[PCR-1000] Antenna Height

[rr]

If your talking VHF or UHF your discone does not have to be high because 
VHF and UHF signals are line of sight mostly. The only reason you elevate 
the discone is to be clear of metal obstacles. Metal near ANY antenna will 
affect the reception and almost always negatively.  Thats why the discone 
just laying on the couch only sounds marginal better up higher.
I have mine hanging from a tree limb 30 feet up to have it clear the shadow 
of the house.
Discones do not have much or any gain.  .
If you are interested in long distant reception in you need a vertical or a 
yagi antenna to pick up those distant signals.  Both vertical and Yagi 
antennas have gain.... each Db of gain increases the signal 10 times.
Thats why a discone which does not have any gain at 70 feet is as good as 
one at 20 feet.  Even though it is up much higher and should see farther 
the signals from far away are too weak to be picked up by the 
discone.  This is not true for a vertical or yagi antenna.

Now on HF higher is always better because the signals bounce between the 
earth and the ionosphere... so when you put it up higher
you get more signal.  Also if you use a long wire antenna, reception is 
always improved by using an antenna tuner.

Antennas are like flutes they have to be the right length in order to 
resonate (amplify) the frequency of the signal you are interested in.
Otherwise you will not pick up a lot of signals that are there if it is not 
intune with what you are listening to...

To calculate how long an antenna needs to be...  take 300 and divide the 
frequency you are interested into it. This will give you the answer in 
meters...  and example 144mhz into 300 yields around 2 meters.  So the 
higher the frequency the shorter that antenna.
Seeing the cell phones operate in the 800mhz range that makes the antennas 
needed very short.  Antennas can be a harmonic of the fundamental 
frequency..  they can be 1/2 wave 1/4 wave or 5/8 wave.  The above formula 
gives the answer in full wave length.

There is no ONE antenna that picks up everything. Invest or make a switch 
box to switch between antenna's. Seeing you are only using the antenna to 
receive an not transmit, regular small switches can do.

Here's a link on propagation
http://www.arrl.org/tis/info/propagation.html

use the arrl.org site to learn more about antenna's and such....

I think antennas are one of the fun things about radios... for $20 USD all 
you need is wire and insulators and sturdy string and some trees and you 
got the ability to pickup SW stations 10,000 miles away...  When I put up 
my second long wire up at 70 feet in a tree - I picked up Turkey the first 
time ever from Florida...  on long wire the direction of the signal is the 
direction the wire is strung.

Robert Rathbone
KG4WKM
Florida