....and I'm gonna use existing trees to put it up about 30 feet above
ground, 15 feet above my rooftop on a 5x100 foot suburban lot. Power
lines both in front and back of my house, the ones behind are much
higher voltage, but not real high-tension wires.

All other things being equal, am I better off:

1 - Putting this thing up parallel to, or more perpendicular to, the
powerlines?

2 - Having the coax meet the wire at the base of the tree and
grounding it there, or running the coax up the tree and then depending
on the outer braid on the coax for ground purposes? The coax is
grounded at the first termination point at my MFJ antenna phasing unit
using a short, heavy copper wire to a ground rod.

Thanks,
Bruce

On 5/20/10 12:32 , bpnjensen wrote:
...and I'm gonna use existing trees to put it up about 30 feet above
ground, 15 feet above my rooftop on a 5x100 foot suburban lot. Power
lines both in front and back of my house, the ones behind are much
higher voltage, but not real high-tension wires.

All other things being equal, am I better off:

1 - Putting this thing up parallel to, or more perpendicular to, the
powerlines?




That's going to depend on what's on them. As a rule, minimum
coupling would occur with a perpendicular arrangement in the same
plane.

That said, the lines out of Bagnell Dam picked up and carried WLS
and KMOX deep into the Ozarks with a city grade signal. To recover
those, I oriented my antenna parallel to the power lines.

You may have to experiment.


2 - Having the coax meet the wire at the base of the tree and
grounding it there, or running the coax up the tree and then depending
on the outer braid on the coax for ground purposes? The coax is
grounded at the first termination point at my MFJ antenna phasing unit
using a short, heavy copper wire to a ground rod.

Run the wire where you want it to be, terminate the end with a
9:1, ground the wire side there. Run the coax to the secondary of
the 9:1 and ground the coax at each end with an earth ground.

bpnjensen wrote:
...and I'm gonna use existing trees to put it up about 30 feet above
ground, 15 feet above my rooftop on a 5x100 foot suburban lot. Power
lines both in front and back of my house, the ones behind are much
higher voltage, but not real high-tension wires.

All other things being equal, am I better off:

1 - Putting this thing up parallel to, or more perpendicular to, the
powerlines?



A purely horizontal antenna will usually pick up less local noise.
But on the lower bands (say, 6 MHz and below), a low horizontal
antenna will also tend to disfavor stations over 1,000 miles distant
and favor closer (higher-angle) ones.

Generally, perpendicular to the noise source is better. Visualize it
this way: Imagine you are standing with your eyes precisely at the
noise source location. Look at your antenna. If your antenna looks
like a single point (as it would if you were looking directly at the
end of it), there will be relatively little energy induced in the
wire. With a diffuse noise source like a power line, of course, it's
not quite so simple. But even the most diffuse noise source has a
virtual source at each particular frequency, and the concept is
still helpful. Desired signals off the ends are also attenuated.

An end-fed, coax-fed single wire with its feedpoint in the air will
definitely pick up signals on the outside of the coax and act more
like an inverted L, though, and just choking off the currents with a
balun won't help much. For true horizontal polarization, you'd be
better off with a center-fed dipole arrangement, with a balun at the
center not necessary but helpful in minimizing feedline antenna
effects. See

http://www.ehow.com/how_6002278_buil...ntenna-hf.html

and

http://tinyurl.com/2ch7gzw




2 - Having the coax meet the wire at the base of the tree and
grounding it there, or running the coax up the tree and then depending
on the outer braid on the coax for ground purposes? The coax is
grounded at the first termination point at my MFJ antenna phasing unit
using a short, heavy copper wire to a ground rod.

Thanks,
Bruce



An inverted L fed against ground (which is what you're describing as
your second option) is an excellent antenna in my experience, though
it may, like a vertical, pick up more local noise than a properly
balanced horizontal.

An inverted L is virtually omnidirectional over the lower half of
its range, partly due to the fact that it has a combination of
vertical and horizontal polarization. Feeding it with coax at the
base, with a radial or a few radials laying on the earth for a
ground system (the grass roots will ensnare and cover them in a
month or two), it will receive very well on any frequency from half
up to ten times its quarter wave resonance (quarter wave resonance
in MHz is 234 divided by total wire length in feet).

Any antenna that must operate over a wide range of frequencies will
necessarily be mismatched to the coaxial cable's input impedance on
many of them. A tunable matching network will help signal transfer
-- but for lower-band receiving purposes may not really be necessary
because atmospheric noise level is usually the limiting factor.

(Antennas used over a wide frequency range also tend to have complex
patterns, with many nulls in them, once you get into the higher
frequency ranges -- say, more than twice the resonant frequency.)

Here's a simple diagram of an inverted L:

http://www.ly4a.com/hamradio-news/20...enna-for-160m/

Because of potential static buildup from wind and weather, it's good
to make sure that there's a DC path to ground from the antenna --
your receiver may already provide such a path or it can be provided
by an input transformer or a high-value resistor.

Here's another simple inverted L reference:

http://www.bloomington.in.us/~wh2t/invertedl.html

When I put up my first inverted-L antenna (60 feet in the vertical
section and 90 feet in the horizontal section) I was astounded at
how well it worked, both on HF and on the AM broadcast band. From
Hillsboro, West Virginia I was able to receive WLS, Chicago (some
500 miles away) and similarly distant stations via daytime ground
wave with perfect clarity. On 75 meters, European stations could
usually hear me well and I didn't sacrifice short-distance coverage
of the U.S. east coast.

Antennas are a heady combination of craftsmanship, instinct,
intuition, and science. I recommend the _ARRL Antenna Book_ as a
good starting point if you want to learn more.


With all good wishes,



Kevin, WB4AIO.
--
http://kevinalfredstrom.com/

On May 20, 10:32*am, bpnjensen wrote:
...and I'm gonna use existing trees to put it up about 30 feet above
ground, 15 feet above my rooftop on a 5x100 foot suburban lot. *Power
lines both in front and back of my house, the ones behind are much
higher voltage, but not real high-tension wires.

All other things being equal, am I better off:

1 - Putting this thing up parallel to, or more perpendicular to, the
powerlines?

2 - Having the coax meet the wire at the base of the tree and
grounding it there, or running the coax up the tree and then depending
on the outer braid on the coax for ground purposes? *The coax is
grounded at the first termination point at my MFJ antenna phasing unit
using a short, heavy copper wire to a ground rod.

Thanks,
Bruce

Gentlemen, Peter and Kevin, thank you for the excellent ideas - some I
knew, some ARE new - I don't have a lot of room to experiment, but my
trees are situated so as to allow a generally perpendicular
orientation to the power lines, my main nemesis. Unfortunately, 30
feet is about as high as I can practically put them, but it's higher
than what I have now, so anything is an improvement, eh? Again,
thanks :-)

bpnjensen wrote:
On May 20, 10:32 am, bpnjensen wrote:
...and I'm gonna use existing trees to put it up about 30 feet above
ground, 15 feet above my rooftop on a 5x100 foot suburban lot. Power
lines both in front and back of my house, the ones behind are much
higher voltage, but not real high-tension wires.

All other things being equal, am I better off:

1 - Putting this thing up parallel to, or more perpendicular to, the
powerlines?

2 - Having the coax meet the wire at the base of the tree and
grounding it there, or running the coax up the tree and then depending
on the outer braid on the coax for ground purposes? The coax is
grounded at the first termination point at my MFJ antenna phasing unit
using a short, heavy copper wire to a ground rod.

Thanks,
Bruce

Gentlemen, Peter and Kevin, thank you for the excellent ideas - some I
knew, some ARE new - I don't have a lot of room to experiment, but my
trees are situated so as to allow a generally perpendicular
orientation to the power lines, my main nemesis. Unfortunately, 30
feet is about as high as I can practically put them, but it's higher
than what I have now, so anything is an improvement, eh? Again,
thanks :-)



You're welcome.

Scaling the inverted L I described to half size -- 30 feet vertical
and 45 feet horizontal -- will still give excellent performance.


73,


Kevin, WB4AIO.
--
http://kevinalfredstrom.com/

On May 21, 5:48*am, Kevin Alfred Strom
wrote:
bpnjensen wrote:
On May 20, 10:32 am, bpnjensen wrote:
...and I'm gonna use existing trees to put it up about 30 feet above
ground, 15 feet above my rooftop on a 5x100 foot suburban lot. *Power
lines both in front and back of my house, the ones behind are much
higher voltage, but not real high-tension wires.

All other things being equal, am I better off:

1 - Putting this thing up parallel to, or more perpendicular to, the
powerlines?

2 - Having the coax meet the wire at the base of the tree and
grounding it there, or running the coax up the tree and then depending
on the outer braid on the coax for ground purposes? *The coax is
grounded at the first termination point at my MFJ antenna phasing unit
using a short, heavy copper wire to a ground rod.

Thanks,
Bruce

Gentlemen, Peter and Kevin, thank you for the excellent ideas - some I
knew, some ARE new - I don't have a lot of room to experiment, but my
trees are situated so as to allow a generally perpendicular
orientation to the power lines, my main nemesis. *Unfortunately, 30
feet is about as high as I can practically put them, but it's higher
than what I have now, so anything is an improvement, eh? *Again,
thanks :-)

You're welcome.

Scaling the inverted L I described to half size -- 30 feet vertical
and 45 feet horizontal -- will still give excellent performance.

73,

Kevin, WB4AIO.
--http://kevinalfredstrom.com/- Hide quoted text -

- Show quoted text -

Thanks! Mine is likely to be 30 feet vert and about 65 feet horz.

Bruce

bpnjensen wrote:
On May 21, 5:48 am, Kevin Alfred Strom
wrote:
bpnjensen wrote:
On May 20, 10:32 am, bpnjensen wrote:
...and I'm gonna use existing trees to put it up about 30 feet above
ground, 15 feet above my rooftop on a 5x100 foot suburban lot. Power
lines both in front and back of my house, the ones behind are much
higher voltage, but not real high-tension wires.
All other things being equal, am I better off:
1 - Putting this thing up parallel to, or more perpendicular to, the
powerlines?
2 - Having the coax meet the wire at the base of the tree and
grounding it there, or running the coax up the tree and then depending
on the outer braid on the coax for ground purposes? The coax is
grounded at the first termination point at my MFJ antenna phasing unit
using a short, heavy copper wire to a ground rod.
Thanks,
Bruce
Gentlemen, Peter and Kevin, thank you for the excellent ideas - some I
knew, some ARE new - I don't have a lot of room to experiment, but my
trees are situated so as to allow a generally perpendicular
orientation to the power lines, my main nemesis. Unfortunately, 30
feet is about as high as I can practically put them, but it's higher
than what I have now, so anything is an improvement, eh? Again,
thanks :-)
You're welcome.

Scaling the inverted L I described to half size -- 30 feet vertical
and 45 feet horizontal -- will still give excellent performance.

73,

Kevin, WB4AIO.
--http://kevinalfredstrom.com/- Hide quoted text -

- Show quoted text -

Thanks! Mine is likely to be 30 feet vert and about 65 feet horz.

Bruce



That'll work well, too.

Putting a few radials on the ground (or, even better, elevated a few
feet above the ground) connected to the coaxial feedline's shield
will help the low angle (most distant) reception.

Recent studies indicate that radials don't need to be a quarter wave
long for best results as previously believed, either. About 195
divided by the frequency in MHz (with the answer in feet) is near
ideal, but they will still help at any length.

I've used flat rotor cable with the conductors pulled apart, or
separated strands of telephone PBX cable, stapled to the grassy yard
with staples made from cut up coat hangers bent into a U shape and
hammered over the wire every five or ten feet. If it's done
carefully, you can mow over them the same day without problems.
After a few weeks, the grass buries them and you can hardly tell the
wires are there.

If I was going to build a new inverted L today, I'd elevate the
feedpoint and radials about seven feet for higher efficiency -- but
it would look a bit more obtrusive.


Good luck with the antenna,


Kevin, WB4AIO.
--
http://kevinalfredstrom.com/

On May 21, 11:07*am, Kevin Alfred Strom kevin.st...@revilo-
oliver.com wrote:
bpnjensen wrote:
On May 21, 5:48 am, Kevin Alfred Strom
wrote:
bpnjensen wrote:
On May 20, 10:32 am, bpnjensen wrote:
...and I'm gonna use existing trees to put it up about 30 feet above
ground, 15 feet above my rooftop on a 5x100 foot suburban lot. *Power
lines both in front and back of my house, the ones behind are much
higher voltage, but not real high-tension wires.
All other things being equal, am I better off:
1 - Putting this thing up parallel to, or more perpendicular to, the
powerlines?
2 - Having the coax meet the wire at the base of the tree and
grounding it there, or running the coax up the tree and then depending
on the outer braid on the coax for ground purposes? *The coax is
grounded at the first termination point at my MFJ antenna phasing unit
using a short, heavy copper wire to a ground rod.
Thanks,
Bruce
Gentlemen, Peter and Kevin, thank you for the excellent ideas - some I
knew, some ARE new - I don't have a lot of room to experiment, but my
trees are situated so as to allow a generally perpendicular
orientation to the power lines, my main nemesis. *Unfortunately, 30
feet is about as high as I can practically put them, but it's higher
than what I have now, so anything is an improvement, eh? *Again,
thanks :-)
You're welcome.

Scaling the inverted L I described to half size -- 30 feet vertical
and 45 feet horizontal -- will still give excellent performance.

73,

Kevin, WB4AIO.
--http://kevinalfredstrom.com/-Hide quoted text -

- Show quoted text -

Thanks! *Mine is likely to be 30 feet vert and about 65 feet horz.

Bruce

That'll work well, too.

Putting a few radials on the ground (or, even better, elevated a few
feet above the ground) connected to the coaxial feedline's shield
will help the low angle (most distant) reception.

Recent studies indicate that radials don't need to be a quarter wave
long for best results as previously believed, either. About 195
divided by the frequency in MHz (with the answer in feet) is near
ideal, but they will still help at any length.

I've used flat rotor cable with the conductors pulled apart, or
separated strands of telephone PBX cable, stapled to the grassy yard
with staples made from cut up coat hangers bent into a U shape and
hammered over the wire every five or ten feet. If it's done
carefully, you can mow over them the same day without problems.
After a few weeks, the grass buries them and you can hardly tell the
wires are there.

If I was going to build a new inverted L today, I'd elevate the
feedpoint and radials about seven feet for higher efficiency -- but
it would look a bit more obtrusive.

Good luck with the antenna,

Kevin, WB4AIO.
--http://kevinalfredstrom.com/- Hide quoted text -

- Show quoted text -

Thanks again - my space for radials is super limited - no more than
about 15 feet in any direction, and usually less - but maybe if there
are enough of them it would help make up for it.

I have a pretty good ground here - near the edge of SF Bay and only
about 10 feet above sea level, our ground water is pretty brackish and
seeps upward too. I don't know that this would help with the low-
angle reception, though. Maybe a ground rod plus attached radials?

Bruce

bpnjensen wrote:
On May 21, 11:07 am, Kevin Alfred Strom kevin.st...@revilo-
oliver.com wrote:
bpnjensen wrote:
On May 21, 5:48 am, Kevin Alfred Strom
wrote:
bpnjensen wrote:
On May 20, 10:32 am, bpnjensen wrote:
...and I'm gonna use existing trees to put it up about 30 feet above
ground, 15 feet above my rooftop on a 5x100 foot suburban lot. Power
lines both in front and back of my house, the ones behind are much
higher voltage, but not real high-tension wires.
All other things being equal, am I better off:
1 - Putting this thing up parallel to, or more perpendicular to, the
powerlines?
2 - Having the coax meet the wire at the base of the tree and
grounding it there, or running the coax up the tree and then depending
on the outer braid on the coax for ground purposes? The coax is
grounded at the first termination point at my MFJ antenna phasing unit
using a short, heavy copper wire to a ground rod.
Thanks,
Bruce
Gentlemen, Peter and Kevin, thank you for the excellent ideas - some I
knew, some ARE new - I don't have a lot of room to experiment, but my
trees are situated so as to allow a generally perpendicular
orientation to the power lines, my main nemesis. Unfortunately, 30
feet is about as high as I can practically put them, but it's higher
than what I have now, so anything is an improvement, eh? Again,
thanks :-)
You're welcome.
Scaling the inverted L I described to half size -- 30 feet vertical
and 45 feet horizontal -- will still give excellent performance.
73,
Kevin, WB4AIO.
--http://kevinalfredstrom.com/-Hide quoted text -
- Show quoted text -
Thanks! Mine is likely to be 30 feet vert and about 65 feet horz.
Bruce
That'll work well, too.

Putting a few radials on the ground (or, even better, elevated a few
feet above the ground) connected to the coaxial feedline's shield
will help the low angle (most distant) reception.

Recent studies indicate that radials don't need to be a quarter wave
long for best results as previously believed, either. About 195
divided by the frequency in MHz (with the answer in feet) is near
ideal, but they will still help at any length.

I've used flat rotor cable with the conductors pulled apart, or
separated strands of telephone PBX cable, stapled to the grassy yard
with staples made from cut up coat hangers bent into a U shape and
hammered over the wire every five or ten feet. If it's done
carefully, you can mow over them the same day without problems.
After a few weeks, the grass buries them and you can hardly tell the
wires are there.

If I was going to build a new inverted L today, I'd elevate the
feedpoint and radials about seven feet for higher efficiency -- but
it would look a bit more obtrusive.

Good luck with the antenna,

Kevin, WB4AIO.
--http://kevinalfredstrom.com/- Hide quoted text -

- Show quoted text -

Thanks again - my space for radials is super limited - no more than
about 15 feet in any direction, and usually less - but maybe if there
are enough of them it would help make up for it.

I have a pretty good ground here - near the edge of SF Bay and only
about 10 feet above sea level, our ground water is pretty brackish and
seeps upward too. I don't know that this would help with the low-
angle reception, though. Maybe a ground rod plus attached radials?

Bruce



That sounds good. The brackish water in the far field will
definitely help. The inverted L will work without the radials, just
not as well for the more distant stations.


All the best,



Kevin, WB4AIO.
--
http://kevinalfredstrom.com/

On May 21, 11:25*am, Kevin Alfred Strom kevin.st...@revilo-
oliver.com wrote:
bpnjensen wrote:
On May 21, 11:07 am, Kevin Alfred Strom kevin.st...@revilo-
oliver.com wrote:
bpnjensen wrote:
On May 21, 5:48 am, Kevin Alfred Strom
wrote:
bpnjensen wrote:
On May 20, 10:32 am, bpnjensen wrote:
...and I'm gonna use existing trees to put it up about 30 feet above
ground, 15 feet above my rooftop on a 5x100 foot suburban lot. *Power
lines both in front and back of my house, the ones behind are much
higher voltage, but not real high-tension wires.
All other things being equal, am I better off:
1 - Putting this thing up parallel to, or more perpendicular to, the
powerlines?
2 - Having the coax meet the wire at the base of the tree and
grounding it there, or running the coax up the tree and then depending
on the outer braid on the coax for ground purposes? *The coax is
grounded at the first termination point at my MFJ antenna phasing unit
using a short, heavy copper wire to a ground rod.
Thanks,
Bruce
Gentlemen, Peter and Kevin, thank you for the excellent ideas - some I
knew, some ARE new - I don't have a lot of room to experiment, but my
trees are situated so as to allow a generally perpendicular
orientation to the power lines, my main nemesis. *Unfortunately, 30
feet is about as high as I can practically put them, but it's higher
than what I have now, so anything is an improvement, eh? *Again,
thanks :-)
You're welcome.
Scaling the inverted L I described to half size -- 30 feet vertical
and 45 feet horizontal -- will still give excellent performance.
73,
Kevin, WB4AIO.
--http://kevinalfredstrom.com/-Hidequoted text -
- Show quoted text -
Thanks! *Mine is likely to be 30 feet vert and about 65 feet horz.
Bruce
That'll work well, too.

Putting a few radials on the ground (or, even better, elevated a few
feet above the ground) connected to the coaxial feedline's shield
will help the low angle (most distant) reception.

Recent studies indicate that radials don't need to be a quarter wave
long for best results as previously believed, either. About 195
divided by the frequency in MHz (with the answer in feet) is near
ideal, but they will still help at any length.

I've used flat rotor cable with the conductors pulled apart, or
separated strands of telephone PBX cable, stapled to the grassy yard
with staples made from cut up coat hangers bent into a U shape and
hammered over the wire every five or ten feet. If it's done
carefully, you can mow over them the same day without problems.
After a few weeks, the grass buries them and you can hardly tell the
wires are there.

If I was going to build a new inverted L today, I'd elevate the
feedpoint and radials about seven feet for higher efficiency -- but
it would look a bit more obtrusive.

Good luck with the antenna,

Kevin, WB4AIO.
--http://kevinalfredstrom.com/-Hide quoted text -

- Show quoted text -

Thanks again - my space for radials is super limited - no more than
about 15 feet in any direction, and usually less - but maybe if there
are enough of them it would help make up for it.

I have a pretty good ground here - near the edge of SF Bay and only
about 10 feet above sea level, our ground water is pretty brackish and
seeps upward too. *I don't know that this would help with the low-
angle reception, though. *Maybe a ground rod plus attached radials?

Bruce

That sounds good. The brackish water in the far field will
definitely help. The inverted L will work without the radials, just
not as well for the more distant stations.

All the best,

Kevin, WB4AIO.
--http://kevinalfredstrom.com/- Hide quoted text -

- Show quoted text -

Sounds like radials are the ticket - thanks!