Receiving Loop Antenna Question
 

In message , Richard Clark
writes
On Wed, 28 Jan 2009 20:12:15 +0000, Ian Jackson
wrote:

Thanks for the advice, however......

Why? A half volt signal level

(that's surely one hell of an RF signal?)

I can see you don't know what environment you are living in. That, or
you live out in a pastoral setting and the house has no significant RF
contribution. Most of the world is urbanized and folks live within
short distances of large transmitters.

In the UK, most medium wave transmitters - and certainly those which are
high power - are located well out of town. I'm 20 miles west of London,
and the nearest MW TX is about 25 miles away (20 miles north of London,
the area which it is intended to serve).

Varicap diodes will always suffer from having their capacitance
modulated by an RF signal impressed upon them. However, they do seem to
work well enough - even when the RF level is pretty high (which must be
the case especially with varicap-tuned oscillators - ie most VCOs and
PLL systems).

You don't put the Varicap into the high level part of the circuit.
This is obvious from the outset.

Surely it is at the high voltage part of the circuit where the tuning
capacitor will be most effective in tuning (ie most kHz per pF)?

Presumably, the effect of this modulation will be to generate
intermodulation products. In VCOs, this will simply appear as harmonics
of the oscillator signal (which you would get anyway - even with a
conventional tuning capacitor).

A conventional cap (and a conventional inductor, much less) will not
contribute harmonics because it is linear.

Well, of course it won't. And neither will be an inductor (especially if
it's air-cored, as in a loop antenna).

Harmonics comes from
nonlinear components added by the circuit (partial conduction of an
active component that aids in the oscillation).

Where multiple-frequency signals are
present (like you have with the receiving loop), the most apparent
effect of the modulation of the diode capacity will appear as
crossmodulation and other nasties on the other signals in the passband.
However, as varicaps ARE used for the tuning of the input of receiver RF
stages, how do they 'get away with it'?

They don't if you are in such an environment. Again, if you don't
know your environment, then it's all a crap shoot. There is no
"getting away with it." The alternative is that the designer of a
product fully anticipated these issues and purposely chose a design
that minimized the effect of accidental contributions.

That's what I am interested in finding out. Just how DO they make
varicap diodes work adequately in (say) receiver front ends?

Not all
designers are up to speed on the topic. The web is full of reported
failed projects that do not take bias Z and filtering into
consideration.

This swing is also a problem for PIN diodes used as voltage variable
attenuators.

My understanding of things is that the effectiveness of PIN diodes
relies on them having a very poor performance at RF (especially at VHF
and UHF). In attenuator circuits, they are forward biassed, and the DC
current passing through them varies their RF resistance. However, the
charges flowing through the junction are so 'sluggish' that they don't
react to the rapidly-changing RF voltages. There is therefore negligible
modulation of the RF resistance by the RF signals passing though them.

Poor performance when a PIN diode is first and foremost a diode for RF
and microwave applications? Only if you are using it for the wrong
reason (like using a 1N23 for 120V 60HZ power rectification).

My main personal experience with PIN diodes has been limited to their
use as 'variable resistors' in matched-impedance variable attenuators in
cable TV equipment. The essential characteristic is that there is a
chunk of ordinary (intrinsic) silicon between the P and the N layers. If
the RF signal alternates quickly enough, the electrons don't have time
to travel across the intrinsic layer before the polarity changes. As a
result, the diodes don't rectify. The higher the frequency, the better
they get at 'not rectifying'.

PIN diodes are used as resistors and switches, not rectifiers.

See above.

Further, don't confuse the switch application as meaning fast turn-off
in the pico-to-subnanoseconds. Speed is relative to the application
of signal path steering where 100s of nanoseconds is more than
adequate.

While I've used ordinary diodes as RF switches, I can't remember if I
have used PIN diodes. I think that, at the RF levels involved in CATV,
an 1N4148 junction diode worked just as well or better.

Consult:
http://www.ieee.li/pdf/pin_diode_handbook.pdf

Thanks. Yes, I'll have a look, but it's how to use varicaps that I
really want to know about.
--

Receiving Loop Antenna Question
 

Ian Jackson wrote:
. . .
That's what I am interested in finding out. Just how DO they make
varicap diodes work adequately in (say) receiver front ends?
. . .

Very carefully. One of the main tricks is to severely limit the tuning
range by using fixed capacitors, switched as necessary, to make up the
bulk of the circuit capacitance. This reduces two serious problems,
nonlinearity which causes distortion, and temperature sensitivity.
Harmonic distortion can be mitigated by following the tuned circuit with
filters (provided that the total tuning range is narrow enough), but
this doesn't correct intermod problems caused by the nonlinearity. A
third potential problem if you use varicap for wide tuning range is that
the control voltage has to be heroically filtered to prevent any noise
or ripple from modulating the capacitance. The problem of nonlinear
tuning is often solved by using a control loop, for example an AFC to
detect whether the desired signal is properly tuned and to automatically
adjust if it isn't.

I remember one of my first encounters with a varicap, where I naively
used it as the bulk of the circuit capacitance in a homebrew VHF-to-BCB
converter. I was leaning over the prototype, trying to find a signal,
but hearing only hearing blip. blip-blip-blip. blip, sounding like
signals going by as if a tuning dial was being spun. Then I realized it
was synchronized with my breathing. Every time I exhaled,
blip-blip-blip-blip. Then when I inhaled, they'd go by a little more
slowly, the other way. That temperature sensitivity, incidentally, is
extremely difficult to compensate, since it's different at every reverse
bias setting. The only way to have a chance is to swamp the varicap C as
much as possible with fixed C, then approximately compensate the
remaining temperature drift.

Roy Lewallen, W7EL

Receiving Loop Antenna Question
 

Roy Lewallen wrote:
Ian Jackson wrote:
. . .
That's what I am interested in finding out. Just how DO they make
varicap diodes work adequately in (say) receiver front ends?
. . .

Very carefully.

Might it help to use strings of varicaps? Sure I've seen that
done somewhere.

Receiving Loop Antenna Question
 

"Richard Clark" wrote in message
...
On Wed, 28 Jan 2009 20:19:20 GMT, "Jerry"
wrote:

Hi Richard

I made a capacitator rotator for my 6 foot AM loop using a hobby shop
servo to rotate the air variable cap. It works quite well and the
components are affordable.
The 3 section air capacitor allowed the use of each section by switching
to the appropriate section with a TO-5 relay.

That is Brute Force to tune an AM loop, but sure makes sense and uses
affordable parts.

Jerry KD6JDJ


Hi Jerry,

You have certain advantages over most of the correspondents here. You
are something of a gear head, you know where to find things, you know
how to put them together, and you actually do it.

When I was a kid, I had the same bent, but my resources were from
government surplus when you needed 400Hz 26V supplies (or other such
oddities). It was back in the 60s when I started experimenting with
Varicaps except they were 1N23 style diodes sold for their Varicap
properties (which comes free with almost any diode); the real Varicaps
sold for far too much for my allowance. Wasn't much tuning ratio back
then either - about 3:1 to 5:1 - today's have more range than most air
caps.

73's
Richard Clark, KB7QHC

Hi Richard

I worked for Hoffman Labs in 1960 and had responsibility for designing and
developing a sweep frequency receiver for the US Navy. I used a varicap
to sweep the L.O.. I am not inclined to use a varicap where a lumped
capacitor will do the job.

Jerry KD6JDJ

Receiving Loop Antenna Question
 

Clifford Heath wrote:
Roy Lewallen wrote:
Ian Jackson wrote:
. . .
That's what I am interested in finding out. Just how DO they make
varicap diodes work adequately in (say) receiver front ends?
. . .

Very carefully.

Might it help to use strings of varicaps? Sure I've seen that
done somewhere.

The only advantage I can see is that it would increase the amount of
distortion for a given level of signal, since the amount of capacitance
change with signal voltage would decrease. The tradeoff would be a
reduction in the capacitance and an increase in the required tuning voltage.

Roy Lewallen, W7EL

Receiving Loop Antenna Question
 

Roy Lewallen wrote:
Clifford Heath wrote:
Might it help to use strings of varicaps? Sure I've seen that
done somewhere.
The only advantage I can see is that it would increase the amount of
distortion for a given level of signal

Decrease, I think you mean. And yes, that's what I was thinking of.

Receiving Loop Antenna Question
 

On Thu, 29 Jan 2009 01:05:33 GMT, "Jerry"
wrote:

Hi Richard

I worked for Hoffman Labs in 1960 and had responsibility for designing and
developing a sweep frequency receiver for the US Navy. I used a varicap
to sweep the L.O.. I am not inclined to use a varicap where a lumped
capacitor will do the job.


Hmmm, a swept frequency receiver for the Navy. Sounds like something
the spooks would listen to. Crypto or surveillance gear?

73's
Richard Clark, KB7QHC

Receiving Loop Antenna Question
 

"Richard Clark" wrote in message
...
On Thu, 29 Jan 2009 01:05:33 GMT, "Jerry"
wrote:

Hi Richard

I worked for Hoffman Labs in 1960 and had responsibility for designing
and
developing a sweep frequency receiver for the US Navy. I used a varicap
to sweep the L.O.. I am not inclined to use a varicap where a lumped
capacitor will do the job.


Hmmm, a swept frequency receiver for the Navy. Sounds like something
the spooks would listen to. Crypto or surveillance gear?

73's
Richard Clark, KB7QHC

Hi Richard

You figured that out rather well and quickly too.

Jerry KD6JDJ

Receiving Loop Antenna Question
 

On Thu, 29 Jan 2009 06:23:32 GMT, "Jerry"
wrote:


"Richard Clark" wrote in message
.. .
On Thu, 29 Jan 2009 01:05:33 GMT, "Jerry"
wrote:

Hi Richard

I worked for Hoffman Labs in 1960 and had responsibility for designing
and
developing a sweep frequency receiver for the US Navy. I used a varicap
to sweep the L.O.. I am not inclined to use a varicap where a lumped
capacitor will do the job.


Hmmm, a swept frequency receiver for the Navy. Sounds like something
the spooks would listen to. Crypto or surveillance gear?

73's
Richard Clark, KB7QHC

Hi Richard

You figured that out rather well and quickly too.

Jerry KD6JDJ


Hi Jerry,

I trained with CTs (Communication Techs, otherwise those who
maintained and used Crypto or surveillance gear). When they couldn't
figure out a technical problem they always called the Cal Lab (we had
total responsibility for anything electronic).

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 also served with pig-boat submariners who spoke in hushed tones
about the USS Thrasher and Scorpion. Then there was my time with the
CBs who had spent more time in Nam than any Marines.

There was a lot of Black Humor in those days.

73's
Richard Clark, KB7QHC

Receiving Loop Antenna Question
 

Clifford Heath wrote:
Roy Lewallen wrote:
Clifford Heath wrote:
Might it help to use strings of varicaps? Sure I've seen that
done somewhere.
The only advantage I can see is that it would increase the amount of
distortion for a given level of signal

Decrease, I think you mean. And yes, that's what I was thinking of.

Yep, sorry, I did mean decrease. Thanks for catching it.

Roy Lewallen, W7EL

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.

Receiving Loop Antenna Question
 

On Mon, 02 Feb 2009 22:47:14 GMT, "Dave" wrote:

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

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

Hi All,

Not everyone sees in HTML either, and getting drenched by all of those
superfluous mark up script tags doesn't add to the conversation.

Outlook has a horrible reputation for launching insecure processes and
for spreading virus through marked up pages - no one knows the risk
offered by the content of any post until they open it. I use Agent
which has a safe HTML renderer, but I still don't need someone's
infected posting sitting in the thread.

The addition of charts, graphs and pictures could be put to good use
here. It "might" even bring sense to contrary current flow of
gaussian vector particels. In that sense, HTML would be a virtue;
however that isn't the convention of an already established text-based
group. (And the counter graphics of contrary current flow "might"
bring a blush to the easily offended.)

But if we went fully marked-up - what new vistas for rhetorical
exploration would be found there! ....and it still wouldn't solve
anything.

73's
Richard Clark, KB7QHC

Receiving Loop Antenna Question
 

"JosephKK" wrote in message
...
On Sun, 25 Jan 2009 14:27:33 -0800 (PST), wrote:

snip

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.


I recall medium-size table radios having a loop antenna in/on the back
cover. I don't know whether there was also a ferrite rod inside.

Receiving Loop Antenna Question
 

"Richard Clark" wrote in message
...

snip

But if we went fully marked-up - what new vistas for rhetorical
exploration would be found there!

We'd have smiley-faces and frowney faces. That would be good ... wouldn't
it? (Just kidding. No brickbats, please.)

Receiving Loop Antenna Question
 

On Wed, 4 Feb 2009 00:18:59 -0800, "Sal M. Onella"
wrote:
But if we went fully marked-up - what new vistas for rhetorical
exploration would be found there!

We'd have smiley-faces and frowney faces. That would be good ... wouldn't
it? (Just kidding. No brickbats, please.)

:-(

Receiving Loop Antenna Question
 

On Wed, 4 Feb 2009 00:12:54 -0800, "Sal M. Onella"
wrote:


"JosephKK" wrote in message
.. .
On Sun, 25 Jan 2009 14:27:33 -0800 (PST), wrote:

snip

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.


I recall medium-size table radios having a loop antenna in/on the back
cover. I don't know whether there was also a ferrite rod inside.

There was not one in the clock radio that i grew up with. I know, i
had it apart by the time i was ten.

Receiving Loop Antenna Question
 

On Mon, 2 Feb 2009 22:37:57 -0000, "christofire"
wrote:


"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

I am not so sure that is only OE having a bad reaction to some other
non-conforming news reader. Just the same i can easily see OE getting
confused by a non-conforming news post more easily than any other news
client.

Receiving Loop Antenna Question
 

JosephKK wrote:
On Wed, 4 Feb 2009 00:12:54 -0800, "Sal M. Onella"


I recall medium-size table radios having a loop antenna in/on the back
cover. I don't know whether there was also a ferrite rod inside.

There was not one in the clock radio that i grew up with. I know, i
had it apart by the time i was ten.

Most 5 tube All-Americans had a loop glued inside the Masonite back
cover. Fewer had a loopstick.