One thing I have yet to try is running a pair of 75 ohm, with both coaxal
shields tied together, with the shields grounded in the shack...in lieu of
the 400 ohm feeders...to the outside 600 ohm feeders.
I have heard of useing two pieces of coax to make balanced feeders in
this manner before. I am sure that it can work, however I wonder what
you lose when you do this. It seems to me that you would now have the
voltage limitation of the coax, (or perhaps 2X that from hot lead to hot
lead) and you would also have additional loss due to the dielectric
being other than air as with open wire feeders. The current handling
capacity would also be lower due to the center conductor being enclosed.
At amateur power levels and at HF frequencies I doubt that the reduced
current handling or the dielectric loss would be noticeable. The voltage
limitation may be a problem though.
I am interested to hear any first hand experience using dual coaxes
balanced feed lines, especially at higher power.
N6KB
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