Very nice study and IMO neither small nor inelegant. Thanks
From: Roger Parsons ve...@yahoo.com
To: Topband topband@contesting.com
Sent: Friday, August 9, 2013 7:29 AM
Subject: Re: Topband: Tree losses
I just did a small and inelegant piece of modelling with EZNEC.
I took a wire 128
I just did a small and inelegant piece of modelling with EZNEC.
I took a wire 128' vertical, and it showed a gain of about 1.7dBi over a
particular ground.
Keeping everything else the same, I introduced a 'tree' 3ft away from it, with
no branches, exactly parallel, also 128' high and
As Tom, Rudy, and Richard have noted, this stuff is potentially
important, but awfully difficult to quantify for a variety of reasons.
One is that what's happening in the trees is not the only thing that is
happening when the seasons change. Out here along the Pacific coast, we
have a rainy
Well Tom, you surprise me since I thought in the past you were one of
those
who felt tree losses were minimal and part of mythology for HF/MF. I
guess you changed your mind now that others have shown different.
I think they are minimal, if the tree is not right next to the antenna. I
never
Gentlemen:
I wanted to weigh-in on the discussion of the impact of tree losses on
transmitting antenna performance. Of course I have no quantitative
data, but experience is suggestive of potentially significant losses.
I used to live in Grayson County, Virginia, on a completely wooded
hilltop.
The only way to say which location is better is to do a side by side
comparison which didn't happen. You are making assumptions which may be
wrong or may be right. Blaming it on trees is a guess. There are many
other factors to consider.
Doug
-Original Message-
It's hard to quantify
Hi Doug ,
Like so many things related to antenna installations, side by side
comparisons are usually impossible. Without the ability to do meaningful
measurements, it is also unlikely that one can capture all the unknowns
that can add up to a large effect. I could do only relative field strength
Severns rseve...@gmail.com
To: Topband topband@contesting.com
Sent: Sunday, August 04, 2013 5:39 PM
Subject: Topband: tree losses
Tom's correct, the issue is not resonance but rather what, if anything,
happens when you have a so-so conductor/insulator (a tree) in the
near-field and/or further
Rudy Severns wrote:
Tom's correct, the issue is not resonance but rather what, if anything,
happens when you have a so-so conductor/insulator (a tree) in the
near-field and/or further out. Do the losses matter?
Here are several data points on this subject.
Recording the
: Topband: tree losses
Tom's correct, the issue is not resonance but rather what, if
anything,
happens when you have a so-so conductor/insulator (a tree) in the
near-field and/or further out. Do the losses matter?
Performing a definitive set of experiments would be a serious
undertaking. I've
Bruce-K1FZ
- Original Message -
From: jim rogers jd...@bellsouth.net
To: ZR z...@jeremy.mv.com
Cc: Topband topband@contesting.com; Rudy Severns rseve...@gmail.com
Sent: Monday, August 05, 2013 6:03 AM
Subject: Re: Topband: tree losses
Carl et al,
Interesting, my 80M full size (66
I hope all of us can keep the topic at least somewhat scientific, logical,
or rational, and less subjective, blind faith, or outright
off-the-wall..
Tom's correct, the issue is not resonance but rather what, if anything,
happens when you have a so-so conductor/insulator (a tree) in
I found this and at least it makes a good old read.
http://www.rexresearch.com/squier/squier.htm
regards,
Raoul ZS1REC
From: Tom W8JI w...@w8ji.com
To: Topband topband@contesting.com
Sent: Monday, August 5, 2013 4:53 PM
Subject: Re: Topband: tree losses
Bingo! Just because the military does (or did) something with antennas
doesn't means it's good for us all to repeat.
There was a discussion some time back that a Beverage must make a good
transmitting antenna, because the military does it somewhere. I can vouch
for the fact that while we can
I found this and at least it makes a good old read.
http://www.rexresearch.com/squier/squier.htm
This is how things get started! once something is in print, no matter how
wrong or unsubstantiated, it lives forever. Look at this statement:
It will puzzle the amateur as it has puzzled the
: Topband: tree losses
Bingo! Just because the military does (or did) something with antennas
doesn't means it's good for us all to repeat.
There was a discussion some time back that a Beverage must make a good
transmitting antenna, because the military does it somewhere. I can vouch
for the fact
and to improve jam resistance and signal to noise ratio.
73
Frank
W3LPL
- Original Message -
From: Mike Waters mikew...@gmail.com
To: Tom W8JI w...@w8ji.com, topband topband@contesting.com
Sent: Monday, August 5, 2013 7:04:16 PM
Subject: Re: Topband: tree losses
Bingo! Just because
That's what we need, real data. Expand the experiment and see what we can
learn.
While I feel that our data on the subject is pretty thin and I'm not about
to
make any pronouncements I'm still quite happy that at my new QTH the trees
are many hundreds of feet away. I would also go out of
- Original Message -
From: jim rogers jd...@bellsouth.net
To: ZR z...@jeremy.mv.com
Cc: Topband topband@contesting.com; Rudy Severns rseve...@gmail.com
Sent: Monday, August 05, 2013 9:03 AM
Subject: Re: Topband: tree losses
Carl et al,
Interesting, my 80M full size (66') sloper comes
Jim, it seems to be a difficult subject for those who want to make a huge
case out of taking measurements as if this was a scientific undertaking
requiring a decade of reviews, papers, and the usual academia way of
wasting time.
Carl,
There isn't any reason to turn everything into something
Hi,
For me the effect the trees have is purely academic. I live in the
northern Michigan forests. I am surrounded and even protected by the
trees. My antennas are *in* the trees. I'm sure the trees have some
effect. There is nothing I can do but operate anyway. If the tree
studies find that
Bingo! Just because the military does (or did) something with antennas
doesn't means it's good for us all to repeat.
While Beverage antennas for transmitting are indeed one example, two more
good examples are:
1.) that silly Maxcom antenna tuner sold from Florida, the thing that had
the
Tom and all,
After spending 25 years in the military (Navy specifically), I can say, with a
fair amount of authority, that the antennas used by them are often used for
much different purposes than what people on this forum use them for. he he
he. Never would a scenario arise where 1.8mhz
On Mon, Aug 5, 2013 at 2:54 PM, ZR z...@jeremy.mv.com wrote:
Youre unfairly throwing a huge spin on it Mike.
Am I? Okay. Sorry. :-)
If the military or a government agency does it, it could be an experiment
or a purpose built project where the alternatives werent adequate or too
Tom's correct, the issue is not resonance but rather what, if anything,
happens when you have a so-so conductor/insulator (a tree) in the near-field
and/or further out. Do the losses matter?
Performing a definitive set of experiments would be a serious undertaking.
I've fiddled around a bit
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