Mike,

Due to limited space in the roof - I'm renting so won't risk an external
antenna - my setup is similar to this. I use an OCF dipole (some call it
a Windom but this is incorrect) with a 300 ohm feedline running to a
wallplate in the loungeroom. From there it goes to a 4:1 TV-style balun
and into 75 ohm coax. Works quite well. The dipole is in parallel with
an existing VHF TV antenna, so it should do well at 20 meters too when I
finally decide to play up there.

Not sure about your earthing situation, mine didn't need it. The setup
looks like this. I'm in Australia if you're worried about the weird
orientation:


^
\
North

__________________( )_____________
| 10M H 5M |
| H |
| 4M H 3M |
| H |
| H
H
El-Cheapo H
4:1 Balun H 300 ohm
{X}=========== ribbon feedline
|
| 75 ohm
| Coax
|
[SDR-1000]

Rob


mike wrote:

Given I am currently using 75 ohm coax to feed my random wire, I
believe I could use a 300 ohm to 75 ohm (4:1) TV twin lead to coax
converter and get away with it.

Please correct me if I am wrong, but I think I would attach the random
wire to one terminal of the 300 ohm input. The other would go directly
to earth ground, or via a gas arc tube to ground.

On the other side, I would attach my coax cable.

To give the coax feeder a ground at the antenna end, I would to open
up the converter and solder in a ground wire on the coax sheild
terminal. This would kill off common mode currents.

This would give my antenna feeder system a matching transformer plus
give the antenna a direct path to ground.

Theoretically, I am I missing anything?

mike