|[AMRadio] Stealth Antennas?|
ka1kaq at gmail.com
Mon Jan 24 16:08:00 EST 2005
<macklinbob at msn.com> wrote:
> I live in a senior apartment where I CANNOT have an outdoor antenna. So I
> have a wire around the wall at the base of the ceiling. It is currently 1/4W
> 40M antenna.
> I did buy the ARRL book on "Stealh Radio".
> HF mobile antennas use loading coils to make the antenna look longer. The
> better one us a coil in the center of the antenna.
> Some apartment antennas are nothing but a mobile whip with a base loading
> coil. Why BASE LOADING?
Old habits die hard? I suspect it's an issue of weight and keeping the
whip as vertical as possible, but I won't swear to it. I have seen
center-loaded mobile antenna arrangments, and even some like the Texas
Bug Catcher with a large coil and capacitance hat nearer the top.
They're usually tied up or otherwise supported as a result.
Base loading would be more stable in a mobile arrangement and since
it's just a coil of wire to make the radiator electrically longer and
not actually strung out as a vertical radiator, it's not as critical.
Sounds like you have the perfect opportunity to do some experimenting
with different arrangements, hopefully the neighbors won't hear you on
their Chinese appliances.
Trap dipoles work on a similar principal, with the traps positioned
according to the lengths of wire used as radiators. Seems like you
could use this arrangement to improve your situation, depending on the
power levels used, of course.
Good luck with it, let us know what works best.
de Todd/'Boomer' KA1KAQ
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