On Wed, 21 Apr 2004 05:40:11 GMT, zeno wrote:
You remind me that I do not understand something. Let's say the
characteristic impedance of this 540' loop is in the neighborhood of 140
ohms in free space, or even as you say closer to even 35 ohms in reality.
Your point was, if I understand correctly, that this is in the ballpark
of 50ohm coax and you suggest it can just as easily be fed into the coax.

But I thought that coax is unbalanced and the point was to go with a
balanced feed line?

Hi Bill,

True, but easily answered with a feed line choke (1:1 BalUn) at the
drive point that will render the coax balanced if the load is - being
that close to ground there is every chance that may be debatable.
Again, there is no getting it right the first time out of the box -
you can only put it up and test to see how much you need to change it.

You were planning pulleys right?

I guess I am not understanding the relevant differences between balanced
vs. unbalanced feedlines, and getting the impedance of the the
transmission line close to the impedance of the antenna.

You can build a twin line of 50 Ohms. Takes pretty close spacers, and
you will need a lot if you use bare wire. The wire pairs would be as
close as zip cord. Twisted pair, insulated could do the trick (might
even match the 35 Ohms).

I thought the point of my striving to use balanced ladder line was to
somehow gain something that would be compromised by using coax. I thought
that the the ladder line which might be 488 ohms say is still going to be
a better feedline than using the 50ohm coax.

Well.... Only if you use this as a monobander. As a multibander it
will ALWAYS have SWR, the point of big wire twin lead is that the loss
will be less than if you used the same antenna with coax feeding it.
Coax with big center wire is HUGE and COSTLY for the same loss figures
at the same SWRs met by multiband use.

For 160M band, I would REALLY look for the Archer and put my effort
into that prospect. A low loop is the pits - hi Z, lo Z, balanced,
unbalanced, SWR, no SWR hardly counts for diddly.

The coax would still then
require a balun, correct? (a 1:1 banlun?).

ibid.

It is sites like this: http://www.cebik.com/par.html that tend to get
one thinking about this whole diy approach.

My reading and gleaning of websites has me of the opinion (at this point)
that the balanced line with this long loop is better (multi band) than to
feed it with coax.

True enough. I simply responded to you describing it as a 160M loop.
If it was a dedicated monobander, twin lead is extravagant and forces
unnecessary SWR into the picture.

I believe Cecil has already explained this in terms of the wide range of
actual resistance that may be encountered multi band. (hey, I am just now
learning to talk this lingo....just barely know what I am talking
about....operating intuitively, and with the kindness of strangers.......

Stella! (Oops, wrong "Streetcar").

73's
Richard Clark, KB7QHC