At my summer QTH, I cannot do more than using a "stealth" thin-wire =
antenna.

For operation 40 through 10 meters, I had fairly good results using a =
plain 30-ft wire and a tuner. But I do not like that solution because, =
in my case, access to earth (water pipe) is not convenient.

So, I decided to switch to a symmetrical antenna that does not require =
an earth connection. I have then mounted a square wire loop, about 15 ft =
each side, fed with about 5 feet of 450-ohm ladder line. The antenna =
impedance varies a lot across the desired frequency range, but it can be =
easily matched by my tuner on all bands.

The antenna being symmetrical, and the tuner asymmetrical, it is =
advisable to use a balun. Three solutions come to my mind:
=20
1) using an off-the-shelf (e.g. MFJ, Vectronics, etc.) toroidal ferrite =
balun at the tuner output. I do not like this solution because, on some =
frequency bands, the antenna impedance gets very high, and I am not sure =
on how the RF transformer behaves under those conditions

2) putting an RF choke at the tuner output. The choke could be built by =
winding several turns of 450 ohm ladder line over a fat ferrite rod =
(obtained by glueing several small rods to each other)

3) putting an RF choke at the tuner INPUT, by winding several turns of =
the RG-58 cable connecting the transceiver to the tuner on a ferrite =
rod. In this way the tuner body would be "hot", but this may not be a =
real problem

Any comment on the pros and cons of the three approaches would be =
welcome.

73

Tony, I0JX