wrote in message
oups.com...
Ken,

I guess that you are using the T-connector simply as an elbow? If this
is the case, and you put a 50 ohm load on one leg, you should leave the
other leg *open* to make the impedance be about 50 ohms. The
T-connector will give you a little bit of capacitance due to the
concentric conductors on the unused leg, but it will make little to no
difference until you hit UHF or so.

If you put 50 ohms on one leg and a 50 ohm load on the other, Amos's
post will apply. The impedance seen by the transmitter will depend on
the length of transmission line between the T and your transmitter.
This is because the line between the T and your transmitter is no
longer properly terminated at the T end.

With very short transmission lines, the situation is just like parallel
resistors. This means that the two loads on the T will share the
power.


Regardless of the T-line length, it will be a 2:1 mismatch. If the line
is 1/4 wave long, then the Tx will "see" 100 ohms.

Leaving one end of the "T" open will provide no significant effects up
through UHF, but it does represend a very short section of open line in
parallel, which, as Dan reports, will show as a small capacitance.


This, by the way is a good way to check an SWR meter for accuracy,
providing, of course, the loads you use are pretty good as well. You can
easily do 2:1 and 4:1 (with two "T"s and four loads) if you have them.

P.s. If you needed to, and it was a good 50 ohms, you could use an antenna
for one of the loads.

73, Steve, K9DCI



This is good for things like phased yagis, but you wouldn't want to
hook an antenna to one port and a dummy to another...

Dan,
N3OX
www.n3ox.net