On Mon, 12 Sep 2005 15:39:23 -0500, Bob Bob wrote:

Hi all.

Throwing together a 20m single quad loop (triangular) antenna. In the
past I have fed these with a 75r Q section. Nothing strange here.. I use
to coil up most of it in a 5" coil to help reduce the line radiation
problem - if any... No tuner in use..

This time however I am going to use two pieces of 50 ohm coax in
parallel giving a 100r balanced Q section feeder. This more closely
matches the loop Z. The shields are joined together at each end of the
section and the coax centre conductors become the two antenna connection
points.

I have a question, Why?

The loop Z is going to be in the neighborhood of 120 ohm. A 75 ohm Q
section is a better deal than 100 ohm.



Question;

Should I be worried about inbalance in the 50 ohm cable from the radio
to the Q section. ie does the Q section reduce any of that problem? If
that isnt the case I can make up the usual coil of coax before it meets
the Q section.. or can I coil up the Q section instead.

I also wonder about Q section shield grounding as I hadnt intended
grounding either end. Will this be an issue?

Cheers Bob W5/VK2YQA