[AMRadio] Thank You and Toroidal transformers


Ed Sieb esieb at sympatico.ca
Fri Dec 29 08:42:05 EST 2006


Any Pi-network final should match it fine. The SWR is only 1.5:1 with a 75
ohm-50ohm coax mismatch.  In fact using 75 ohm coax for a dipole is correct.
The pi-net in the rig will easily handle that.  A solid state rig  can also
handle the mismatch without a problem.

You'll need an "unun"  that goes from 75 to 50 ohms.  The problem is that
transformationis so small that I've never heard of one being commercially
available,(try Radio Works, http://www.radioworks.com/ ), they might have
one, but I doubt it.  You don't need one anyway, as the transformation is
too small to worry about.

Ed, VA3ES
--------------------------------------------------------

Pieter Gerlach wrote:
As an added favour could anyone tell me what sort of toroidal core i would
need to transform 75 to 50 0hms. I was given a large quantity of CATV
hard-line and read that it would be well to match the impedance to the
antenna and the transmitter. Or do you think the Pi-network in the P.A.
would be able to match the 75 ohm? I would at leat like to know which cores
from Amidon would be the right ones in case i just want to construct a few
transformers for experience sake. Thanks so much for any help you can give
me.




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