[Hondaman]

Okay, when I replaced the wire (10 or 12 gauge in the US system would be metric 4.0 or 6.0 square mm cross-section) on the main antenna with 0.25 inch copper pipe, the antenna did not give any better performance, but I put it back in my attic.

When I ask my TV to tell the "percent signal" (very un-scientific) on Channel 11 (198-205 MHz), the "T" antenna (29-inches, 10 or 12 gauge wire) DID outperform the 58-inch "T" made with copper pipe. So I put the 29-inch wire "T" back in the attic as well. This time I hung it up, and it is 30 inches higher than before.

So all TV stations are now at 97% signal except for WHAS Channel 11, which hovers around 90-92% in clear skies. This is as good as I will ever get.

EDIT: I made sure both the antenna and the "T" antenna had the same length of RG-6 going into the splitter/combiner to prevent signal from one antenna "backfeeding" into the other which would have hurt performance terribly.

(It also seems that the metal mesh reflector screen did not help things. I was using a temporary crude "bowtie" with no reflector screen and a 29-inch "T" for Channel 11 and got the very same results on all channels that I am seeing now.)

The attached picture shows the old wire version just after I finished building it at the end of March 2008.