elektroda.net NewsGroups Forum Index - Repair Electronics - long wire antenna
klem kedidelhopper
Guest
Guest
Sat Mar 06, 2010 4:17 pm
A customer lives in an apartment house on the 17th floor. He wants to
use an old Hallicrafters AM and SW radio. He cannot put up a long wire
antenna in the conventional way, however he wants to "weave" a sort of
antenna outside on his terrace, sort of like a web, with insulators to
hold the wire in every bend off ground. In this way he hopes to
achieve the length of a long wire antenna in a confined space. Will
this scheme work? The other option would be to hang a 2 X 4 off the
edge of the terrace and drop a wire down with an insulator on it and
hope that he can secure it to a neighbors terrace several floors
below. Anyone have any thought on this problem. Thanks, Lenny
William Sommerwerck
Guest
Guest
Sat Mar 06, 2010 4:17 pm
In a very broad sense, the customer is correct. A 10m wire forms a 20m
half-wave antenna, pretty much regardless of how it's oriented or it snakes
around.
There are books on compact and hidden antennas you might want to look at.
It's not unlike a wing. Almost any surface flat on the bottom and curved on
the top can produce lift.
Fred McKenzie
Guest
Guest
Sun Mar 07, 2010 12:16 am
In article
<b95b2e30-d784-4658-ad49-af533ad62b50_at_g7g2000yqe.googlegroups.com>,
klem kedidelhopper <captainvideo462009_at_gmail.com> wrote:
Quote:
he wants to "weave" a sort of
antenna outside on his terrace, sort of like a web, with insulators to
hold the wire in every bend off ground.
antenna outside on his terrace, sort of like a web, with insulators to
hold the wire in every bend off ground.
Lenny-
This is a case of "try it and it will probably work".
I once lived in an apartment with a balcony that had a railing. Someone
before me had bolted a CB 3/8-24 mirror antenna mount to the rail. I
attached a 40 Meter mobile whip and used it as a transmit antenna. The
Kenwood TS-690SAT had no trouble matching it. It didn't get out very
well but reception was good.
For a general purpose shortwave antenna, a 102 inch CB Whip mounted this
way on the railing, might work quite well. It could stick out away from
the building. He could feed it with Co-Ax cable, or just another long
wire between the whip and the radio's antenna terminal.
Fred
hr(bob) hofmann@att.net
Guest
Guest
Sun Mar 07, 2010 12:23 am
On Mar 6, 8:17 am, klem kedidelhopper <captainvideo462...@gmail.com>
wrote:
Quote:
A customer lives in an apartment house on the 17th floor. He wants to
use an old Hallicrafters AM and SW radio. He cannot put up a long wire
antenna in the conventional way, however he wants to "weave" a sort of
antenna outside on his terrace, sort of like a web, with insulators to
hold the wire in every bend off ground. In this way he hopes to
achieve the length of a long wire antenna in a confined space. Will
this scheme work? The other option would be to hang a 2 X 4 off the
edge of the terrace and drop a wire down with an insulator on it and
hope that he can secure it to a neighbors terrace several floors
below. Anyone have any thought on this problem. Thanks, Lenny
use an old Hallicrafters AM and SW radio. He cannot put up a long wire
antenna in the conventional way, however he wants to "weave" a sort of
antenna outside on his terrace, sort of like a web, with insulators to
hold the wire in every bend off ground. In this way he hopes to
achieve the length of a long wire antenna in a confined space. Will
this scheme work? The other option would be to hang a 2 X 4 off the
edge of the terrace and drop a wire down with an insulator on it and
hope that he can secure it to a neighbors terrace several floors
below. Anyone have any thought on this problem. Thanks, Lenny
What is the railing on the deck, wood or metal? He needs to keep the
wire aeay from any metal.
Phil Allison
Guest
Guest
Sun Mar 07, 2010 3:11 am
"klem kedidelhopper"
Quote:
A customer lives in an apartment house on the 17th floor. He wants
to use an old Hallicrafters AM and SW radio.
** For AM broadcast, by far the best is to use a frame aerial.
Heaps of stuff on the net about making them.
Quote:
He cannot put up a long wire antenna in the conventional way,
** Chances are any SW reception will be very badly affected by RFI from the
thousands of nearby TVs, PCs and other assorted electronic devices using
SMPSs that all radiate interference in the SW band. Only the strongest
signals will be heard OK and them he can pick up on a whip antenna mounted
on a balcony railing.
..... Phil
Sjouke Burry
Guest
Guest
Sun Mar 07, 2010 3:38 am
hr(bob) hofmann_at_att.net wrote:
Quote:
On Mar 6, 8:17 am, klem kedidelhopper <captainvideo462...@gmail.com
wrote:
A customer lives in an apartment house on the 17th floor. He wants to
use an old Hallicrafters AM and SW radio. He cannot put up a long wire
antenna in the conventional way, however he wants to "weave" a sort of
antenna outside on his terrace, sort of like a web, with insulators to
hold the wire in every bend off ground. In this way he hopes to
achieve the length of a long wire antenna in a confined space. Will
this scheme work? The other option would be to hang a 2 X 4 off the
edge of the terrace and drop a wire down with an insulator on it and
hope that he can secure it to a neighbors terrace several floors
below. Anyone have any thought on this problem. Thanks, Lenny
What is the railing on the deck, wood or metal? He needs to keep the
wire aeay from any metal.
wrote:
A customer lives in an apartment house on the 17th floor. He wants to
use an old Hallicrafters AM and SW radio. He cannot put up a long wire
antenna in the conventional way, however he wants to "weave" a sort of
antenna outside on his terrace, sort of like a web, with insulators to
hold the wire in every bend off ground. In this way he hopes to
achieve the length of a long wire antenna in a confined space. Will
this scheme work? The other option would be to hang a 2 X 4 off the
edge of the terrace and drop a wire down with an insulator on it and
hope that he can secure it to a neighbors terrace several floors
below. Anyone have any thought on this problem. Thanks, Lenny
What is the railing on the deck, wood or metal? He needs to keep the
wire aeay from any metal.
Or use the railing as antenna.
Also, when sort on space, a loop antenna might be usefull.
Arfa Daily
Guest
Guest
Mon Mar 08, 2010 2:45 am
"William Sommerwerck" <grizzledgeezer_at_comcast.net> wrote in message
news:hmtoke$5hi$1_at_news.eternal-september.org...
Quote:
In a very broad sense, the customer is correct. A 10m wire forms a 20m
half-wave antenna, pretty much regardless of how it's oriented or it
snakes
around.
There are books on compact and hidden antennas you might want to look at.
It's not unlike a wing. Almost any surface flat on the bottom and curved
on
the top can produce lift.
half-wave antenna, pretty much regardless of how it's oriented or it
snakes
around.
There are books on compact and hidden antennas you might want to look at.
It's not unlike a wing. Almost any surface flat on the bottom and curved
on
the top can produce lift.
So how come a symmetrical wing, such as might be found on a stunt plane,
still flies, and most asymmetric wings fly quite happily upside down ? :-)
Arfa
Phil Allison
Guest
Guest
Mon Mar 08, 2010 2:51 am
"Arfa Daily"
Quote:
It's not unlike a wing. Almost any surface flat on the bottom and curved
on the top can produce lift.
So how come a symmetrical wing, such as might be found on a stunt plane,
still flies, and most asymmetric wings fly quite happily upside down ?
:-)
on the top can produce lift.
So how come a symmetrical wing, such as might be found on a stunt plane,
still flies, and most asymmetric wings fly quite happily upside down ?
:-)
** I ask people who *think* they know how a plane flys that same Q.
Stumps them all the time.
Goes to show how simple explanations are often highly flawed.
...... Phil
William Sommerwerck
Guest
Guest
Mon Mar 08, 2010 5:43 am
Quote:
It's not unlike a wing. Almost any surface flat on the
bottom and curved on the top can produce lift.
So how come a symmetrical wing, such as might be found
on a stunt plane, still flies, and most asymmetric wings fly
quite happily upside down ?
bottom and curved on the top can produce lift.
So how come a symmetrical wing, such as might be found
on a stunt plane, still flies, and most asymmetric wings fly
quite happily upside down ?
I don't know. But that wasn't the point I was making.
Guest
Mon Mar 08, 2010 10:35 am
On Sat, 6 Mar 2010 06:17:39 -0800 (PST), klem kedidelhopper
<captainvideo462009_at_gmail.com> wrote:
Quote:
A customer lives in an apartment house on the 17th floor. He wants to
use an old Hallicrafters AM and SW radio. He cannot put up a long wire
antenna in the conventional way, however he wants to "weave" a sort of
antenna outside on his terrace, sort of like a web, with insulators to
hold the wire in every bend off ground. In this way he hopes to
achieve the length of a long wire antenna in a confined space. Will
this scheme work? The other option would be to hang a 2 X 4 off the
edge of the terrace and drop a wire down with an insulator on it and
hope that he can secure it to a neighbors terrace several floors
below. Anyone have any thought on this problem. Thanks, Lenny
use an old Hallicrafters AM and SW radio. He cannot put up a long wire
antenna in the conventional way, however he wants to "weave" a sort of
antenna outside on his terrace, sort of like a web, with insulators to
hold the wire in every bend off ground. In this way he hopes to
achieve the length of a long wire antenna in a confined space. Will
this scheme work? The other option would be to hang a 2 X 4 off the
edge of the terrace and drop a wire down with an insulator on it and
hope that he can secure it to a neighbors terrace several floors
below. Anyone have any thought on this problem. Thanks, Lenny
With just a randomly oriented long wire you will get unpredictable
results.
A better idea would be to get a PVC form of three to six inches and
helically wind the wire. The exact length won't matter because you
do not have a specific frequency in mind. Generally the more wire the
better. Mount it vertically or if you like move it around for the best
reception.
Arfa Daily
Guest
Guest
Tue Mar 09, 2010 2:53 am
"Phil Allison" <phil_a_at_tpg.com.au> wrote in message
news:7vj3h1F7nuU1_at_mid.individual.net...
Quote:
"Arfa Daily"
It's not unlike a wing. Almost any surface flat on the bottom and curved
on the top can produce lift.
So how come a symmetrical wing, such as might be found on a stunt plane,
still flies, and most asymmetric wings fly quite happily upside down ?
:-)
** I ask people who *think* they know how a plane flys that same Q.
Stumps them all the time.
Goes to show how simple explanations are often highly flawed.
..... Phil
I saw an interesting dissertation on this some time back, which put forward
a much more complex but better believable theory as to how a wing flies. I
don't really remember the details, but it relied heavily on the wing's angle
of attack into the air, to produce the pressure differential, and hence
lift. I seem to recall that it was the opposite way round from the
'conventional' teaching of increased speed of the air over the top of the
wing reducing the pressure, and that this theory had the attack angle
causing compression under the wing, thereby increasing the pressure to
produce lift. I do, however, remember it saying that air has no
'intelligence', and just because two previously adjacent molecules became
divided above and below the wing, there was nothing to say that they had to
form back up in the same way as they left the back edge of the wing, which
would require the air to move faster over the longer upper surface. I
believe it did say that the air actually does travel faster over the curved
face of the wing, and that the fact that it does, does produce a reduction
in pressure. However, this reduction is small, and only contributes a very
limited amount of lift, compared to the main mechanism that's at work.
Arfa
William Sommerwerck
Guest
Guest
Tue Mar 09, 2010 3:00 am
Quote:
I saw an interesting dissertation on this some time back, which put
forward
a much more complex but better believable theory as to how a wing flies. I
don't really remember the details, but it relied heavily on the wing's
angle
of attack into the air, to produce the pressure differential, and hence
lift. I seem to recall that it was the opposite way round from the
'conventional' teaching of increased speed of the air over the top of the
wing reducing the pressure, and that this theory had the attack angle
causing compression under the wing, thereby increasing the pressure to
produce lift. I do, however, remember it saying that air has no
'intelligence', and just because two previously adjacent molecules became
divided above and below the wing, there was nothing to say that they had
to
form back up in the same way as they left the back edge of the wing, which
would require the air to move faster over the longer upper surface. I
believe it did say that the air actually does travel faster over the
curved
face of the wing, and that the fact that it does, does produce a reduction
in pressure. However, this reduction is small, and only contributes a very
limited amount of lift, compared to the main mechanism that's at work.
forward
a much more complex but better believable theory as to how a wing flies. I
don't really remember the details, but it relied heavily on the wing's
angle
of attack into the air, to produce the pressure differential, and hence
lift. I seem to recall that it was the opposite way round from the
'conventional' teaching of increased speed of the air over the top of the
wing reducing the pressure, and that this theory had the attack angle
causing compression under the wing, thereby increasing the pressure to
produce lift. I do, however, remember it saying that air has no
'intelligence', and just because two previously adjacent molecules became
divided above and below the wing, there was nothing to say that they had
to
form back up in the same way as they left the back edge of the wing, which
would require the air to move faster over the longer upper surface. I
believe it did say that the air actually does travel faster over the
curved
face of the wing, and that the fact that it does, does produce a reduction
in pressure. However, this reduction is small, and only contributes a very
limited amount of lift, compared to the main mechanism that's at work.
I see your reasoning, but I don't think it's right. If the air near the
surface of the wing did not travel faster over the top of the wing, there
would be a buildup of air at the front.
And let's not forget that little experiment where one blows over the top of
a strip of paper, demonstrating, Bernouilli's Law.
Of course, this isn't to say that there is /only one way/ for a wing to
produce lift. But I don't want to get involved in this. Again, the point I
was making has been completely missed. What else is new?
Rich Webb
Guest
Guest
Tue Mar 09, 2010 3:12 am
On Tue, 9 Mar 2010 01:53:39 -0000, "Arfa Daily"
<arfa.daily_at_ntlworld.com> wrote:
Quote:
I saw an interesting dissertation on this some time back, which put forward
a much more complex but better believable theory as to how a wing flies.
a much more complex but better believable theory as to how a wing flies.
It's not really that complex. Didn't you ever, as a kid, hold your arm
out the car window with your hand flat and "fly" it up and down as you
changed the angle of attack? That's really all that's necessary. An
airplane could fly (if not very efficiently) with wings made from flat
sheets of plywood.
--
Rich Webb Norfolk, VA
AZ Nomad
Guest
Guest
Tue Mar 09, 2010 3:29 am
On Mon, 08 Mar 2010 21:12:26 -0500, Rich Webb <bbew.ar_at_mapson.nozirev.ten> wrote:
Quote:
On Tue, 9 Mar 2010 01:53:39 -0000, "Arfa Daily"
arfa.daily_at_ntlworld.com> wrote:
I saw an interesting dissertation on this some time back, which put forward
a much more complex but better believable theory as to how a wing flies.
It's not really that complex. Didn't you ever, as a kid, hold your arm
out the car window with your hand flat and "fly" it up and down as you
changed the angle of attack? That's really all that's necessary. An
airplane could fly (if not very efficiently) with wings made from flat
sheets of plywood.
arfa.daily_at_ntlworld.com> wrote:
I saw an interesting dissertation on this some time back, which put forward
a much more complex but better believable theory as to how a wing flies.
It's not really that complex. Didn't you ever, as a kid, hold your arm
out the car window with your hand flat and "fly" it up and down as you
changed the angle of attack? That's really all that's necessary. An
airplane could fly (if not very efficiently) with wings made from flat
sheets of plywood.
All you've got there is an inclined plane. You aren't creating lift.
Try it without the car.
Rich Webb
Guest
Guest
Tue Mar 09, 2010 3:47 am
On Mon, 08 Mar 2010 20:29:02 -0600, AZ Nomad
<aznomad.3_at_PremoveOBthisOX.COM> wrote:
Quote:
On Mon, 08 Mar 2010 21:12:26 -0500, Rich Webb <bbew.ar_at_mapson.nozirev.ten> wrote:
On Tue, 9 Mar 2010 01:53:39 -0000, "Arfa Daily"
arfa.daily_at_ntlworld.com> wrote:
I saw an interesting dissertation on this some time back, which put forward
a much more complex but better believable theory as to how a wing flies.
It's not really that complex. Didn't you ever, as a kid, hold your arm
out the car window with your hand flat and "fly" it up and down as you
changed the angle of attack? That's really all that's necessary. An
airplane could fly (if not very efficiently) with wings made from flat
sheets of plywood.
All you've got there is an inclined plane. You aren't creating lift.
Try it without the car.
On Tue, 9 Mar 2010 01:53:39 -0000, "Arfa Daily"
arfa.daily_at_ntlworld.com> wrote:
I saw an interesting dissertation on this some time back, which put forward
a much more complex but better believable theory as to how a wing flies.
It's not really that complex. Didn't you ever, as a kid, hold your arm
out the car window with your hand flat and "fly" it up and down as you
changed the angle of attack? That's really all that's necessary. An
airplane could fly (if not very efficiently) with wings made from flat
sheets of plywood.
All you've got there is an inclined plane. You aren't creating lift.
Try it without the car.
The saying goes something like: with enough power, you could fly a
brick. The lift comes from the angle of attack.
--
Rich Webb Norfolk, VA
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