Subj : Antenna
To : BEN RITCHEY
From : Thom LaCosta
Date : Tue Jul 05 2005 07:43 am
BEN RITCHEY wrote in a message to ALL:
BR> I have a weather radio that get's poor reception so I'd like to
BR> extend and/or complement the telescopic indoor antenna with an
BR> external antenna. I have a 17 foot piece of insulated #12 copper
BR> wire I'd like to use. 1st question; does it need to be bare wire?
Shouldn't make any difference whether or not the wire is naked(other than
if some wire prude catches you).
BR> The entire length? By the time I feed outside, that's about 2 feet
BR> horizontal. Another 4.5 feet vertical to the eaves where I can turn
BR> and go horizontal for another "x" feet, up to 20 feet. Full
BR> wavelength for a frequency of 162.5 MHz is exactly 6 feet
BR> (remainder less than an inch), so how long should I make "x" above?
BR> I cannot extend the vertical portion longer than 4.5 feet ...
The internal circuits of the radio may be such that it doesn't expect a full
wave length antenna....and by using that, you could have a rather large
impedence mis-match.
Some folks have used a "long wire" and coupled it loosely to the receiver using
a coil that resonates at the frequency of interest....you could try
wrapping a few turns of the insulated antenna wire around the rod antenna.
Another factor to consider is the polarization of the transmitted signal. Most
of VHF stuff is vertical....your sky catcher has a decent amount of
vertical capture.
If it were me...I'd play not only with the loose coupling, but also the
orientation of the wire....and at the same time look around for a vhf
pre-amp....
Good luck!
cya,
thom
http://www.tlchost.net/echolist/
--- GEcho 1.20/Pro
* Origin: Home of The Other Robot (1:261/1352)
