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Old 02-22-2014, 05:03 PM
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DaveInDenver DaveInDenver is offline
Hard Core 4+
Join Date: Jun 2006
Location: Larimer County
Posts: 7,865

Well, I know why my antennas are supposed to be a little shorter than the simple formula says, the patch cable to the duplexer is acting like a transformer. What bugs me is the extra 1/2" or so I have to trim to hit resonance. I can't figure out where it comes from. I have a decent transmission line model so I'm assuming it's in the PL259 or in the NMO on 70cm, even though they are supposed to be impedance matched to 1GHz I just don't buy it.

On your other issue, this is something I preach, lip and fender mounts distort your signal patterns, especially with 1/4λ and 5/8λ antennas. You lose about 3dB compared to the center of a roof in the plane direction and will have very little signal to the non-plane side.

'91 Pickup - Imelda / '08 Tacoma TRD - Donna
'09 Kawasaki KLR650
'98 Rhygin Juke SS / '12 Gunnar Rockhound 29 / '16 REEB Dikyelous

"Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty. Nobody is able to achieve this completely, but the striving for such achievement is in itself a part of the liberation and a foundation for inner security. " --Albert Einstein
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