simple dipole for newbie - copper, alum, or galv steel pipe?
 

"Bob" wrote in message
. ..
Ladies and gentlemen, here is a perfect example of CB mentality that has
plagued the radio hobby from the beginning. Someone here obviously doesn’t
understand the fundamental nature of antennas but preaches bogus
information as it was gospel. Maybe the half wavelength mobile antenna
with the perfect match he refers to is his fiberglass loaded CB antenna,
which is advertised in half, full, one and a half, and every combination
of silly lengths to please CBrs as the dealers take their money. They do
match ok, but are not the full length, end fed, very high impedance half
wave antenna that he originally described in this thread. If you actually
read the ARRL handbook you will see Mr. Wolf’s grievous mistakes.
Bob


Aah! A voice of reason. I well remember the CB ads re 1/2 wave and full wave
antennas. As far as I could tell, the only thing half wave was maybe the
overall length of wire if it were unwound and stretched out straight.

Dale W4OP

simple dipole for newbie - copper, alum, or galv steel pipe?
 

Wow, thank you for all of the advice everyone. Apparently I have some
more reading to do...

In the meantime I put together an off-center dipole 48" up 18" down
using aluminum wire. I understand there are probably better options,
but this provides significant improvement over what I had before.

Just one question about this antenna - how would one estimate the
impedance? I don't have an impedance analyzer. I have read in this NG
that the impedance will be roughly 300 Ohm, and that a TV-type balun
would bring it down to 75, which would be better than 300 if not
ideal. I have read elsewhere that it will be roughly 75 Ohm and no
balun is necessary. What is the truth?

I do have a 4:1 balun that would work if impedance is around 300, but
if impedance is around 75 would there be any benefit or harm in using
it?

Thank you all again,
Paul

simple dipole for newbie - copper, alum, or galv steel pipe?
 

On Wed, 20 Sep 2006 17:23:49 GMT, Paul Monaghan
wrote:

Just one question about this antenna - how would one estimate the
impedance? I don't have an impedance analyzer. I have read in this NG
that the impedance will be roughly 300 Ohm, and that a TV-type balun
would bring it down to 75, which would be better than 300 if not
ideal. I have read elsewhere that it will be roughly 75 Ohm and no
balun is necessary. What is the truth?

The truth is that a scanner that covers a wide range of frequencies
rarely shows 50 ohms, and that's only over a very narrow frequency
range, so I wouldn't worry about it. Putting on a balun may improve
reception on some frequencies, only to degrade it on others.