ICOM AT-150 tuner antenna ports
- From: KC0JBJ <KC0JBJ.25eeyu@xxxxxxxxxxxxxxxxxxxx>
- Date: Tue, 28 Mar 2006 18:17:46 +0000
I just bought an ICOM AT-150 antenna tuner to go with my ICOM IC-735
(still looking for that elusive object, a moderately priced PS-55
matching power supply in good condition!).
The tuner has four antenna \"ports\" on the back. #1,2,and 3 all have
SO-239 connectors and are clearly for 50 ohm balance line
antennas/feedlines. The fourth port is simply a push-insert-release
wire terminal. The manual states that this port may be used for
attaching a long-wire antenna for general coverage reception. However,
it also states that all 4 ports may be used for transmitting, as long
as the SWR is already 3 to 1 or below.
Now I am curious, if this port is for a long-wire antenna (a balanced
load, if the unit is well grounded, right?), does that mean there must
be a balun inside the box, and does it have some ratio other than 1:1
(i.e. 4:1, 6:1) if it is to match the 50 ohm input to a high impedance
output like a long-wire. Or am I confusing the terms \"long-wire\" and
\"random-wire\". Would a \"long-wire\" antenna be a balanced load if it is
resonant on some band?
I really would like to know what kind of antenna and/or feedline I
could use on this single-wire port for transmitting. Is there a 50 ohm
ladder-line that would be a match if I connect the other wire to the
ground? Please help!