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Old April 24th 06, 04:23 AM posted to rec.radio.amateur.antenna
 
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Default mobile loading coils


" wrote in message
...
I want to build some mobile antennas for 10 15 and 20 meters but I am
having trouble with the physical design of the coil. My biggest problem is
finding readily available material. A shopping list of things to get at the
Home Depot would be nice. Antenna would be mounted on my pickup tool box
and would like to keep them six ft long so they will fit neatly in the back
of the pickup when not in use. I tried this about a year ago and got the
antennas to work but the PVC loading coil forms came apart after a while.
Any help would be greatly appreciated.


I put together the 15m and 10m antenna today. 10 meter is OK,15 and 20 meter
units have a really high SWR, nearly fullscale on the meter which reads 5:1
max. I figure this may be normal as the impedance of the shorten antenna
should be getting pretty low at this point. 10 ohms or less would not sound
to unreasonable to me for a 6ft long 20m antenna.

I went to the Home Depot today and found some chimney sweeper brush handles
.. These are about 4 ft long each made of fiberglass and screw together. A
few of these in the back of the truck will allow me to put together nearly
any length antenna I need. Im thinking 40M may be a practical limit Dont
worry I dont drive and ham at the same time.

Worst problem I see with this is making an adapter for my ball mount. Will
probably cannibalize one of the handles for its attaching hardware and weld
a bolt to it to fit the ballmount