rf induced fire in the trees?
 

hi. i'm about to be a new ham. i hv only 1 chance for an antenna for
80m (or 40, even 20). there's a 120' oak tree in the yard with 70'
clear on either side. so i thought a ladder-line center-fed inverted
vee dipole (63' per leg, 14ga teflon insulated stranded) would be my
best bet...so at 100W, even 600W ...am i going to set the tree on
fire? any ideas on how to keep bad things from happening? thank you
very much?

jimg
jimg
Oregon
USA

rf induced fire in the trees?
 

VERY unlikely you will set the tree on fire...you would have to be
running several kw at the very least to even begin to start a fire!

Steve



On Sun, 06 Nov 2005 10:02:10 GMT, jimg wrote:

hi. i'm about to be a new ham. i hv only 1 chance for an antenna for
80m (or 40, even 20). there's a 120' oak tree in the yard with 70'
clear on either side. so i thought a ladder-line center-fed inverted
vee dipole (63' per leg, 14ga teflon insulated stranded) would be my
best bet...so at 100W, even 600W ...am i going to set the tree on
fire? any ideas on how to keep bad things from happening? thank you
very much?

jimg
jimg
Oregon
USA

rf induced fire in the trees?
 

Steven Fritts wrote:

VERY unlikely you will set the tree on fire...you would have to be
running several kw at the very least to even begin to start a fire!

Steve

On Sun, 06 Nov 2005 10:02:10 GMT, jimg wrote:

hi. i'm about to be a new ham. i hv only 1 chance for an antenna for
80m (or 40, even 20). there's a 120' oak tree in the yard with 70'
clear on either side. so i thought a ladder-line center-fed inverted
vee dipole (63' per leg, 14ga teflon insulated stranded) would be my
best bet...so at 100W, even 600W ...am i going to set the tree on
fire? any ideas on how to keep bad things from happening? thank you
very much?

jimg
jimg
Oregon
USA

As long as the outer ends of the Vee are out of the branches you will be OK.

Irv VE6BP
--
--------------------------------------
Diagnosed Type II Diabetes March 5 2001
Beating it with diet and exercise!
297/215/210 (to be revised lower)
58"/43"(!)/44" (already lower too!)
--------------------------------------
Visit my HomePage at http://members.shaw.ca/finkirv/index.html
Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/index.htm
Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/index.htm
--------------------
Irv Finkleman,
Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP
Calgary, Alberta, Canada

rf induced fire in the trees?
 

hi. i'm about to be a new ham. i hv only 1 chance for an antenna for
80m (or 40, even 20). there's a 120' oak tree in the yard with 70'
clear on either side. so i thought a ladder-line center-fed inverted
vee dipole (63' per leg, 14ga teflon insulated stranded) would be my
best bet...so at 100W, even 600W ...am i going to set the tree on
fire? any ideas on how to keep bad things from happening? thank you
very much?


My own opinion, I do not like Oak trees for antenna work.... when the
leaves are on, they are difficult, to say the least. However, with
winter here, I'm sure you will be able to configure the apex of your
inverted V OK in that big tree.

Have you actually considered the amount of real estate you need for
an Invertet V for 75M ? With a center height of only 40 feet, your 1/4
wave legs will extend out barely over about 47 feet each side of center.
You may be able to do what you are thinking with a simple center mast
instead of using the Oak tree. It certainly would make working on your
antenna and changing things a bit easier.

Good luck, either case.

Ed K7AAT

in Oregon, too.

rf induced fire in the trees?
 

Irv Finkleman wrote:
As long as the outer ends of the Vee are out of the branches you will be OK.

That works for 80m but what about 40m where the voltage maximum
point is at the feedpoint?
--
73, Cecil http://www.qsl.net/w5dxp

rf induced fire in the trees?
 

On Sun, 06 Nov 2005 10:02:10 GMT, jimg wrote:

hi. i'm about to be a new ham. i hv only 1 chance for an antenna for
80m (or 40, even 20). there's a 120' oak tree in the yard with 70'
clear on either side. so i thought a ladder-line center-fed inverted
vee dipole (63' per leg, 14ga teflon insulated stranded) would be my
best bet...so at 100W, even 600W ...am i going to set the tree on
fire? any ideas on how to keep bad things from happening? thank you
very much?

jimg
jimg
Oregon
USA

I have an 80 meter dipole running through three trees; I use a
standard tree trimmer (reach about 20'-25') to keep the wires pretty
much in the clear.

bob
k5qwg