RIG.

73s Don WA6DXI
My Motorhome Installation of a Screwdriver Antenna  
by W5AOX on February 16, 2007 Mail this to a friend!
We operate a class C motorhome that, disappointingly, has almost no metal in its outer structure. The skin/outer shell of the vehicle is vinyl, and much of the framing is wood. The only sheet metal in the roof appears to be a narrow strip surrounding the roof mounted air conditioner.
At first I tried mounting my homebrew screwdriver on the front leg of the awning strut. It loaded and worked OK fixed and mobile, but on our first trip out of town I pulled into our rented lot-for-the-night and a tree limb hooked the side of the RV. I heard a thump, and my wife looked out the window and noticed my screwdriver antenna lying upon the ground, dragged by its coax the last several yards into the parking slot.
Then I mounted it vertical on the rear corner of the RV, and made a few trips with it, but noticed the top rod of the antenna must be "interacting" with freeway overpasses, as it continued getting the strangest kinks and "dog-leg" joints in it upon inspection when stopped for gas etc. I also had lots of trouble with "RF-in-the-Shack" when loading up on various bands.
As a defensive mechanism, I tried laying the screwdriver over horizontally, pointing backwards from the upper rear corner of the RV. It actually loaded better, and now does not whack any overhanging bridges or underpasses. To get rid of the "RF in the RV" I added 28 guage insulated wire radials/counterpoises radiating outward across the RV roof and, on the side and corner where the screwdriver itself was mounted, down the side of the RV. The radials are not visible unless you are up close and looking for them, as the roof is too tall to see over and on the side and corner the wire is run adjacent to the trim. Since the antenna is around 10 feet in the air, it does not pose a threat of touching any other vehicle, including semi-tractor trucks. In certain fuel stations I DO have to watch my turning angle to make sure I don't whack a vertical pylon or column while exiting the gas pump. But I can watch that from the side-view mirror, something I was unable to do with it pointing in the more-normal vertical plane.
Being able to operate HF mobile while in motion is very important to me. It helps keep me awake AND while away the miles, making long trips seem much shorter. VHF and UHF are fine for around-my-local-area QSO's while commuting on workdays, but away from home on a trip? Forget it. HF is the only way to find anyone to talk to......
My Motorhome Installation of a Screwdriver Antenna  
by N1NH on February 17, 2007 Mail this to a friend!
I have a 32 foot class A and tow a Jeep Wrangler. I have put off (for 3 years now) installing a screwdrive antenna on the RV. My main interest would be checking into the traffic nets on 80 meters and I can't convince myself that I could reach stations in Florida or mid west on 80 meters with that setup. I'd hate to go thru the trouble and find I couldn't do what I intended to do in the first place. Nice pictures though.
My Motorhome Installation of a Screwdriver Antenna  
by N8FV on February 18, 2007 Mail this to a friend!
OK here is my perspective I am a RVIA Master Certified RV Tech and a fellow ham I have installed many CB and Ham radio setups over the years. First thing to remember is that all RV's are not created equal most modern RV's use laminated wall and ceiling assemblies as such they can be a RF mess the normal procedure is to lay out a aluminum frame work install the wiring and insulation then vacuum lamiunate the interior and exterior wall boards on the roof procedure is similar and then the walls are screwed to the floor and the roof screwed to the walls. The result is a nice looking unit however there are often dozens of stray peices of Aluminum not grounded in the walls and ceiling as such can be tuff to solve. Also in a trailer or 5th wheel you have 2 sources of electricty 120vac and 12vdc in a motor home you have 3 120vac 12vdc from the camper side and 12vdc from the chassis side so be prepared to add a lot of grounds to make it work. I have installed as many as 25 to 30 ground jumpers to get a simple CB to preform well. I recently installed a Predator screwdriver ant on a Class C motor home and it went very well I installed a standoff bracket on the rear bumper and mounted the ant to the stand off I ran a ground from the antenna to the frame I then attached a 50ft lead to my Fluke meter and began testing grounds I attached the long lead to the base of the ant and verified ground to every peice of metal I could find suprizingly I found very little I had to repair this time mostly the standard stuff like window frames which are fairly easy to fix as they are usually just a few inches from a good ground. The procedure is the same for every RV though start with a good idea of where you want the antenna then begin chasing the ground loops and fix them as you tighten up the ground the antenna begins to improve and before long it is as good as any mobile out there. For stationary operation just setup like you would for a feild day and practice good RF safety as most people in a campground are not aware of the danger so use the correct RF guidlines for what you are doing. I have seen several vertical setups such as a 5BTW on a RV roof with the radial system layed out on the roof of the RV these seem to work ok provided you verify the ground integrity of the unit. Just remember that even though you have solved all the problems in your unit does not mean the camper next door has solved all of his so when you make his toaster start talking your stay may be shorter than you planned cause sooner or later they will figure out all the extra wires from your camper have something to do with the problems in theirs.
73's and Good Luck
My Motorhome Installation of a Screwdriver Antenna  
by KC2PNF on February 21, 2007 Mail this to a friend!
I had considered working HF while on the road utilising my trailer hitch. My goal is not to operate while in motion but to fill in the time while stationary. The plan involves buying a second drawbar for the 2" box receiver on my truck. One of those extendable fiberglass poles will go up over 30 feet and the bottom slides nicely over a 1-1/4" galvanized pipe which would be welded to the drawbar. With the trailer off I can swap drawbars and go to town with a screwdriver on top, an inverted vee, or a VHF beam.
RE: My Motorhome Installation of a Screwdriver Ant  
by WX9DX on February 21, 2007 Mail this to a friend!
I have a Predator antenna on my Z71 extended cab pickup truck. It never has fed back into the radio. But I've got the antenna on a hitch mount off the driver's side rear of the back bumper. Like Bob from Indiana the MFR said to do. It's always worked well for me.

Anyway what I was wondering if you'd tried extending the conductor below the coil to make the antenna more efficient. I have noticed that antennas like yours seem to not have the radiation output the longer antennas have. The screwdriver antennas with more conductor below the coil seem to perform better. What other experiments have you done with the screwdriver other than adding ground radials?
RE: My Motorhome Installation of a Screwdriver Ant  
by WX9DX on February 21, 2007 Mail this to a friend!
I failed to mention I'm using a 4 transistor amp I built myself for 10 to 80 meters that works well in the truck. My normal freq I'm on is 3943 and everyone hears me quite well with great reports. Still no feedback RF in my FT100D radio in the truck. BTW, I have a friend that in his motor Home, we used the front Bycycle Rack for a mount for his screwdriver antenna, and it worked out quite well.

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