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Author Topic: operating "mobile stationary"  (Read 677 times)
KD5UCM
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Posts: 12




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« on: November 29, 2007, 09:41:57 AM »

I will doing some environmental work in West Texas late this winter thru early spring.  The group will move camp every few days as we work thru the area.  I plan to just leave the radio in place in the vehicle as well as the 108" whip.  The whip will be mounted on the roof of a Suzuki Sidekick at the rear corner.  The plan is to run radials for 10m, C.B. (the others use C.B.), and the CW segment of 20 and 40m.  Should I drop a wire to the ground and drive a ground rod and run the radials from that point or just run them from the base of the antenna and slope them out and secure them with stakes?  I question the value of a ground rod because of the poor ground conductivity in these areas.  The whip will be extended as much as necessary with wire or a second whip.
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K0BG
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« Reply #1 on: November 29, 2007, 01:35:22 PM »

Actually, running radials that far removed from the actual antenna isn't going to help much as far as ground plane losses are concerned. You didn't state what you're using for a radio, but you should be using an amateur radio on CB. That isn't legal.

If you're using an auto-coupler to drive the whip, you're not going to get very good performance on 40. In that case, you'd be better off with a long wire.

Alan, KØBG
www.k0bg.com
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W3LK
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Posts: 5639




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« Reply #2 on: November 29, 2007, 02:22:26 PM »

< < but you should be using an amateur radio on CB. That isn't legal. >>

That should read SHOULDN'T. Smiley

73,

Lon - W3LK
Naugatuck, Connecticut
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KD5UCM
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« Reply #3 on: November 29, 2007, 02:48:08 PM »

No, not using amateur equipment on cb.  Actually had to buy one, first I've ever owned.  And, for the purpose it appears to work quite well.  Very inexpensive, 23 bucks new.  Where this research group works is very isolated, no cell service, no repeaters in range, maybe 40-60 miles to nearest residence.  They needed a way to communicate between work groups and cb was the cheapest and most effective way to do it.  They only needed to cover a few miles.  Volunteers have to supply their own.

The radio will probably be an FT-857D.  I understand that the use of radials on a mobile rig is common place in Africa. Seems like I remember the U.N. and missionary groups doing this to improve marginal situations. I'll try it and find out.  Just wanted to see if anyone had actually tried it.

Thanx for the replies.
73, KD5UCM
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K0BG
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« Reply #4 on: November 29, 2007, 03:44:49 PM »

My fingers don't work like they used to. So, it's nice to know there are folks watching your backside for you. Especially esteemed ones.

Alan, KØBG
www.k0bg.com
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KB5TJ
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« Reply #5 on: November 29, 2007, 07:43:20 PM »

What about 3 drooping 'ground' radials, 108" long each, spaced 120 degrees apart, staked to ground but *insulated* from ground.  The vehicle is a wildcard, but on 10/11 meters this would seem to approximate an elevated vertical.  I have no idea what the coupler would think about it on 20M, but shouldn't it at least increase image plane capacitance to ground?

Mark
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W3LK
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« Reply #6 on: November 29, 2007, 07:50:27 PM »

<< So, it's nice to know there are folks watching your backside for you. >>

And it's an ugly one, too! <g>

I'm in the process of unpacking the rigs and getting the shack set up in my new home. Sure wish you were here to do it for me! Smiley

73,

Lon - W3LK
Naugatuck, Connecticut
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KB5TJ
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« Reply #7 on: November 29, 2007, 08:04:55 PM »

Plan B -- space the drooping ungrounded radials 90 degrees apart, let the vehicle act as a 4th radial.
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WW5AA
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« Reply #8 on: November 30, 2007, 09:42:41 AM »

You would be better off just clipping a wire to the whip and tossing it into a tree or supporting it on a break-down fishing pole. Unless your vehicle is poorly bonded, the radials will not do much for you.

73, de Lindy
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AC2RC
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Posts: 112




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« Reply #9 on: December 01, 2007, 03:20:46 PM »

With my whip and tuner the easiest way to get a better signal when parked is to add wire to the whip.The vehicle is the ground.If you don't have trees one of the take apart whips made for boats by Shakespeare could do the job.
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KG0SH
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Posts: 4




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« Reply #10 on: December 01, 2007, 10:17:48 PM »

The majority of my operating in the last few years, other than bicycle mobile, has been what you call "mobile Stationary".  I've found that trying to ground my truck is a lost cause.  I've experimented with adding elevated radials but that didn't seem to help much either.  I'm not always around any trees, which sounds like you might be as well in west TX so throwing up a dipole or long wire is also tough.  

One thing that worked for me was a buddipole stuck up about 20 feet on a simple mast.  I used a drive-on mast stand that worked great.  No real need to ground anything.  What works even better is a 2 element StepIR beam mounted on the trailer hitch but that is a different story.

One tip I can pass along.  Paint the drive on stand very bright colors.  It gets your attention when you drive away and forget it!

73,

Bruce KG0SH
Golden, CO
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KD5UCM
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« Reply #11 on: December 02, 2007, 06:11:16 AM »

Thanks for all of the replies and information.  I was hoping someone had some "magic" way around the physics and common truths on this one.  *sigh*.  Guess I'll accept the advice of the masters and just build one of the many portable verticals with jumpered coils from the handbook.  I've been cultivating a lazy streak lately and the idea of just tossing out a few wires was captivating.
Thanks again and 73's,

KD5UCM
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ONAIR
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Posts: 1744




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« Reply #12 on: December 07, 2007, 06:16:08 PM »

     What CB unit did you buy for $23 bucks, and where?
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KD5UCM
Member

Posts: 12




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« Reply #13 on: December 09, 2007, 04:47:53 PM »

Try newegg.com .....it's important to enter "cb radio" in the search box or you won't find them.  I buy a lot of computer parts from these people....never been disappointed.  They have the Midland 1001z for $23.99- Mine works fine.  Still, you get what you pay for.  It doesn't have all the bells and whistles of a $150.00 radio.
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