Receiving Loop Antenna Question
 

Richard Clark wrote:
Sounds like something the spooks would listen to.

Whereas now they're listening to this:
http://www.winradio.com/home/g526e-ep.htm

Receiving Loop Antenna Question
 

"Richard Clark" wrote in message
...


snip

After the capture of the USS Pueblo, it was said by my buddies that
Marine sentries were posted at the entrances to the comm room - "just
in case."

Of course, this was a lead they offered so I would ask "To protect
them from the boarders?" to which they would say "No, the Marines
would go in and shoot the CTs." This was similar to my own days
aboard the USS Holland, which, when it went out to sea was accompanied
by a submarine whose reputed orders were to sink us if we were in
jeopardy of being taken over. We had a technical library full of
systems plans for the Boomers.

I was a CT from 1962 to 1972, when I foolishly volunteered for conversion to
EW (but that's another story). A few CT's were ordered to sensitive
assignments aboard submarines and the rumors ran hot and heavy for that
program, too. They included, "You need uniforms with other rating insignia.
Nobody can see a CT coming off a submarine." and "On liberty overseas, you
have an armed guard with you to shoot you if there's any chance you'll be
captured."

There is no greater rumor mill than the US military. (If asked, I'm ready
with a "square needle in the left nut" story.)

Receiving Loop Antenna Question
 

On Sun, 25 Jan 2009 14:27:33 -0800 (PST), wrote:

On Jan 25, 9:52*am, Cecil Moore wrote:
wrote:
My 16 inch diameter circle loop for MW uses 12 turns.

I know multiple loop antennas are lossy for transmitting.
Are they adequate for receiving because of the AGC dynamic
range in the receiver?
--
73, Cecil *http://www.w5dxp.com

I'm not sure how the AGC comes into play here..
The 16 inch antenna provides plenty enough signal,
even with no preamp used. You could turn the AGC on
or off, wouldn't really matter. No different than any
other antenna you might connect in that regard.
They are lossy for transmitting, but on the MW bands
you have so much excess signal level it's not an
issue as far as receiving. Note the ferrite bar antenna,
which is even more lossy than the open loops I use.
It has no problem providing enough signal for a
cheap portable radio.
You might be surprised just how much level you can
get from a tuned small loop on the low bands.
As an example, that 16 inch loop provides more
signal than the whip on a car. I once tried it with a
delco radio in my truck. I hooked the loop up to it,
and it was as hot as a firecracker vs the standard
whip.
The catch is the system is very high Q, and requires
constant tuning of the cap as you change frequency.

That bites you when you use resonant loops. Of course non-resonant
loops don't have nearly the effective performance. Initial
selectivity to reduce the noise bandwidth before amplification or
mixing is why it is so common.

Receiving Loop Antenna Question
 

On Mon, 26 Jan 2009 18:16:22 -0000, "christofire"
wrote:


"Art Unwin" wrote in message
...
On Jan 26, 8:38 am, "christofire" wrote:
"Art Unwin" wrote in message

8

Hi Chris,
I need a bit more with respect to your response in more layman terms

When a multi turn helix is generated it can be used for both
transmitting and receiving.
When generating two helix antennas where one is contra wound and both
are connected at the top
you are saying that it will NOT be suitable for receiving !
We know by common use that the single helix is good for transmitt and
receive . So what exactly
does the addition of the contra winding do to prevent the combination
from receiving?
Looking forward to your take on the question.
Best regards
Art


OK. The term 'helix' is most often applied to the travelling-wave antenna
invented by John Kraus, often used at VHF and above, which generates or
receives a circularly-polarised wave predominantly in the direction of its
axis. It is also used in 'normal-mode helix' for the type of monopole
element often found on walkie talkies, that generates and receives a
linearly-polarised wave. Both of these are connected to electronics at one
end only.

The discussion was about loop antennas having one or more turns, with both
ends of the winding connected to electronics. This construction can also be
called a solenoid, but it would provoke confusion to call it a 'helix'.

When an alternating current is passed through a solenoid it generates a
magnetic field, H, through its centre and around it - the transmitting case.
When a solenoid is placed in an alternating magnetic field, if any lines of
magnetic force pass through its winding it will generate an electro-motive
force (EMF) from which current can be drawn to operate a receiver - the
receiving case.

In the transmitting case the physical characteristics (described by the
intrinsic impedance) of 'space' - the air surrounding the solenoid - cause
an electric field, E, to be generated from the alternating magnetic field,
in phase with the H field that caused it (viz. the intrinsic impedance of
space is real not complex) and together these in-phase E and H components
give rise to an electromagnetic wave. A fraction of the input power will be
radiated away from the solenoid in that wave, in directions where their
vector cross-product ExH is not zero. The field strength of either the E or
H component of the radiated wave will decay linearly with increasing
distance.

You can find a good account of this process in books like 'Antennas' by the
late John Kraus but it isn't possible to get very far without use of
mathematics. Chapter 7 of 'Antennas for all applications' by Kraus and
Marhefka, the 2002 edition, covers all this in greater detail and would be
worth obtaining if you're interested.

The 'sense' (i.e. clockwise/anticlockwise with respect to some datum) of the
winding of a solenoid, and the direction of the current applied, affect the
polarity of the magnetic field it produces, and vice versa for the receiving
case. Consequently, the phase with respect to time of the alternating H
field (and the alternating E-field component of the radiated electromagnetic
wave) depend on the 'sense' of the winding, but the polarisation of the
radiated wave depends on the alignment of the axis of the solenoid. By
convention, 'polarisation' is the angular direction of the E field in the
outgoing wave, which is perpendicular to the H-field component, and both are
perpendicular to the direction of propagation, so solenoid with a horizontal
axis radiates a vertically-polarised (VP) radio wave - and receives best
from a VP wave; the ferrite-rod-in-a-broadcast-receiver case.

Back to my original point: if part of the winding of the solenoid is wound
in the opposite sense to the rest of the winding then its contribution to
the generated H field, or the EMF on receiving, will oppose the contribution
from the other part of the winding. If the winding has half in each
'sense', connected in series (like a non-inductive wire-wound resistor),
then it will not generate an H field or develop an EMF from an incident H
field, so it will not work as a transmitting or receiving antenna ... for
the reasons outlined above.

Enough?

Chris


Say Chris, how about you set your Outhouse Express news/mail client to
use a quote character. It is good manners in news groups.

Receiving Loop Antenna Question
 

"JosephKK" wrote in message
...
On Mon, 26 Jan 2009 18:16:22 -0000, "christofire"
wrote:

almighty snip -----

Say Chris, how about you set your Outhouse Express news/mail client to
use a quote character. It is good manners in news groups.


Joseph, please explain (and excuse my bad manners!) - use a quote character
for what?

Are you referring to my use of the pairs of single quotation marks 'xxx' in
what I'd written? I usually reserve double quotation marks "qqq" for actual
quotations; things that people have said ... but I suspect you're referring
to something else.

Chris

Receiving Loop Antenna Question
 

On Sun, 1 Feb 2009 19:51:34 -0000, "christofire"
wrote:


"JosephKK" wrote in message
.. .
On Mon, 26 Jan 2009 18:16:22 -0000, "christofire"
wrote:

almighty snip -----

Say Chris, how about you set your Outhouse Express news/mail client to
use a quote character. It is good manners in news groups.


Joseph, please explain (and excuse my bad manners!) - use a quote character
for what?

Are you referring to my use of the pairs of single quotation marks 'xxx' in
what I'd written? I usually reserve double quotation marks "qqq" for actual
quotations; things that people have said ... but I suspect you're referring
to something else.

Chris


****************************

An example follows:
On Mon, 26 Jan 2009 18:16:22 -0000, "christofire" wrote:

Hi Chris,
I need a bit more with respect to your response in more layman terms

When a multi turn helix is generated it can be used for both
transmitting and receiving.
When generating two helix antennas where one is contra wound and both
are connected at the top
you are saying that it will NOT be suitable for receiving !
We know by common use that the single helix is good for transmitt and
receive . So what exactly
does the addition of the contra winding do to prevent the combination
from receiving?
Looking forward to your take on the question.
Best regards
Art


OK. The term 'helix' is most often applied to the travelling-wave antenna
invented by John Kraus, often used at VHF and above, which generates or
receives a circularly-polarised wave predominantly in the direction of its
axis. It is also used in 'normal-mode helix' for the type of monopole
element often found on walkie talkies, that generates and receives a
linearly-polarised wave. Both of these are connected to electronics at one
end only.


This sample, directly above, shows no distinction between your writing
and the post you responded to. I pointed this out last week in
another thread. However, at the top of this post above the starred
line, you clearly follow quoting conventions.

73's
Richard Clark, KB7QHC

Receiving Loop Antenna Question
 

"Richard Clark" wrote in message
...
On Sun, 1 Feb 2009 19:51:34 -0000, "christofire"
wrote:


"JosephKK" wrote in message
. ..
On Mon, 26 Jan 2009 18:16:22 -0000, "christofire"
wrote:

almighty snip -----

Say Chris, how about you set your Outhouse Express news/mail client to
use a quote character. It is good manners in news groups.


Joseph, please explain (and excuse my bad manners!) - use a quote
character
for what?

Are you referring to my use of the pairs of single quotation marks 'xxx'
in
what I'd written? I usually reserve double quotation marks "qqq" for
actual
quotations; things that people have said ... but I suspect you're
referring
to something else.

Chris


****************************

An example follows:
On Mon, 26 Jan 2009 18:16:22 -0000, "christofire"
wrote:

Hi Chris,
I need a bit more with respect to your response in more layman terms

When a multi turn helix is generated it can be used for both
transmitting and receiving.
When generating two helix antennas where one is contra wound and both
are connected at the top
you are saying that it will NOT be suitable for receiving !
We know by common use that the single helix is good for transmitt and
receive . So what exactly
does the addition of the contra winding do to prevent the combination
from receiving?
Looking forward to your take on the question.
Best regards
Art


OK. The term 'helix' is most often applied to the travelling-wave
antenna
invented by John Kraus, often used at VHF and above, which generates or
receives a circularly-polarised wave predominantly in the direction of
its
axis. It is also used in 'normal-mode helix' for the type of monopole
element often found on walkie talkies, that generates and receives a
linearly-polarised wave. Both of these are connected to electronics at
one
end only.


This sample, directly above, shows no distinction between your writing
and the post you responded to. I pointed this out last week in
another thread. However, at the top of this post above the starred
line, you clearly follow quoting conventions.

73's
Richard Clark, KB7QHC


I have the 'Plain Text Settings' option 'Indent the original text with
when replying or forwarding' ticked in OE and I can't account for why it
isn't working. I guess an incomplete sequence of cascaded s could make
the historical record difficult to follow. I wonder if this has happened
when I have snipped the accumulated message trail.

Chris

Receiving Loop Antenna Question
 

"christofire" wrote in message
...

"Richard Clark" wrote in message
...
On Sun, 1 Feb 2009 19:51:34 -0000, "christofire"
wrote:


"JosephKK" wrote in message
...
On Mon, 26 Jan 2009 18:16:22 -0000, "christofire"
wrote:

almighty snip -----

Say Chris, how about you set your Outhouse Express news/mail client to
use a quote character. It is good manners in news groups.


Joseph, please explain (and excuse my bad manners!) - use a quote
character
for what?

Are you referring to my use of the pairs of single quotation marks 'xxx'
in
what I'd written? I usually reserve double quotation marks "qqq" for
actual
quotations; things that people have said ... but I suspect you're
referring
to something else.

Chris


****************************

An example follows:
On Mon, 26 Jan 2009 18:16:22 -0000, "christofire"
wrote:

Hi Chris,
I need a bit more with respect to your response in more layman terms

When a multi turn helix is generated it can be used for both
transmitting and receiving.
When generating two helix antennas where one is contra wound and both
are connected at the top
you are saying that it will NOT be suitable for receiving !
We know by common use that the single helix is good for transmitt and
receive . So what exactly
does the addition of the contra winding do to prevent the combination
from receiving?
Looking forward to your take on the question.
Best regards
Art


OK. The term 'helix' is most often applied to the travelling-wave
antenna
invented by John Kraus, often used at VHF and above, which generates or
receives a circularly-polarised wave predominantly in the direction of
its
axis. It is also used in 'normal-mode helix' for the type of monopole
element often found on walkie talkies, that generates and receives a
linearly-polarised wave. Both of these are connected to electronics at
one
end only.


This sample, directly above, shows no distinction between your writing
and the post you responded to. I pointed this out last week in
another thread. However, at the top of this post above the starred
line, you clearly follow quoting conventions.

73's
Richard Clark, KB7QHC


I have the 'Plain Text Settings' option 'Indent the original text with
when replying or forwarding' ticked in OE and I can't account for why it
isn't working. I guess an incomplete sequence of cascaded s could make
the historical record difficult to follow. I wonder if this has happened
when I have snipped the accumulated message trail.

Chris


its not your fault. some news senders, like art, send in a format that oe
can't figure out how to indent and . i have tried lots of combinations and
the only one that works is to send in html format with the vertical bar
quoting.

Receiving Loop Antenna Question
 

"Dave" wrote in message
...

"christofire" wrote in message
...

"Richard Clark" wrote in message
...
On Sun, 1 Feb 2009 19:51:34 -0000, "christofire"
wrote:


"JosephKK" wrote in message
m...
On Mon, 26 Jan 2009 18:16:22 -0000, "christofire"
wrote:

almighty snip -----

Say Chris, how about you set your Outhouse Express news/mail client to
use a quote character. It is good manners in news groups.


Joseph, please explain (and excuse my bad manners!) - use a quote
character
for what?

Are you referring to my use of the pairs of single quotation marks 'xxx'
in
what I'd written? I usually reserve double quotation marks "qqq" for
actual
quotations; things that people have said ... but I suspect you're
referring
to something else.

Chris


****************************

An example follows:
On Mon, 26 Jan 2009 18:16:22 -0000, "christofire"
wrote:

Hi Chris,
I need a bit more with respect to your response in more layman terms

When a multi turn helix is generated it can be used for both
transmitting and receiving.
When generating two helix antennas where one is contra wound and both
are connected at the top
you are saying that it will NOT be suitable for receiving !
We know by common use that the single helix is good for transmitt and
receive . So what exactly
does the addition of the contra winding do to prevent the combination
from receiving?
Looking forward to your take on the question.
Best regards
Art


OK. The term 'helix' is most often applied to the travelling-wave
antenna
invented by John Kraus, often used at VHF and above, which generates or
receives a circularly-polarised wave predominantly in the direction of
its
axis. It is also used in 'normal-mode helix' for the type of monopole
element often found on walkie talkies, that generates and receives a
linearly-polarised wave. Both of these are connected to electronics at
one
end only.


This sample, directly above, shows no distinction between your writing
and the post you responded to. I pointed this out last week in
another thread. However, at the top of this post above the starred
line, you clearly follow quoting conventions.

73's
Richard Clark, KB7QHC


I have the 'Plain Text Settings' option 'Indent the original text with
when replying or forwarding' ticked in OE and I can't account for why it
isn't working. I guess an incomplete sequence of cascaded s could
make the historical record difficult to follow. I wonder if this has
happened when I have snipped the accumulated message trail.

Chris


its not your fault. some news senders, like art, send in a format that oe
can't figure out how to indent and . i have tried lots of combinations
and the only one that works is to send in html format with the vertical
bar quoting.

Thank you for that ... and I gather some get equally irritated about people
sending HTML.

Chris

Receiving Loop Antenna Question
 

"christofire" wrote in message
...

"Dave" wrote in message
...

"christofire" wrote in message
...

"Richard Clark" wrote in message
...
On Sun, 1 Feb 2009 19:51:34 -0000, "christofire"
wrote:


"JosephKK" wrote in message
om...
On Mon, 26 Jan 2009 18:16:22 -0000, "christofire"
wrote:

almighty snip -----

Say Chris, how about you set your Outhouse Express news/mail client
to
use a quote character. It is good manners in news groups.


Joseph, please explain (and excuse my bad manners!) - use a quote
character
for what?

Are you referring to my use of the pairs of single quotation marks
'xxx' in
what I'd written? I usually reserve double quotation marks "qqq" for
actual
quotations; things that people have said ... but I suspect you're
referring
to something else.

Chris


****************************

An example follows:
On Mon, 26 Jan 2009 18:16:22 -0000, "christofire"
wrote:

Hi Chris,
I need a bit more with respect to your response in more layman terms

When a multi turn helix is generated it can be used for both
transmitting and receiving.
When generating two helix antennas where one is contra wound and both
are connected at the top
you are saying that it will NOT be suitable for receiving !
We know by common use that the single helix is good for transmitt and
receive . So what exactly
does the addition of the contra winding do to prevent the combination
from receiving?
Looking forward to your take on the question.
Best regards
Art


OK. The term 'helix' is most often applied to the travelling-wave
antenna
invented by John Kraus, often used at VHF and above, which generates
or
receives a circularly-polarised wave predominantly in the direction of
its
axis. It is also used in 'normal-mode helix' for the type of monopole
element often found on walkie talkies, that generates and receives a
linearly-polarised wave. Both of these are connected to electronics
at one
end only.


This sample, directly above, shows no distinction between your writing
and the post you responded to. I pointed this out last week in
another thread. However, at the top of this post above the starred
line, you clearly follow quoting conventions.

73's
Richard Clark, KB7QHC


I have the 'Plain Text Settings' option 'Indent the original text with
when replying or forwarding' ticked in OE and I can't account for why it
isn't working. I guess an incomplete sequence of cascaded s could
make the historical record difficult to follow. I wonder if this has
happened when I have snipped the accumulated message trail.

Chris


its not your fault. some news senders, like art, send in a format that
oe can't figure out how to indent and . i have tried lots of
combinations and the only one that works is to send in html format with
the vertical bar quoting.

Thank you for that ... and I gather some get equally irritated about
people sending HTML.

Chris

of course. i prefer the nice safe plain text, but i guess not everyone sees
it that way.