Hal Rosser wrote:
If I recall, a full wave loop has an impedence of about 100 ohms, so if you
feed it with an electrical half-wave length of 75-ohm coax, you should have
an acceptable match, and a decent vswr.

Methinks you meant *quarter-wave* length of 75-ohm coax.
A half wavelength would merely repeat the feedpoint
impedance.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

In message , Cecil Moore
writes
Hal Rosser wrote:
If I recall, a full wave loop has an impedence of about 100 ohms, so
if you feed it with an electrical half-wave length of 75-ohm coax,
you should have an acceptable match, and a decent vswr.

Methinks you meant *quarter-wave* length of 75-ohm coax.
A half wavelength would merely repeat the feedpoint
impedance.

The question is, "Do you use a quarterwave of 75 ohm cable to get
something like a 50 ohm impedance at the TX end - even if this means
using more coax than you really need or, to minimise losses, do you
simply use the shortest length of coax - either 50 or 75 ohm?"
--
Ian

Ian Jackson wrote:
The question is, "Do you use a quarterwave of 75 ohm cable to get
something like a 50 ohm impedance at the TX end - even if this means
using more coax than you really need or, to minimise losses, do you
simply use the shortest length of coax - either 50 or 75 ohm?"

Usually not a problem since 1/4WL of RG-11
at 4 MHz is only ~40 feet - hopefully less
than the height of the antenna. 1/4WL at any
higher HF frequency would be shorter than that.
Excess coax can usually be coiled into a choke.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com