[AMRadio] Valiant and Loop progress


Brett gazdzinski Brett.gazdzinski at mci.com
Tue Dec 6 09:41:01 EST 2005


Yes, I know I want something impossible, given the space and supports I have
to work with.
The best solution would be a higher support in the center, but a tower
is out, due to cost, looks, and maybe zoning.
I would be able to get away with some sort of 60 foot mast, its only
going to hold the center of the antennas up, but I have not seen anything
like a 60 foot mast. Radio shack does not even sell the 
36 foot telescoping mast anymore.

I have looked in many books for antenna ideas, but given what space
and supports I have to work with, I have not seen anything that would do 
what I want at the power levels I can get to.

The 40 meter antenna works great, and I suppose I don't need to do anything
with it, but fitting an 80 meter antenna in the space, without it being
right
over the house is the problem.

The bigger trees in the front of the house are close to the house, not out 
by the street, which limits the length.

I have the 2kw heathkit antenna tuner (I built it) with the meters built in.
On coax, it always worked ok as long as the high voltage point was away from
it.
Peak power on the 813 rig can get well over 2500 watts, past what the
heathkit
was designed for.

The built in balun was very small, and I never had it work well, but that
may 
not be its fault, maybe it was always at a high voltage point....

Maybe the best solution is to try to put up some sort of 80 meter antenna
parallel to the 40 meter dipole, using another tree out front.
I could run some open wire line to it, or coax, or some mixture of both,
and put it into the tuner, or make a balanced tuner.
That would put it at right angles to the house, and maybe cut the rf into
everything.

I will have to look at the trees, and think about it...

Thanks for all the tips, I will look at each and see if there is any way
to try them.

Brett
............................................................................
..

Keep on with thie list of things you don't want, or won't put up with, 
and you'll force yourself to you only solution ;-)

Move the pole on the side of the house, to the middle of the back of the 
house.  Use whatever methods to extend the top of this mast to 60'.  
Twist the pole until it's in the ground a good foot or so, secure this 
pole to the eave of the house, then from about another 10' up from the 
eave, secure the pole with UV resistant rope, to both sides of the house 
and Secure the ropes the eave of the house,  Use the pole to support the 
apex of a pair of dipoles.  the 75m dipole should run from the Cedar 
Tree, across the top of the house, out towards the street.  Put the 40m 
dipole on the same pole, fed with a different run of coax, but run the 
40m dipole at 90 degree angles to the existing 75m dipole.  Use some 
more of the UV resistant rope and tie one end to the center insulators, 
and run it through a pulley, so you can work on the dipole with having 
to climb up the pole.

That's one way.

In my case, I had the same concerns about RF in the shack... I put 
thetuner on a shelf near the wall where the coax comes in - there's 
*maybe* 6 ~ 8" of ladderline in the shack.  The Heathkit tuner is 
grounded. I don't know which Heathkit tuner you've had, but I've pumped 
1,500 watts of CARRIER into this one (after it was tuned for minimum 
SWR) into a dumy load and Modulated it.  I'm still using the tuner.  If 
you ddin't build it, then I'd say that the balun wasn't crappy, rather 
that the builder's technique might have been nothing to be desired.

73
-Geoff/W5OMR


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