Topband: Effects of trees

[Tom Rauch]

> Do I understand it correctly that it's far, far better 
> situation to have a
> GROUNDED STEEL TOWER in the immediate proximity of a 
> radiating vertical
> antenna, rather than a LOSSY TREE...?

The power or energy either turns to heat through a 
resistance or it goes somewhere that might be useful.

A tower could be bad news if the base of the tower was not 
properly ground to a good ground system. With the base of 
the tower stuck in the dirt, there might be enough current 
conveyed to the lossy dirt to turn RF into heat. It can 
always be detuned. It can always be grounded to a good 
ground system. It can always be fixed.

A tree is whatever it is. It can't be detuned. It can't be 
grounded. Any effect it has I have no idea how the trees 
near one of the 1/4 wave vertical elements of my four square 
affected the efficiency or the pattern. My antenna seemed to 
work fine despite that one element being out of whack.  All 
I know is the base impedance was higher when the trees were 
there, and dropped quite a bit when I had the trees removed.

The trees never stopped me from using the antenna, I never 
even worried enough to cut the trees cut down. I just always 
thought the trees might have been the reason I could never 
get the impedance of that element down, and when the trees 
were removed and the impedance dropped now I know the trees 
affected the antenna in some way.

This didn't stop me from using that antenna, and I still 
don't know if it affected efficiency any amount. But then I 
can't tell the difference between running 500 watts and 1500 
watts, or using a dipole I know is 5dB weaker. I still make 
contacts.

It's always nice to know how to squeeze the last fraction of 
a dB from a system, but the fact is no one would ever notice 
3dB (let alone lesser amounts) most of the time. We 
certainly can't tell an hour later, let alone a week or year 
later, if an antenna is working better or worse.

Do I think trees impact the antenna in a negative manner? 
Sure I do. So do many other things. How much is anyone's 
guess, but any amount it hurts is certainly meaningless when 
compared to not having any antenna at all.

73 Tom