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Originally Posted by Russ D
Aha, perhaps it's the length of his coax then, I was always told it should be multiples of 7 feet - we'll try 25 and a half feet instead then.
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I'm not really sure where that myth started about the length of coax. If the aearial and feed system is matched to the transmitter it shouldn't make any difference, however if there is a mismatch you will get standing waves on the coax with high voltages/current at odd wavelength multiples on the coax. I think it really only comes into play when a system is not correctly matched, also in the ideal world you wouldn't connect a dipole direct to coax because the coax is 50 Ohm and the dipole has a nominal impedence of around 72-75 Ohm. (covered it cos I can't remember) also the dipole is a balanced device and the coax is unbalanced, so in the ideal world we would fit a unbal-balance transformer at the aerial feed point, failure to fit this also affects the radiation pattern of the aerial.
I think just connecting your 8 and a half foot per side or whatever to a piece of coax should prove the point, just ignore me being bl**dy minded again.
