On 10/21/10 10:55 AM, Cecil Moore wrote:
On Oct 21, 8:32 am, Mike wrote:
After taking a good look at the loading coil, its apparent that there
isn't much choice. The bottom of the coil is attached to the lower mast,
and a four pronged plate that the tap wire is attached to at the same
junction. So unless no tap is used, some portion will be shorted/
bypassed or the like.

So which would be better (less lossy) for a 75m Texas Bugcatcher coil
used on 40m? Short out each turn individually or use one jumper to
short out all of the turns that need to be bypassed?


Kinda my original question.

Intuition tells me that ideally - in order of preference:

1. the entire unused portion of the coil should just disappear.

2. A shorting sleeve that renders the unused portion of that loading
coil as a fatter part of the mast.

3. What I have now, a #12 wire from the top of the bottom part of the
mast to the spot that I tuned the antenna. The bottom of the coil is
attached to the same point on the bottom mast.

1. is impossible without having separate replaceable tuning coils. Crazy
inconvenient.

2. This would be the world's fattest screwdriver antenna.

3. This becomes the question? Is this worth worrying about? And testing
would be interesting for each frequency to determine which ones benefit
from shorted/non shorted operation.

Which now leads me to ask, what would be a good way to set up such an
experiment? I guess if follows on that what exactly is the phenomenon
that I would be witnessing? A transformer effect in unshorted condition
certainly would be a problem even for my transmitting equipment?

- 73 de Mike N3LI -