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-   -   TX Distance question (https://www.radiobanter.com/dx/10017-tx-distance-question.html)

Cecil Moore November 28th 04 08:50 PM

Bill Turner wrote:
Once the antenna is resonant, a simple L-C network will transform the
impedance to 50 ohms resistive and you are all set. Simple, cheap and
reliable, all the things a tuner is not.


And single-banded, one thing a tuner is not. :-)

The antenna need not be resonant. Under certain easily obtainable
conditions, the length of the open-wire transmission line can tune
a non-resonant antenna to system resonance and better the losses in
the coax feeding a resonant antenna. How to do that is described
on my web page.
--
73, Cecil http://www.qsl.net/w5dxp

Keyboard In The Wilderness November 28th 04 09:01 PM

Back to TX distance - you really need to get a good book on propagation and
understand the solar cycle and the characteristics of each band.

For example -- on 10M with the right time in the 11 year solar cycle -- a
minimum antenna and a few watts will work the world (at the right time of
day)

On 160M in the day time in the summer with low power -- you ain't going
anywhere

--
The Anon Keyboard
I doubt, therefore I might be



"Cecil Moore" wrote in message
...
Bill Turner wrote:
Once the antenna is resonant, a simple L-C network will transform the
impedance to 50 ohms resistive and you are all set. Simple, cheap and
reliable, all the things a tuner is not.


And single-banded, one thing a tuner is not. :-)

The antenna need not be resonant. Under certain easily obtainable
conditions, the length of the open-wire transmission line can tune
a non-resonant antenna to system resonance and better the losses in
the coax feeding a resonant antenna. How to do that is described
on my web page.
--
73, Cecil http://www.qsl.net/w5dxp




Keyboard In The Wilderness November 28th 04 09:01 PM

Back to TX distance - you really need to get a good book on propagation and
understand the solar cycle and the characteristics of each band.

For example -- on 10M with the right time in the 11 year solar cycle -- a
minimum antenna and a few watts will work the world (at the right time of
day)

On 160M in the day time in the summer with low power -- you ain't going
anywhere

--
The Anon Keyboard
I doubt, therefore I might be



"Cecil Moore" wrote in message
...
Bill Turner wrote:
Once the antenna is resonant, a simple L-C network will transform the
impedance to 50 ohms resistive and you are all set. Simple, cheap and
reliable, all the things a tuner is not.


And single-banded, one thing a tuner is not. :-)

The antenna need not be resonant. Under certain easily obtainable
conditions, the length of the open-wire transmission line can tune
a non-resonant antenna to system resonance and better the losses in
the coax feeding a resonant antenna. How to do that is described
on my web page.
--
73, Cecil http://www.qsl.net/w5dxp




Gary Schafer November 28th 04 09:15 PM

On Sun, 28 Nov 2004 12:06:48 -0800, Bill Turner
wrote:

On Sun, 28 Nov 2004 15:17:53 GMT, 'Doc wrote:

Since the backstay (or
frontstay) is ~there~ anyway, why not use it? Certainly not the
'best' thing in the world (whatever that is), but 'better' than most
alternative$.


There are insulators designed just for backstays which one could place
at the 16.4 foot level for 20 meters, or multiple locations for multiple
bands. In a home situation, I wouldn't care much but on a small boat on
the open sea, KISS could save your life, IMO.


Some people have a 'phobia' about tuners. If you don't want to
use one, that's fine.


The word "phobia" means a fear of. I'm certainly not afraid of tuners,
but I believe making the antenna right is better than using a device to
compensate for one that isn't. "Bias" would be a better word.

Once the antenna is resonant, a simple L-C network will transform the
impedance to 50 ohms resistive and you are all set. Simple, cheap and
reliable, all the things a tuner is not.


They do make 'things' much easier and the
difference in performance is 'acceptible' in most cases (acceptible
being relative).


Sigh.


It's kind of difficult to get a resonant quarter wave into a back stay
as you don't usually know where ground is. Ground can be any number of
feet from where the feed point is on a boat. Every thing above real
ground is antenna.

73
Gary K4FMX


Gary Schafer November 28th 04 09:15 PM

On Sun, 28 Nov 2004 12:06:48 -0800, Bill Turner
wrote:

On Sun, 28 Nov 2004 15:17:53 GMT, 'Doc wrote:

Since the backstay (or
frontstay) is ~there~ anyway, why not use it? Certainly not the
'best' thing in the world (whatever that is), but 'better' than most
alternative$.


There are insulators designed just for backstays which one could place
at the 16.4 foot level for 20 meters, or multiple locations for multiple
bands. In a home situation, I wouldn't care much but on a small boat on
the open sea, KISS could save your life, IMO.


Some people have a 'phobia' about tuners. If you don't want to
use one, that's fine.


The word "phobia" means a fear of. I'm certainly not afraid of tuners,
but I believe making the antenna right is better than using a device to
compensate for one that isn't. "Bias" would be a better word.

Once the antenna is resonant, a simple L-C network will transform the
impedance to 50 ohms resistive and you are all set. Simple, cheap and
reliable, all the things a tuner is not.


They do make 'things' much easier and the
difference in performance is 'acceptible' in most cases (acceptible
being relative).


Sigh.


It's kind of difficult to get a resonant quarter wave into a back stay
as you don't usually know where ground is. Ground can be any number of
feet from where the feed point is on a boat. Every thing above real
ground is antenna.

73
Gary K4FMX


Cecil Moore November 28th 04 10:01 PM

Bill Turner wrote:
A simple pigtail with a banana plug would make the L-network as multi
banded as you have L-networks. Still simple, cheap and reliable.


Let's see, would I rather switch knife switches at my operating
position or go outside in a Texas Thunder Storm to attach the
pigtails? At my age, I could develop pneumonia or catch the flu
(no flu shot this year). Pneumonia and/or flu is not simple or
cheap. Think I'll stick with my Ladder-Line Length Selector. :-)

Moral: Use virtually lossless transmission line and do all the
matching in the comfort of the shack.
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore November 28th 04 10:01 PM

Bill Turner wrote:
A simple pigtail with a banana plug would make the L-network as multi
banded as you have L-networks. Still simple, cheap and reliable.


Let's see, would I rather switch knife switches at my operating
position or go outside in a Texas Thunder Storm to attach the
pigtails? At my age, I could develop pneumonia or catch the flu
(no flu shot this year). Pneumonia and/or flu is not simple or
cheap. Think I'll stick with my Ladder-Line Length Selector. :-)

Moral: Use virtually lossless transmission line and do all the
matching in the comfort of the shack.
--
73, Cecil http://www.qsl.net/w5dxp

Keyboard In The Wilderness November 28th 04 10:31 PM

Bill I agree But
The original poster sed:

"My very first contacts were established with 2 land stations on 14300 at
100W that were about 1000 miles away. They both reported that my signal
was good and that it sounded like I was "sitting right next to them". I
have no idea if this was a good distance, great, or mediocre."

So I assume he was after contacts of several hundred (thousand) miles - not
ground wave.

My point was this for the 160M band (From a book on propagation)

"160 meters. Daytime conditions for this band suffer from extreme D-layer
absorption, reducing the amount of signal to levels far below the noise
floor of our receivers. This limits daytime coverage to essentially
ground-wave coverage. At night, the D layer dissipates rapidly and worldwide
160-meter communication becomes possible via the F2-layer and in ducts in
the electron density valley above the E region peak. Depending on the
propagation mode, high or low elevation angles may be required. A limiting
factor is the noise levels prevalent at these frequencies, both atmospheric
and man-made as well as tropical and mid-latitude thunderstorms which cause
high levels of static in the summer season. Winter conditions are much
better, making winter evenings the best time to work 160-meter DX.

So you might have ground wave on 160M during the day to 100 miles or so.

See URL for details and formulas on ground wave distances
http://www.qsl.net/g3cwi/Downloads/Propagation%201.doc


As I sed --- way too much on propagation to put on a post and cover all the
variables and details -- the original poster needs to get a good book or at
least look at this free URL
http://www.ae4rv.com/tn/propflash.htm

And of course -- "on 10 meters at the
bottom of the sunspot cycle 10 is open nearly every day to
somewhere."


Sure -- ground wave and perhaps sporadic-E

--
The Anon Keyboard
I doubt, therefore I might be



"Bill Turner" wrote in message
...
On Sun, 28 Nov 2004 13:01:47 -0800, "Keyboard In The Wilderness"
wrote:

On 160M in the day time in the summer with low power -- you ain't going
anywhere


__________________________________________________ _______

This is true but not for the reason you might think. 160 meters has
excellent groundwave propagation; better than any other amateur band in
fact, but the lack of stations is the real reason 160 is mostly dead in
the daytime. It's a self fulfilling prophecy - nobody is on, so I'm not
going to get on either. The same thing happens on 10 meters at the
bottom of the sunspot cycle even though 10 is open nearly every day to
somewhere.

--
Bill W6WRT




Keyboard In The Wilderness November 28th 04 10:31 PM

Bill I agree But
The original poster sed:

"My very first contacts were established with 2 land stations on 14300 at
100W that were about 1000 miles away. They both reported that my signal
was good and that it sounded like I was "sitting right next to them". I
have no idea if this was a good distance, great, or mediocre."

So I assume he was after contacts of several hundred (thousand) miles - not
ground wave.

My point was this for the 160M band (From a book on propagation)

"160 meters. Daytime conditions for this band suffer from extreme D-layer
absorption, reducing the amount of signal to levels far below the noise
floor of our receivers. This limits daytime coverage to essentially
ground-wave coverage. At night, the D layer dissipates rapidly and worldwide
160-meter communication becomes possible via the F2-layer and in ducts in
the electron density valley above the E region peak. Depending on the
propagation mode, high or low elevation angles may be required. A limiting
factor is the noise levels prevalent at these frequencies, both atmospheric
and man-made as well as tropical and mid-latitude thunderstorms which cause
high levels of static in the summer season. Winter conditions are much
better, making winter evenings the best time to work 160-meter DX.

So you might have ground wave on 160M during the day to 100 miles or so.

See URL for details and formulas on ground wave distances
http://www.qsl.net/g3cwi/Downloads/Propagation%201.doc


As I sed --- way too much on propagation to put on a post and cover all the
variables and details -- the original poster needs to get a good book or at
least look at this free URL
http://www.ae4rv.com/tn/propflash.htm

And of course -- "on 10 meters at the
bottom of the sunspot cycle 10 is open nearly every day to
somewhere."


Sure -- ground wave and perhaps sporadic-E

--
The Anon Keyboard
I doubt, therefore I might be



"Bill Turner" wrote in message
...
On Sun, 28 Nov 2004 13:01:47 -0800, "Keyboard In The Wilderness"
wrote:

On 160M in the day time in the summer with low power -- you ain't going
anywhere


__________________________________________________ _______

This is true but not for the reason you might think. 160 meters has
excellent groundwave propagation; better than any other amateur band in
fact, but the lack of stations is the real reason 160 is mostly dead in
the daytime. It's a self fulfilling prophecy - nobody is on, so I'm not
going to get on either. The same thing happens on 10 meters at the
bottom of the sunspot cycle even though 10 is open nearly every day to
somewhere.

--
Bill W6WRT




Keyboard In The Wilderness November 28th 04 10:36 PM

OOppps you are right -- I shouldn't have sed anywhere.
Of course ground wave may get out to 100 miles.

See my other post

--
The Anon Keyboard
I doubt, therefore I might be



"Bill Turner" wrote in message
...
On Sun, 28 Nov 2004 13:01:47 -0800, "Keyboard In The Wilderness"
wrote:

On 160M in the day time in the summer with low power -- you ain't going
anywhere


__________________________________________________ _______

This is true but not for the reason you might think. 160 meters has
excellent groundwave propagation; better than any other amateur band in
fact, but the lack of stations is the real reason 160 is mostly dead in
the daytime. It's a self fulfilling prophecy - nobody is on, so I'm not
going to get on either. The same thing happens on 10 meters at the
bottom of the sunspot cycle even though 10 is open nearly every day to
somewhere.

--
Bill W6WRT





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