Larry,

Where did you measure the impedance? Probably not at the feedpoint. You
would have to use a Smith chart to determine what the actual antenna
impedance is. A 2:1 balun *at that point* should work, though. They are hard
to find. Amidon has one, but it is about $60. I have fed multiple dipoles
off the same feedpoint, and gotten an impedance close to 50 Ohms; however, I
had something like 15 degrees separation between the dipoles.

Tam/WB2TT
"Larry Gauthier (K8UT)" wrote in message
...
I just completed the installation and tuning of a multiband inverted vee
for
160, 80, and 75 meters. Essentially, the antenna consists of a center PVC
insulator with 6 terminal posts (2 per band) and the three dipoles
separated
by wooden dowel-rod spreaders at spacings of about 6 inches. All three
sets
of wires are direct fed with one RG/8u.

I have adjusted the lengths of each antenna to move the resonant point to
preferred frequencies for each band: 1.825 on 160, 3.525 on 80, and 3.775
on
75. However, at resonance the SWR on all antennas remains relatively
high --
an MFJ259 analyzer says resonant SWRs are around 1.7-2.0:1 and
characteristic impedances are 100 ohms or slightly higher. Is a 2:1 balun
the solution, and which balun method? Seems to me I have the following
choices:

1. A "balun kit" from someone like thewireman.com and build my own. This
could be in either the form of a voltage or a current type -- which type
would be best?

2. A coax balun in the form of a 1/4 wavelength of RGB/11u 75 ohm coax --
replacing a portion of the RG/8u feedline with RG/11u. But since I am
using
this for two bands... what length would offer the best compromise for both
80 and 160?

3. A coiled-coax balun which I have seen described as "about 16 turns of
RG8x on 3 inch PVC stock".

All of these options are easily do-able, but which looks like the best
route? Your opinions are welcome.
------
-larry
K8UT