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Old 06-28-2014, 09:29 AM   #11
wa8yxm
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Originally Posted by NN5I View Post
Me, I like to operate HF while in motion. Can't do that with a wire over a tree, unless the wire is rather long.
The nice thing about the KAT-1 Tuner is it can use a multitude of different length wires,, 83 feet over tree limbs is my favorite. 50 feet run from a fishing pole to a flag pole one mounted on the rear of the RV and the other in a "Park on base" under the right front tire (The pole will also hold a flag in a few days) is the current antenna. On the road there is a bit over 30 feet of COPPER TUBING with a CB sprial wound on the end of it about 2 inches above the roof, Does not work well on low bands but actually better on the higher bands.

That said,, Mobile I use mostly VHF/UHF since I do not care for tuning.
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Old 08-16-2014, 02:54 PM   #12
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You have your antenna mounted too low on the vehicle..

The maximum amount of current is at the base of the antenna and the tip of the antenna has the least.
When you mount the antenna low - most of the signal ends up underneath the vehicle.

A better suggestion would have been to mount the antenna in the middle of the roof and build a tip up antenna mount. Drive to where you are going and then tip it up and operate...

Even if it was at the rear of the vehicle and high - it would talk several times better then where you have it.
I'm surprised that you aren't complaining about a high SWR ...
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Old 08-16-2014, 04:48 PM   #13
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Me, I like to operate HF while in motion. Can't do that with a wire over a tree, unless the wire is rather long.
Just drive faster!
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Old 08-16-2014, 04:54 PM   #14
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Originally Posted by Mr. Ham View Post
You have your antenna mounted too low on the vehicle..

The maximum amount of current is at the base of the antenna and the tip of the antenna has the least.
When you mount the antenna low - most of the signal ends up underneath the vehicle.

A better suggestion would have been to mount the antenna in the middle of the roof and build a tip up antenna mount. Drive to where you are going and then tip it up and operate...

Even if it was at the rear of the vehicle and high - it would talk several times better then where you have it.
I'm surprised that you aren't complaining about a high SWR ...
I agree with you at least the coil should be in the clear but the motorized antenna pretty much will match any thing however the efficiency will be pretty poor. A screw driver antenna is pretty much magic any way they really should not work worth a hoot but they do.
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Old 08-16-2014, 04:55 PM   #15
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You have your antenna mounted too low on the vehicle.
And I suppose, if I mounted a ground-mounted vertical in my back yard, you would complain because it was ground-mounted instead of elevated. But when one elevates a vertical monopole, one must also (usually) install elevated radials so that the antenna will be mounted near its ground plane. Therefore, nonsense, say I.

If it were on, say, an all-aluminum trailer, you would be nearer right, for (with the antenna mounted low) the aluminum body would tend to block the signal (and also detune the antenna by bypassing it capacitively). But my motor home's body is mostly fiberglass and, for RF, doesn't exist.

This antenna is some 10-12 feet tall depending on frequency. I can see it now, mounted on top of my 12-foot-tall motor home. I would have to use a tilting mount if I ever wanted to go anywhere, and certainly couldn't operate when moving. Also it wouldn't work worth a flip anyway, being some 12 feet above its ground plane (the frame of the vehicle). That's more than 1/3 of a wavelengh at 20 meters.

But thank you for your advice.
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Old 08-16-2014, 04:58 PM   #16
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I'm surprised that you aren't complaining about a high SWR.
Perhaps there are other surprises in store.
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Old 08-18-2014, 10:53 AM   #17
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NN5I - you would be better off to put it on a Christmas tree stand and deploy it when you are destination, and then throw out a loop of ground radials.
People may refer to you as that nutty old ham that likes to camp by himself, but you would have a much better signal that way...

Had it been say a YUGO - the body would only be about 4' tall, not a lot to worry about if the antenna was mounted 2' off the ground.

I don't operate much mobile, especially while dragging a trailer around...
Too many dumb people on the road, talking on their cell phones / not paying attention, trying to cut you off, or thinking that you can stop on a dime if they pull out in front of you or stop all of a sudden.
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Old 08-18-2014, 12:53 PM   #18
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NN5I - you would be better off to put it on a Christmas tree stand and deploy it when you are destination, and then throw out a loop of ground radials.
People may refer to you as that nutty old ham that likes to camp by himself, but you would have a much better signal that way...

Had it been say a YUGO - the body would only be about 4' tall, not a lot to worry about if the antenna was mounted 2' off the ground.

I don't operate much mobile, especially while dragging a trailer around...
Too many dumb people on the road, talking on their cell phones / not paying attention, trying to cut you off, or thinking that you can stop on a dime if they pull out in front of you or stop all of a sudden.
You're mostly right, except that people already refer to me as that nutty old ham.

I don't drag a trailer around; I drag my toad, a little Ranger pickup that might as well not be there for all the effect it has on driving the motor home.

My motor home is mostly invisible to RF, which is why the antenna can be low.
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Old 08-18-2014, 06:35 PM   #19
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Carl, how efficient have you found your rear (and low) mounted antenna to be? I had an auto tuner, ball mount with 8 foot whip clamped to the rear bumper of my Class C and could not make one qso on 75, 40, or 20 during a road trip a couple of years ago. I grounded antenna to the RV chassis at the rear. Also, mounted a Tarheel II on the left front fender with similar lousy performance. Got lots of RFI from engine. I'm sure the plastic hood on my 2006 Chalet E350 didn't help.

I'm still looking for a practical installation for HF "in motion" communication.

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Old 08-18-2014, 07:04 PM   #20
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I some times remove the TarHeel from the truck and mount it on the camper (roof height) the roof is aluminum and it works pretty good. It's mounted on the rear of my pickup by the tail gate and works great there also. Camper antenna-- 10,12,15 and 17 meters pictured at 17
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