> Having at last found time to study the recent, and most interesting,
> "Two
> Wire Beverage thread" I cannot find the answer to one particularly
> interesting question:
> How close should one put the wires in a two wire Beverage system?
Hi Hermod,
Closer is better if you can keep the wire spacing very uniform.
Closer spacing for a given wire size will lower the impedance
of your open wire transmission line (2-wire Beverage).
The further the wires are apart, the higher the impedance will be (up to
a point). The higher the impedance the more difficult it will be
to match and keep electrically balanced. More inductance is needed in
the transformers and that may yield higher losses.
I have read some "guide lines" on the maximum spacing,
in terms of wavelength (operating frequency)....I don't recall
what they are, but I do recall that 6" spacing on 10 meters
is too much.
If you are making your own line, use a spacing of not more than
around 6"and use "large" wire to bring the impedance down to
less than say, 600 ohms.
A line of #12 copper wire spaced 6" will make a line ~600 ohms. A line
of ~450 ohms uses #8 with a spacing of ~2.75" inches. See the
older ARRL handbooks or ARRL antenna books ("Line contruction
and operating characteristics") for details on making/spacing/insulating
your own line.
Hope that helps.
73,
Charlie
N0TT
________________________________________________________________
The best thing to hit the Internet in years - Juno SpeedBand!
Surf the Web up to FIVE TIMES FASTER!
Only $14.95/ month - visit www.juno.com to sign up today!
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|