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Old October 23rd 06, 10:28 PM posted to rec.radio.amateur.antenna,alt.ham-radio.hf
[email protected] nm5k@wt.net is offline
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First recorded activity by RadioBanter: Jul 2006
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Default Hf Antenna Question


Cecil Moore wrote:
Ian White GM3SEK wrote:
The bunched choke is the one that has a Fmax/Fmin frequency ratio of 6.
A certain amount of mental gymnastics allowed you to claim that 1.5, 2.1
and 2.7 are all approximately equal to 2... so how about 6?


It is a known fact that the VF of these chokes changes
with frequency so they don't behave exactly like a
transmission line. Bunching probably changes the VF
considerably more than a helical wound choke since
the first turn and last turn may be on top of each
other.
--
73, Cecil http://www.w5dxp.com


I've never actually really compared bunching to helical wound.
The one they specify to build for my triband yagi is a helical
coil. On that antenna, I've used both methods, but not at the
same time to really compare. I didn't notice any real noticable
difference in operation though. I was just looking at the small
choke in my trunk for 2m. It hangs from the trunk lid, and is
tie wrapped. It was about 2-3 diameter, and about 4-5 turns
or so, bunched together. For the purpose I used it for, it
worked great. But it could well be possible what you say about
the higher frequency operation. I do know a bunched choke is
a whole lot better than no choke at all.
MK
MK