Mobile antenna extender

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FakeJake
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Mobile antenna extender

Post by FakeJake »

Anyone know where I'd get something like this? Due to the antenna mount location on the car, antennas appear electrically shorter than they are, e.g. My CB antennas appear to have a very low SWR at 29mhz, great for 10m, but not 11m, and my 4m antenna is quite off the mark...

SO239 or 3/8 fittings would be ok

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Admiral
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Re: Mobile antenna extender

Post by Admiral »

If these go before the electrical winding rather than after, would they not effectively extent the feedline and not the antenna, therefore making very little difference to SWR?
Just thinking out aloud.
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FakeJake
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Re: Mobile antenna extender

Post by FakeJake »

Even if they did, that would improve things by getting the loading coil away from the bodywork of the car.

If the extension has the pl259 fitting, you could theoretically have 50ohm coax go up the mast to the antenna and the antenna would begin at the actual antenna. If it's just a metal whip (as it would be if it has 3/8 threads) then it's actually adding length to the antenna.

That's my understanding of it anyway, I stand to be corrected!
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Mitch
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Re: Mobile antenna extender

Post by Mitch »

How much longer does it need to be? Perhaps a quick release mount would extend it enough, or just get a longer whip. If you're static mobile then extra ground planes could do the job.
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Retrodog
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Re: Mobile antenna extender

Post by Retrodog »

Admiral wrote:If these go before the electrical winding rather than after, would they not effectively extent the feedline and not the antenna, therefore making very little difference to SWR?
Just thinking out aloud.
It's shouldn't, once the 50 ohm feed splits at the mount whatever is fed afterwards becomes part of the effective radiating element.
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Unit 148 Mobile
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Re: Mobile antenna extender

Post by Unit 148 Mobile »

Jake,

Did you sort out your antenna issue?

You did not state antenna make.model and the antenna mount and location.

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FakeJake
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Re: Mobile antenna extender

Post by FakeJake »

Ended up just moving the mount location (using a smaller mount to attach to the top of the hatch)
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