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Author Topic: Diamondback tonneau  (Read 532 times)
AC2RC
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« on: July 20, 2009, 01:26:27 PM »

I'm getting a new F150 but this time with a www.diamondbackcovers.com tonneau.It seems the best place for a AH-4 + whip or screwdriver would be the center section of the tonneau.Does anyone see any problems with this ?
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K0BG
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« Reply #1 on: July 20, 2009, 02:39:33 PM »

Yep! Under the right conditions, the output side of the coupler will have as much as 10 kV of RF, which will arc to just about any material, even plastic.

Mounting it in the middle also makes a proper ground connection next to impossible. The ground connection (not ground plane mind you) needs to be short; inches not feet.

Go to my web site, and read the Antenna Couplers article.

Alan, KØBG
www.k0bg.com
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AC2RC
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« Reply #2 on: July 21, 2009, 08:44:07 AM »

I've had a stake pocket mount with AH-4+whip for years without problems so with proper delrin etc I could make that work. Short hot to antenna and short ground to tie down ring.
However , though I've read your excellent website many times I'm confused by the comment that the ground wire must be short.Hot side yes but ground also ??
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K0BG
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« Reply #3 on: July 21, 2009, 03:40:27 PM »

The start of the ground plane is where the coax shield connects, and that point should be coincident with the ground connection of the coupler. This is of extra importance as the coupler-whip combination is the equivalent of a based loaded antenna, and keeping ground losses low is essential.


Alan, KØBG
www.k0bg.com
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