View Single Post
  #3   Report Post  
Old January 25th 04, 01:05 AM
Maximus
 
Posts: n/a
Default

If I had property big enough, I'd have a horizontal antenna running
north-south and another east west. I'd have them connected to a switch and
they would be as long as space permitted, and as high as I could get them.

Lots of people use an antenna sloping at an angle from high to low as long
as at least a 1/2 wavelength of the middle frequency of the band in
question.

Another good antenna is a "V" shaped antenna supported from the middle such
that the length can be as near to 1/2 wavelength of the center frequency of
the band of interest.

However, if a coat hanger gets you the desired reception, then you are home
free s. I don't mean to ridicule ! For receiving, length is not critical -
it IS if you are transmitting, and it becomes very important in relation to
the power output of your transmitter - meaning if there is a significant
mismatch, you can kiss off your radio g.

A wire suspended in space has a specific length. That length can be equated
to the distance between the crests of waves that defines a particular
frequency. If you want to listen to 60 meters 3.28 ft x 60=1968 feet for a
full wavelength. A receiving antenna can be as short as 1/4 of that length
and still present efficient reception of a signal in the 60 meter band,
especially if recieving conditions are good and the broadcaster is using
200,000 watts or more. At the same time, if you have a good receiver and a
good antenna and good conditions, you can have five or six good signals all
arriving at the antenna at the same time. Some signals may be lightening
crashes, or unwanted signals, such as noise from your refer or the
neighbor's computer or car ignition. You have no conrol over that, and the
longer the antenna, the more energy imparted to the wire, and thus the
reciever. You cannot control that, but if you are fortunate enough to have
some audio processing equipment included in your equipment, you might be
able to minimise te unwated sounds.

My antenna is not just one wire. I am fortuante to have an understanding
property manager, and I have three wires of at least 80 feet between my
apartment and a convenient tree running approximately north-south. I also
have a wire slung up into a fir tree up to at least 80'. The 3 wires are
connected together and connect to coaxial cable to the center connector, The
other wire slung up into the fir tree, is connected to the braid of my
coax. the receiver is grounded to an earth ground. There is a cell tower in
the area, and someone has a constant computer signal, and I get hit on
various frequencies. I still listen S. Any length of wire at least 30 feet
to 75 feet in length will make a good antenna. But to be completely
scientific and get the optimum response, calculate the frequency at the
center of the band of most interest, and put up an antenna at least 1/4 of
the wavelength. I always use INSULATED wire. That protects the wire and
protects you from unfortuante accidents involving contact with power lines -
not a good scenario .
"J999w" wrote in message
...
I'd go with the random wire, unless you either have a favorite band to cut

the
dipole for (49 meters perhaps), or can feed the dipole with twin lead.

jw
wb9uai