Topband: Effect of trees- tree appreciation

[Tom W8JI]

> Where are the high voltage points in a "T" antenna?

The highest voltage is generally at the open end, but how high that voltage 
is depends on the boundary area between the antenna and whatever is around 
the antenna.

The slippery slope here is that people might think only the very ends have 
high potential or might add significant loss, and that distance is the only 
factor. Loss is a complex issue. Just as current density and resistivity in 
a given volume are determining losses, so is the area and media the field is 
distributed over.

The point is, moving an end away at the expense of an overall increase in 
area exposed to a lesser "voltage" might not be a good solution.

> I have the choice of putting up either a new T between two trees, or an L 
> again on 160M. The ends of the T would by necessity be strung over and go 
> down 20-30' alongside the two supporting trees.
>
> The L would parallel a tree and bend over at around 75-80'. The horizontal 
> end of the L would end up 20-30' from its tree support. I'd reuse my 8 
> tuned elevated radials, plus maybe a couple more.
>

This is a good example where the problem of not quantifying things comes in. 
No one here knows what the typical loss or interation is, and it is probably 
impossible to know what the extact interation is in every situation. I think 
interaction is modest unless the conductor is right in the foliage. Based on 
one element I had with one large pecan tree, it was a 130 ft element 
probably 40-60 feet from the trunk, I saw maybe ten percent increase in base 
resistance. That tree was probably 60-80 feet tall, so it was nowhere near 
the open end. The branch tips from that tree were within 10-15 feet of areas 
of that antenna.

I don't think anyone can answer any questions about this with more than a 
guess. The T might might be better, worse, or the same. My gut feeling is 
the one that looks the best and takes the most work will make you feel like 
you have the best signal you ever had, but no one else will notice the 
change except you unless you tell them about all the work or they "like" a 
particular antenna you are using.

73 Tom