Actually I got your point and I wasn't meaning to prove anyone wrong with my post, I was just adding information concerning baluns to those reading and possibly trying to show a little about why people wrap coils of coax under their antennas...I obviously left out a lot more information but stated earlier I wouldn't go into great detail on the subject...Not everyone uses a balun or air choke and yes if you coil your coax in such a fasion that the beginning and ending leads of the coil are close you will end up frying some coax using moderate to high power, but if you evenly space your turns out so that the beginning and ending coax leads don't get put together like they would if you was rolling up an extension cord then you should be fine up to several hundred watts...So I didn't mean to ignite a feud between you and Mr Monster...I don't know either one of you so I'll keep my opinions to myself until the time come for me to let them out...Thank you
Last edited by Moonchild 747; 05-09-2013 at 09:16 PM.
de 747 and I'm clear...
"He who controls the electromagnetic spectrum controls the world..."
BUMP BUMP.
Yeah, a little old but still an interesting thread, just thought I'd add that you are ALL fairly correct.
I prefer not to call a 'Common-Mode-Current Choke' (cmcc) a "balun", but balun DOES mean "balanced to unbalanced", usually attributed to a coax fed dipole, where both sides of the wire or tubing making a dipole are of equal length - therefore 'Balanced'.
When you go from coax (unbalanced) into the match of an antenna, a cmcc is also a good idea, as long as it's at or very near a current node.
The reason a cmcc tends to heat up is because there's a mismatch at the antenna, often at the 2nd or 3rd harmonic which poorly aligned radios, (increasing of course when amplified, especially those with spread harmonic filter coils!) tend to create at much higher levels than they should,
- plus the coax often happens to be cut to a resonant length for one or more harmonics so it ends up being a 'friendly load' for the harmonics on the coax casing, and all that 2nd or 3rd harmonic wattage is being only partially stopped by the correctly wrapped for the fundamental freq choke, then heading up to an antenna, usually with a DC ground shunt tuned for only the fundamental frequency which acts like a DC short to harmonics, causing heating & molten DEATH to feedline.
Keep the radio clean & aligned and your amplifier won't be bogged down trying to also amplify 54MHz, 81MHz, 108MHz etc., causing high SWR and heat.
At least that's what some CBr told me
Last edited by JAFO; 08-17-2015 at 02:45 PM.
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