Highland Ham wrote:
Why not replace the complete coax feeder with twin lead feeder (if you
can keep it away from soil and/or metal) , and use a matching box
directly accepting the twin lead feeder ( without ferrite type balun),
be it 300 or 450 Ohms or approx 600 Ohms ladder line ?
It will improve efficiency and above all make the antenna multi-band.

Let's see how much improvement. Assuming a 50 ohm antenna,
3.8 MHz, and using Owen's xmission line calculator at:

http://www.vk1od.net/tl/tllc.php

85 feet of RG8x has a loss of 0.478 dB.

85 feet of 300 ohm twinlead has a loss of 0.424 dB.

How much will that 0.054 dB improve efficiency? 1%?

The coax has a 1:1 SWR. The 300 ohm twinlead has a
6:1 SWR. That makes the losses almost equal. If we
were talking about RG-213, the losses would be
0.308 dB, 0.116 dB better than the 300 ohm twinlead.

The following is becoming a myth: "One can ignore
the losses in twinlead and ladder-line."

Also - maybe he doesn't want to use a "matching box".
--
73, Cecil http://www.w5dxp.com