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Author Topic: mobile antenna setup  (Read 350 times)
KD5TXX
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Posts: 82




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« on: July 09, 2004, 05:00:28 PM »

This may be a  really easy sounding question but I want to ask.  I currently have a 2m/440m antenna, cell phone mag mount,17meter whip and a 10M whip.  This is on a 2003 Impalla.  Its a company car so no drilling.  Is there any difference in performance in the way that they are alligned on the trunk?  I have them in a straight line accross the back.  Sorry again if it sounds stupid, just got to wondering today.
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KZ1X
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Posts: 3228




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« Reply #1 on: July 09, 2004, 06:24:44 PM »

They are already VERY close together.  Probably have a good bit of coupling ... not necessarily bad, but not necessarily good either.

I'd put the VHF/UHF antennas on the roof, and move the HF antennas apart to opposite sides of the vehicle trunk.  (I assume you're using mag mounts.)

You should try modeling these antennas on EZ-NEC to see how adding them one-at-a-time, moving their relative positions, etc., affects the others.

 

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K0BG
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« Reply #2 on: July 09, 2004, 06:27:47 PM »

There is always interaction. The question is how much? If it's working, don't fix it.

One thing to remember about mag mounts. They will come off in the event of a crash. So far this year, the NHTSA has logged 7 injuries and one death from flying mag mounts. In my opinion, it isn't worth the chance.

I drove OTR for several different companies, and I always drilled holes in company vehicles. I ask first (most of the time), but I always figured after I got through with the vehicle, it was all but dead anyway. One of them, a 72 Ford had 149,000 miles on it and looked like it too!

Alan, KØBG
www.k0bg.com
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WB2WIK
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« Reply #3 on: July 09, 2004, 07:25:01 PM »

I'd also ask about the company car stuff: Does the company really *own* the car, or is it a lease?  If it's a lease, what are the provisions of that lease?

I've driven "company cars" which are really nothing more than leased vehicles for many years, and punched holes in every single one of them.  But not in the trunks, where it would be so obvious: Usually on the roof, where it's a lot less obvious.  I just leave the NMO mounts behind, filling the holes in the roof.  Rarely has anyone ever said a thing about it when I've turned the cars in.

Once, when I turned in my IROC-Z Camaro after the two year lease (and it had a hole in the middle of the roof between the removable panels, with a Larsen NMO mount in it), the dealer actually did ask, "What's that?"  I said, "Oh, that's for my cell phone antenna.  Much better range."  And he was all smiles: "It'll be much easier to sell that way, thanks!"

Of course, a lot of the leased vehicles had such great buy-out clauses prearranged, that at the end of the lease, I bought the cars and then sold them a week later at a profit.  So, the dealer never saw the cars again and couldn't have cared less what I did with them.

WB2WIK/6
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KZ1X
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« Reply #4 on: July 09, 2004, 07:45:51 PM »

"Once, when I turned in my IROC-Z Camaro after the two year lease (and it had a hole in the middle of the roof between the removable panels, with a Larsen NMO mount in it)..."

I remember that car!   Geez, am I that old?

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K1CJS
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« Reply #5 on: July 09, 2004, 09:11:58 PM »

Oh, God, I remember it too!  Guess the old men in the hobby will always be replaced with yesterday's younger men!  ;-)
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KD5TXX
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Posts: 82




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« Reply #6 on: July 09, 2004, 09:17:33 PM »

Yes its leased.  The Cell phone and 2/440 is mag mount.  The 17 and 10 are Trunk lip mount.  I also have a wife who doesn't want to be driven around in a car that looks like an undercover cops.  So they usually come off on the weekend.  I am putting the 10Mon on monday is why I asked.  Thanks
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KZ1X
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« Reply #7 on: July 10, 2004, 11:46:40 AM »

K1CJS wrote "...I remember it too! Guess the old men in the hobby will always be replaced with yesterday's younger men! ;-) "

Oh, it's worse than that.  When I said I remember the car 'WIK wrote about ... I meant THAT PARTICULAR car!  That NMO mount in the roof T-bar was how I learned how one was installed, and then I put one on my own car.  Have used them ever since, probably 50 of them over the years.

Steve and I lived in the same township at the time, only a few miles apart.  He is a few years older than me, and had his own house complete with workshop.  That was LONG time ago ... today, my house has a workship set up quite similarly to his (circa 1980) plus improvements, of course ;-)  It'd be a deja vu if he ever visited me here.
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N3ZKP
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Posts: 2008




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« Reply #8 on: July 10, 2004, 02:11:34 PM »

<<  I also have a wife who doesn't want to be driven around in a car that looks like an undercover cops.>>

Leave her at home.
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N6AJR
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Posts: 9908




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« Reply #9 on: July 12, 2004, 02:51:15 AM »

Try a plate bolted or welded  to the underside of the rear of the cars frame out the 45 degree angle on the driver rear, a couple inches wide and thick enough to be strong, or a piece of angle iron. ( drivers rear is away from the sidewalk, the angle gets it out from behind the car, trees in the center are higher clearance, and it doesn't block the trunk)

if there is no frame make a "sandwich" of the trunk with a plate in the trunk and a plate below the trunk bolted together. then mount a screwdriver antenna there like an atas 120, high sierra or dk3( atas 120 for yaesu rigs $300 and 40meters to 440 mhz) or a mount on both sides one for hf and one for a triband  uhf/vhf setup. no holes..easy, strong enough for any antenna.  no room for a fan dipole

73  tom N6AJR
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