dipole coiley?
 

hi

wanted to help a fellow ham set up an antenna on his terrace
it's kinda a best effort attempt naturally the building won't allow
anything 'outside' so he just has the confines of the terrace


the total length of the longest side of theterrace

about 15ft on the longest side so here is my question


i was going to use a sgc 237 as the dipole 'center' and extend the legs
from there

since the total space is short would it be more advantages to make the
leggs a coil like a slinky? will this be of any real benifit?

if so how many ''turns'' and how big dia each ''coil''


my other option was to mount the sgc on the center of the celing extend
the dipole horizontally about 7ft each side then down to the floor
vertically like upside down U



i wondered how a loaded verticle would be or even using a verticle whip
into the sgc because i am not shure how i could make a 'radial'
/counterpoise

i'd like to give him at least 40m to 10 i realize that the sgc
really can 'tune ' anything but if it's too far outa wack (away from
resonance etc) it would just work poorly



he put up a glass metal framed enclousure around the terrace the metal
is isolated but a strange shape for an antenna i could try to load
that perhaps using a wire around his apt as the counterpoise? would
this be effective?


he's up about 20 stories on a high point everything elese is lower far
as eye can see to the horizon


any help is surly appreciated he's an old timer that wants to get back
on the air


ml

dipole coiley?
 

ml wrote:
wanted to help a fellow ham set up an antenna on his terrace

I would be inclined to lay down as large a ground plane as
possible, i.e. floor the terrace with hardware cloth. Then
put up the longest possible center-loaded vertical in the
center of the ground plane. He has many of the same
constraints as a mobile antenna.
--
73, Cecil http://www.w5dxp.com

cloth?: dipole coiley?
 

In article ,
Cecil Moore wrote:

ml wrote:
wanted to help a fellow ham set up an antenna on his terrace

I would be inclined to lay down as large a ground plane as
possible, i.e. floor the terrace with hardware cloth. Then
put up the longest possible center-loaded vertical in the
center of the ground plane. He has many of the same
constraints as a mobile antenna.

thanks for the responce cecil, a little dissapointed more havn't
responded maybe i blame my poor writing skills but i'd really like to
help this guy out

what is hardwire cloth? never heard of it or did mean that just
figuratively

thanks and happy newyear to you and family

cloth?: dipole coiley?
 

ml wrote:
what is hardwire cloth? never heard of it or did mean that just
figuratively

Hardware cloth is a wire matrix where all the wires
are soldered together. The openings are square and
about 1/4"-1/2" on the sides. It is commonly used
for small animal cages. I'm sure you know what it
looks like, just not familiar with its name. It makes
a better ground plane than chicken wire or hog wire.
It also makes a good top/end hat.
--
73, Cecil http://www.w5dxp.com

dipole coiley?
 

ml wrote:
hi

wanted to help a fellow ham set up an antenna on his terrace
it's kinda a best effort attempt naturally the building won't allow
anything 'outside' so he just has the confines of the terrace


the total length of the longest side of theterrace

about 15ft on the longest side so here is my question


i was going to use a sgc 237 as the dipole 'center' and extend the legs
from there

since the total space is short would it be more advantages to make the
leggs a coil like a slinky? will this be of any real benifit?

if so how many ''turns'' and how big dia each ''coil''


my other option was to mount the sgc on the center of the celing extend
the dipole horizontally about 7ft each side then down to the floor
vertically like upside down U



i wondered how a loaded verticle would be or even using a verticle whip
into the sgc because i am not shure how i could make a 'radial'
/counterpoise

i'd like to give him at least 40m to 10 i realize that the sgc
really can 'tune ' anything but if it's too far outa wack (away from
resonance etc) it would just work poorly



he put up a glass metal framed enclousure around the terrace the metal
is isolated but a strange shape for an antenna i could try to load
that perhaps using a wire around his apt as the counterpoise? would
this be effective?


he's up about 20 stories on a high point everything elese is lower far
as eye can see to the horizon


any help is surly appreciated he's an old timer that wants to get back
on the air


ml

Have you considered a horizontal loop fed with the SGC? At 20 stories,
it ought to be quite a performer. I assume the circumference of the
terrace is about 45 feet. The metal frame you mentioned could be a
problem, but it is a fairly costless and quick option to try.

Chuck

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
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cloth?: dipole coiley?
 

On Sun, 07 Jan 2007 07:35:39 -0600, Cecil Moore
wrote:

ml wrote:
what is hardwire cloth? never heard of it or did mean that just
figuratively

Hardware cloth is a wire matrix where all the wires
are soldered together. The openings are square and
about 1/4"-1/2" on the sides. It is commonly used
for small animal cages. I'm sure you know what it
looks like, just not familiar with its name. It makes
a better ground plane than chicken wire or hog wire.
It also makes a good top/end hat.

Check the link below.
http://www.phoenixwirecloth.com/

cloth?: dipole coiley?
 

helmsman wrote:
Check the link below.
http://www.phoenixwirecloth.com/

That is quite extensive. Here's more what I
had in mind:

http://www.twpinc.com/twp/jsp/product.jsp?type=4

http://www.marcospecialtysteel.com/hardwarecloth.htm
--
73, Cecil http://www.w5dxp.com

cloth?: dipole coiley?
 

Cecil Moore wrote:
helmsman wrote:
Check the link below.
http://www.phoenixwirecloth.com/

That is quite extensive. Here's more what I
had in mind:

http://www.twpinc.com/twp/jsp/product.jsp?type=4

http://www.marcospecialtysteel.com/hardwarecloth.htm

There is also expanded aluminum mesh (don't know if you already gave a
url with it.) A friend gave me a load of this stuff, he works in
demolition of buildings. The stuff was used in stuccoing buildings.
All I had to do was go to his yard and persuade the mesh out of the
stucco with a hammer.

Problems I ran into was soldering it together, soldering aluminum takes
quite a bit more skill than copper!!!

Regards,
JS

dipole coiley?
 

He might try a horizontal loop. Just run a wire around the perimeter as
high as possible, with as large an area as possible. Then feed it with open
wire line, or a short coax into the SGC tuner. At 15 feet per side, it
should be good down to 20 meters, and with some lower effectiveness at 40.


"ml" wrote in message
...
hi

wanted to help a fellow ham set up an antenna on his terrace
it's kinda a best effort attempt naturally the building won't allow
anything 'outside' so he just has the confines of the terrace


the total length of the longest side of theterrace

about 15ft on the longest side so here is my question


i was going to use a sgc 237 as the dipole 'center' and extend the legs
from there

since the total space is short would it be more advantages to make the
leggs a coil like a slinky? will this be of any real benifit?

if so how many ''turns'' and how big dia each ''coil''


my other option was to mount the sgc on the center of the celing extend
the dipole horizontally about 7ft each side then down to the floor
vertically like upside down U



i wondered how a loaded verticle would be or even using a verticle whip
into the sgc because i am not shure how i could make a 'radial'
/counterpoise

i'd like to give him at least 40m to 10 i realize that the sgc
really can 'tune ' anything but if it's too far outa wack (away from
resonance etc) it would just work poorly



he put up a glass metal framed enclousure around the terrace the metal
is isolated but a strange shape for an antenna i could try to load
that perhaps using a wire around his apt as the counterpoise? would
this be effective?


he's up about 20 stories on a high point everything elese is lower far
as eye can see to the horizon


any help is surly appreciated he's an old timer that wants to get back
on the air


ml

cloth?: dipole coiley?
 

John Smith I wrote:
Problems I ran into was soldering it together, soldering aluminum takes
quite a bit more skill than copper!!!

For some reason, the standard galvanized-dipped
stuff is easy to solder.
--
73, Cecil http://www.w5dxp.com

cloth?: dipole coiley?
 

In article ,
Cecil Moore wrote:

John Smith I wrote:
Problems I ran into was soldering it together, soldering aluminum takes
quite a bit more skill than copper!!!

For some reason, the standard galvanized-dipped
stuff is easy to solder.

good idea technically speaking but i don't think i'll be able to hide
anyof this stuff in his apartment

if i go verticle i'd hope maybe to hide 2 counterpoise"" like wires
around the far walls but certainly not mesh

the only way i could think of using mesh is around the railing of the
terrace hanging it verticle and putting the verticle antenna part
ontop(higher)
the railing is concreate

cloth?: dipole coiley?
 

good idea technically speaking but i don't think i'll be able to hide
anyof this stuff in his apartment

if i go verticle i'd hope maybe to hide 2 counterpoise"" like wires
around the far walls but certainly not mesh

the only way i could think of using mesh is around the railing of the
terrace hanging it verticle and putting the verticle antenna part
ontop(higher)
the railing is concreate
Indoor/outdoor carpet over the mesh would be OK.

I get a little worried about more than a couple of watts around areas
with people.

The new TenTec rig that is built to remote over a Lan/internet will
add more options soon.
John Ferrell W8CCW

cloth?: dipole coiley?
 

John Ferrell wrote in
:

I get a little worried about more than a couple of watts around areas
with people.

Ah, this must be in the vein of "they have been unable to prove EMR
safe".

There are clear guidelines / rules on maximum permitted exposure to EMR
that should allow design and operation of a station with confidence that
it most unlikely to be an EMR hazard to one's self, family or the general
public. Understanding and applying this is just another facet of the
hobby today, though I concede it is beyond our new 6 hour hams (though
that is part of the reason for their low power limit, should they observe
it).

One of my current projects is a self contained field strength meter for
field measurement near a transmitting antenna. It consists of a small
single turn untuned square loop, terminated in a known load, a detector
and an inexpensive battery power LCD panel meter, all self contained
mounted on a non-conductive stick with no trailing wires. It is fairly
straight forward to produce an Antenna Factor / Freq chart using NEC, and
a detector calibration (Vout/Pin). Trials have been encouraging with good
correlation with expected field strength.

On the other hand, it has been demonstrated that UV radiation is a health
hazard, and there is no "safe" exposure level (ie a threshold below which
no changes will take place in living cells). If one took a balanced
approach, before becoming too concerned about EMR MPE, one would protect
one's self from ANY sunshine, direct or indirect.

If it appears that ham's brains have been addled by RF, they were
probably that way before exposure to EMR, it might just be a factor for
selection of hams. (You don't have to be mad to be a ham, but it helps!)

Owen

cloth?: dipole coiley?
 

On Mon, 08 Jan 2007 21:34:51 GMT, Owen Duffy wrote:

John Ferrell wrote in
:

I get a little worried about more than a couple of watts around areas
with people.


On the other hand, it has been demonstrated that UV radiation is a health
hazard, and there is no "safe" exposure level (ie a threshold below which
no changes will take place in living cells). If one took a balanced
approach, before becoming too concerned about EMR MPE, one would protect
one's self from ANY sunshine, direct or indirect.
I am there too. The effects seem to be accumulative to some of us...


If it appears that ham's brains have been addled by RF, they were
probably that way before exposure to EMR, it might just be a factor for
selection of hams. (You don't have to be mad to be a ham, but it helps!)

Owen

I managed to get an RF burn from a 25 watt nav transmitter once and it
hurt! It was slw to heal as well.

My problem is that I really don't know, I have yet to do that
homework.

I have a similar problem of my own in the near future. I have a 24
foot Winniebago RV that is at least skinned with fiber glass. I would
like to try HF mobile Lots of homework ahead...
John Ferrell W8CCW

cloth?: dipole coiley?
 

"John Ferrell" wrote in message
...
On Mon, 08 Jan 2007 21:34:51 GMT, Owen Duffy wrote:

John Ferrell wrote in
m:

I get a little worried about more than a couple of watts around areas
with people.


On the other hand, it has been demonstrated that UV radiation is a health
hazard, and there is no "safe" exposure level (ie a threshold below which
no changes will take place in living cells). If one took a balanced
approach, before becoming too concerned about EMR MPE, one would protect
one's self from ANY sunshine, direct or indirect.
I am there too. The effects seem to be accumulative to some of us...


If it appears that ham's brains have been addled by RF, they were
probably that way before exposure to EMR, it might just be a factor for
selection of hams. (You don't have to be mad to be a ham, but it helps!)

Owen

I managed to get an RF burn from a 25 watt nav transmitter once and it
hurt! It was slw to heal as well.

My problem is that I really don't know, I have yet to do that
homework.

I have a similar problem of my own in the near future. I have a 24
foot Winniebago RV that is at least skinned with fiber glass. I would
like to try HF mobile Lots of homework ahead...
John Ferrell W8CCW

I gave up trying to talk while driving, it only took one close call for me
to quit. After I set up camp I lay some radials out on the ground and set up
an 18 ft fibergalss whip. Vehicle has antennas for 10/11m and 2m.

cloth?: dipole coiley?
 

Jimmie D wrote:
I gave up trying to talk while driving, ...

While driving, I find it hard to talk on a cellphone
but easy to talk on a ham radio. There's something
about half-duplex, push-to-talk that makes it easier,
maybe that I don't have to talk and listen at the
same time.
--
73, Cecil http://www.w5dxp.com

cloth?: dipole coiley?
 

John Ferrell wrote:
"The effects seem to be accumulative to some of us."

Perhaps. Intensity, proximity, and radiated frequency are important in
my experience.

I worked years in a shortwave broadcasting plant where about a megawatt
was being continuously radiated around the clock. No one of the many
employees ever showed any effect from the exposure.

One the other hand, my ham friend, W5OQJ, was a movie projectionist. He
contracted a chest cold. In an attempt to "bake it out", he exposed his
chest to the the ultra violet from the electric arc of the projector.
Next morning, he was dead.

Best regards, Richard Harrison, KB5WZI

cloth?: dipole coiley?
 

"Richard Harrison" wrote in message
...
John Ferrell wrote:
"The effects seem to be accumulative to some of us."

Perhaps. Intensity, proximity, and radiated frequency are important in
my experience.

I worked years in a shortwave broadcasting plant where about a megawatt
was being continuously radiated around the clock. No one of the many
employees ever showed any effect from the exposure.

One the other hand, my ham friend, W5OQJ, was a movie projectionist. He
contracted a chest cold. In an attempt to "bake it out", he exposed his
chest to the the ultra violet from the electric arc of the projector.
Next morning, he was dead.

Best regards, Richard Harrison, KB5WZI

Sounds like a guy I knew that pressed his face against the open end of a
..6MW peak radar trying to fix his sinus problem. He developed cancer there.

cloth?: dipole coiley?
 

Jimmie D wrote:
Sounds like a guy I knew that pressed his face against the open end of a
.6MW peak radar trying to fix his sinus problem. He developed cancer there.

I know someone who drank water, and he got stomach cancer.

The effects of high intensity radar have been studied in great depth for
decades. As far as I know, no evidence has ever been found that they're
able to cause cancer.

Roy Lewallen, W7EL

cloth?: dipole coiley?
 

Richard Harrison wrote:
John Ferrell wrote:
"The effects seem to be accumulative to some of us."

Perhaps. Intensity, proximity, and radiated frequency are important in
my experience.
. . .

Sure enough, I've got indisputable proof. The longer I'm a ham, the
dimmer my eyesight and hearing, the shakier my hand, the unsteadier my
gait. I can't remember things as well as I used to. And I'm even growing
more hair out of my ears!

Watch out, this stuff is dangerous in the long haul!

Roy Lewallen, W7EL

cloth?: dipole coiley?
 

On Tue, 09 Jan 2007 13:12:58 -0800, Roy Lewallen
wrote:

Richard Harrison wrote:
John Ferrell wrote:
"The effects seem to be accumulative to some of us."

Perhaps. Intensity, proximity, and radiated frequency are important in
my experience.
. . .

Sure enough, I've got indisputable proof. The longer I'm a ham, the
dimmer my eyesight and hearing, the shakier my hand, the unsteadier my
gait. I can't remember things as well as I used to. And I'm even growing
more hair out of my ears!

Watch out, this stuff is dangerous in the long haul!

Roy Lewallen, W7EL

Yea, me too Roy. Bun unlike you I hot jumped Loran transmitting
towers. And for those not aware the transmitting power was one
mega-watt. On a damp day you sure could draw a heck of an arc when you
jumped off.

Danny, K6MHE

cloth?: dipole coiley?
 

Roy Lewallen wrote in
:

Richard Harrison wrote:
John Ferrell wrote:
"The effects seem to be accumulative to some of us."

Perhaps. Intensity, proximity, and radiated frequency are important
in my experience.
. . .

Sure enough, I've got indisputable proof. The longer I'm a ham, the
dimmer my eyesight and hearing, the shakier my hand, the unsteadier my
gait. I can't remember things as well as I used to. And I'm even
growing more hair out of my ears!

Watch out, this stuff is dangerous in the long haul!

Epidemiological studies often provide "indisputable proof" to people
looking for support for their "beliefs". For instance, if they don't
want a mobile phone tower in their visual environment, then the results
of such studies are elevated to "indisputable proof" to oppose such
structures.

The illogical thing is that there is more opposition to taller towers,
though they are safer from an EMR perspective (both in terms of the
radiation from the tower, and the power radiated by mobiles to
communicate with the tower). That indicates to me that EMR safety is not
uppermost in their minds, and their concern is a misrepresentation.

Thing is, when you depend on epidemiological studies, while you can
create a lot of FUD (fear, uncertainty and doubt), you can't really
prove anything safe.

Owen

cloth?: dipole coiley?
 

In the U.S., unfortunately, "proof" that something has caused harm means
convincing a jury consisting of people who, on the average, probably
couldn't find Japan on a map and around half of whom don't believe in
evolution.

Roy Lewallen, W7EL

Owen Duffy wrote:

Epidemiological studies often provide "indisputable proof" to people
looking for support for their "beliefs". For instance, if they don't
want a mobile phone tower in their visual environment, then the results
of such studies are elevated to "indisputable proof" to oppose such
structures.

The illogical thing is that there is more opposition to taller towers,
though they are safer from an EMR perspective (both in terms of the
radiation from the tower, and the power radiated by mobiles to
communicate with the tower). That indicates to me that EMR safety is not
uppermost in their minds, and their concern is a misrepresentation.

Thing is, when you depend on epidemiological studies, while you can
create a lot of FUD (fear, uncertainty and doubt), you can't really
prove anything safe.

Owen

cloth?: dipole coiley?
 

Roy Lewallen wrote:
In the U.S., unfortunately, "proof" that something has caused harm means
convincing a jury consisting of people who, on the average, probably
couldn't find Japan on a map and around half of whom don't believe in
evolution.


So thats why I didn't get pick the last time I was called for jury
duty!!! I could locate Japan! ;^)

- 73 de Mike KB3EIA -

cloth?: dipole coiley?
 

Is aluminium (baking) foil any good as a ground plane? How does it compare
to metal mesh?

cloth?: dipole coiley?
 

The short answer is that it would be very good at VHF and above, and
poorer at lower frequencies. How it would compare with a metal mesh
depends on the frequency, the nature of the mesh, and the application,
so there's no simple answer to the comparison question.

To make it reasonably opaque to currents and fields, it needs to be at
least several skin depths thick. As far as I've been able to tell,
aluminum foil is roughly 0.02 mm thick. That would be 3 skin depths at
about 150 MHz; below that frequency, it would be increasingly
transparent. Above that frequency, it would have the same resistance as
a group of separated wires having the same surface area. Because it has
such a large surface area, I'd expect it to do as well as or better than
most wire meshes down into the HF range. But as I said earlier, it depends.

Roy Lewallen, W7EL

David wrote:
Is aluminium (baking) foil any good as a ground plane? How does it compare
to metal mesh?