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Old May 15th 08, 06:51 AM posted to rec.radio.shortwave,alt.radio.shortwave
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Posts: 2,056
Default Dual connection to same antenna

Telamon wrote:

Instead of just disconnecting the radio and ground you might also want
to connect the coax center conductor and shield together at that switch
point.


After giving this some thought, I got to wondering...

The induced voltage in the antenna has an instantaneous vector value.
Same on the outer sheathing of the coax. When the signal in the sheath
is redirected to the inner conductor, it will, in effect, be changing
direction.

That changed direction will be in opposition to the signal in the main
antenna wire.

I'm thinking that the length of the coax will in effect be subtracted
from the antenna length, not added as I had previously thought.

The antenna, apparently, is only as long as the wire portion MINUS the
coax length.

This is all assuming that the switch is indoors, at the very end of the
coax, not where the antenna joins the inner conductor.


mike



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Old May 16th 08, 02:19 AM posted to rec.radio.shortwave,alt.radio.shortwave
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First recorded activity by RadioBanter: Jul 2006
Posts: 4,495
Default Dual connection to same antenna

In article [email protected], m II wrote:

Telamon wrote:

Instead of just disconnecting the radio and ground you might also want
to connect the coax center conductor and shield together at that switch
point.


After giving this some thought, I got to wondering...

The induced voltage in the antenna has an instantaneous vector value.
Same on the outer sheathing of the coax. When the signal in the sheath
is redirected to the inner conductor, it will, in effect, be changing
direction.

That changed direction will be in opposition to the signal in the main
antenna wire.


Maybe. At some frequencies it will sum in opposition but not at all
frequencies.

I'm thinking that the length of the coax will in effect be subtracted
from the antenna length, not added as I had previously thought.

The antenna, apparently, is only as long as the wire portion MINUS the
coax length.

This is all assuming that the switch is indoors, at the very end of the
coax, not where the antenna joins the inner conductor.


I suggested that you short the outer and inner coax conductor so the
wire and coax would function common mode. Essentially the coax would
just make the wire part look longer.

--
Telamon
Ventura, California
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Old May 16th 08, 03:06 AM posted to rec.radio.shortwave
RHF RHF is offline
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Posts: 8,676
Default Dual connection to same antenna

On May 15, 6:19*pm, Telamon
wrote:
In article [email protected], m II wrote:
Telamon wrote:


Instead of just disconnecting the radio and ground you might also want
to connect the coax center conductor and shield together at that switch
point.


After giving this some thought, I got to wondering...


The induced voltage in the antenna has an instantaneous vector value.
Same on the outer sheathing of the coax. When the signal in the sheath
is redirected to the inner conductor, it will, in effect, be changing
direction.


That changed direction will be in opposition to the signal in the main
antenna wire.


Maybe. At some frequencies it will sum in opposition but not at all
frequencies.

I'm thinking that the length of the coax will in effect be subtracted
from the antenna length, not added as I had previously thought.


The antenna, apparently, is only as long as the wire portion MINUS the
coax length.


This is all assuming that the switch is indoors, at the very end of the
coax, not where the antenna joins the inner conductor.


- I suggested that you short the outer and inner coax conductor
- so the wire and coax would function common mode.
-
- Essentially the coax would just make the wire part look longer.
-
- --
- Telamon
- Ventura, California

House -o======------------------------------======x

x======-------------------------------======o- Shop

-o PL-259 Plug
= Coax Cable
- Antenna Wire
x Shorted End

OK that works ~ RHF

-but- It brings the 'common-mode' noise from the
House to the Shop and the Shop to the House.
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Old May 16th 08, 11:55 PM posted to rec.radio.shortwave
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First recorded activity by RadioBanter: Jul 2006
Posts: 4,495
Default Dual connection to same antenna

In article
,
RHF wrote:

On May 15, 6:19*pm, Telamon
wrote:
In article [email protected], m II wrote:
Telamon wrote:


Instead of just disconnecting the radio and ground you might also want
to connect the coax center conductor and shield together at that switch
point.


After giving this some thought, I got to wondering...


The induced voltage in the antenna has an instantaneous vector value.
Same on the outer sheathing of the coax. When the signal in the sheath
is redirected to the inner conductor, it will, in effect, be changing
direction.


That changed direction will be in opposition to the signal in the main
antenna wire.


Maybe. At some frequencies it will sum in opposition but not at all
frequencies.

I'm thinking that the length of the coax will in effect be subtracted
from the antenna length, not added as I had previously thought.


The antenna, apparently, is only as long as the wire portion MINUS the
coax length.


This is all assuming that the switch is indoors, at the very end of the
coax, not where the antenna joins the inner conductor.


- I suggested that you short the outer and inner coax conductor
- so the wire and coax would function common mode.
-
- Essentially the coax would just make the wire part look longer.
-

House -o======------------------------------======x

x======-------------------------------======o- Shop

-o PL-259 Plug
= Coax Cable
- Antenna Wire
x Shorted End

OK that works ~ RHF

-but- It brings the 'common-mode' noise from the
House to the Shop and the Shop to the House.
.


If he is not in his house to make the electrical noise then there should
not be a problem right? What do you say to that Mr. Logic Person?

--
Telamon
Ventura, California
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Old May 17th 08, 12:18 AM posted to rec.radio.shortwave
RHF RHF is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 8,676
Default Dual connection to same antenna

On May 16, 3:55*pm, Telamon
wrote:
In article
,





*RHF wrote:
On May 15, 6:19*pm, Telamon
wrote:
In article [email protected], m II wrote:
Telamon wrote:


Instead of just disconnecting the radio and ground you might also want
to connect the coax center conductor and shield together at that switch
point.


After giving this some thought, I got to wondering...


The induced voltage in the antenna has an instantaneous vector value..
Same on the outer sheathing of the coax. When the signal in the sheath
is redirected to the inner conductor, it will, in effect, be changing
direction.


That changed direction will be in opposition to the signal in the main
antenna wire.


Maybe. At some frequencies it will sum in opposition but not at all
frequencies.


I'm thinking that the length of the coax will in effect be subtracted
from the antenna length, not added as I had previously thought.


The antenna, apparently, is only as long as the wire portion MINUS the
coax length.


This is all assuming that the switch is indoors, at the very end of the
coax, not where the antenna joins the inner conductor.


- I suggested that you short the outer and inner coax conductor
- so the wire and coax would function common mode.
-
- Essentially the coax would just make the wire part look longer.
-


House -o======------------------------------======x


x======-------------------------------======o- Shop


-o PL-259 Plug
= Coax Cable
- Antenna Wire
x Shorted End


OK that works ~ RHF


-but- It brings the 'common-mode' noise from the
House to the Shop and the Shop to the House.
*.


- If he is not in his house to make the electrical noise
- then there should not be a problem right?
-
- What do you say to that Mr. Logic Person?
-
- --
- Telamon
- Ventura, California

Telamon,

Houses are filed with . . .

'other' People {Family Members

Who each use Electrical Items

that Generate RFI and EMF Noise Artifacts

PLUS - The ever present Stand-by-Mode

and Ready-On / Instant-On Devices

that Populate Every Home

each with it's own unique Electronic Signature.

Telamon - NO LOGIC REQUIRED :

It's Just Plain Common Sense. ~ RHF


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Old May 17th 08, 03:08 AM posted to rec.radio.shortwave
RHF RHF is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 8,676
Default Dual connection to same antenna

On May 16, 5:08*pm, m II wrote:
RHF wrote:
It's Just Plain Common Sense. ~ RHF


- I DID say that if I'm not in the house, there's no noise.

How Do You Prove A Negative ?

- Even the computer gets switched right off with a real
- switch..not that software only thing at the front of the case.

This is very Revealing About You
and the Way You 'choose' to Exist
in your very 'private' Abode.

- The clocks and fridge are the only things running
- and produce no noticeable noise.
-
- mike

I Hear Clocks Going Tick-Tock All Through The Night

Time is Alive and as . . . Noisy As Hell ! ~ RHF
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Old May 17th 08, 03:28 AM posted to rec.radio.shortwave
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First recorded activity by RadioBanter: Jul 2006
Posts: 2,056
Default Dual connection to same antenna

RHF wrote:

- I DID say that if I'm not in the house, there's no noise.

How Do You Prove A Negative ?


By showing that the converse IS true. When I AM in the house, there IS
noise. As I shut off the things I use, the noise subsides to nothing. I
am assuming there is no electronic anarchy going on after I close the
door behind me.



- Even the computer gets switched right off with a real
- switch..not that software only thing at the front of the case.

This is very Revealing About You
and the Way You 'choose' to Exist
in your very 'private' Abode.


So true. The local hermits seek me out for advice.


I Hear Clocks Going Tick-Tock All Through The Night

Time is Alive and as . . . Noisy As Hell ! ~ RHF


I love those old Grandfather clocks. It's really unfortunate about those
heavy, sharp edged pendulums. They're just SO easy to swing around
during the Festivities..who knew it would cut more than turkey?

I'm out now, that's all that counts...that and the restraining order...



mike

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Old May 17th 08, 03:37 AM posted to rec.radio.shortwave
RHF RHF is offline
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First recorded activity by RadioBanter: Jun 2006
Posts: 8,676
Default Dual connection to same antenna

On May 16, 7:28*pm, m II wrote:
RHF wrote:
- I DID say that if I'm not in the house, there's no noise.


How Do You Prove A Negative ?


By showing that the converse IS true. When I AM in the house, there IS
noise. As I shut off the things I use, the noise subsides to nothing. I
am assuming there is no electronic anarchy going on after I close the
door behind me.

- Even the computer gets switched right off with a real
- switch..not that software only thing at the front of the case.


This is very Revealing About You
and the Way You 'choose' to Exist
in your very 'private' Abode.


So true. The local hermits seek me out for advice.


The Local Hermits and I Commuicate : The Silence Unites Us

bringing understanding without words ~ RHF


I Hear Clocks Going Tick-Tock All Through The Night


Time is Alive and as . . . Noisy As Hell ! ~ RHF


I love those old Grandfather clocks. It's really unfortunate about those
heavy, sharp edged pendulums. They're just SO easy to swing around
during the Festivities..who knew it would cut more than turkey?

I'm out now, that's all that counts...that and the restraining order...

mike


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Old May 17th 08, 06:30 AM posted to rec.radio.shortwave
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First recorded activity by RadioBanter: Jul 2006
Posts: 4,495
Default Dual connection to same antenna

In article
,
RHF wrote:

On May 16, 3:55*pm, Telamon
wrote:
In article
,





*RHF wrote:
On May 15, 6:19*pm, Telamon
wrote:
In article [email protected], m II wrote:
Telamon wrote:


Instead of just disconnecting the radio and ground you might also
want
to connect the coax center conductor and shield together at that
switch
point.


After giving this some thought, I got to wondering...


The induced voltage in the antenna has an instantaneous vector value.
Same on the outer sheathing of the coax. When the signal in the
sheath
is redirected to the inner conductor, it will, in effect, be changing
direction.


That changed direction will be in opposition to the signal in the
main
antenna wire.


Maybe. At some frequencies it will sum in opposition but not at all
frequencies.


I'm thinking that the length of the coax will in effect be subtracted
from the antenna length, not added as I had previously thought.


The antenna, apparently, is only as long as the wire portion MINUS
the
coax length.


This is all assuming that the switch is indoors, at the very end of
the
coax, not where the antenna joins the inner conductor.


- I suggested that you short the outer and inner coax conductor
- so the wire and coax would function common mode.
-
- Essentially the coax would just make the wire part look longer.
-


House -o======------------------------------======x


x======-------------------------------======o- Shop


-o PL-259 Plug
= Coax Cable
- Antenna Wire
x Shorted End


OK that works ~ RHF


-but- It brings the 'common-mode' noise from the
House to the Shop and the Shop to the House.
*.


- If he is not in his house to make the electrical noise
- then there should not be a problem right?
-
- What do you say to that Mr. Logic Person?
-

Telamon,

Houses are filed with . . .

'other' People {Family Members


How do you know he lives with other people?

Who each use Electrical Items

that Generate RFI and EMF Noise Artifacts


If he does live with other people he asks them to keep the noise makers
turned off.

PLUS - The ever present Stand-by-Mode

and Ready-On / Instant-On Devices


You turn them off or unplug them.

that Populate Every Home

each with it's own unique Electronic Signature.

Telamon - NO LOGIC REQUIRED :


I require logic.

It's Just Plain Common Sense. ~ RHF
.


Your common sense is nonsense.

--
Telamon
Ventura, California
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Old June 21st 18, 08:03 AM posted to rec.radio.shortwave,alt.radio.shortwave
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First recorded activity by RadioBanter: May 2016
Posts: 6
Default Dual connection to same antenna

m II writes:

Telamon wrote:

Instead of just disconnecting the radio and ground you might also want
to connect the coax center conductor and shield together at that switch
point.



The induced voltage in the antenna has an instantaneous vector value.
Same on the outer sheathing of the coax. When the signal in the sheath
is redirected to the inner conductor, it will, in effect, be changing
direction.

Have your tried reading "Transmission Line Transformer Book" by Jerry Sevick? I was able to get a copy from a local library using their loan program! They actually found a copy. It is very interesting.

I have been wanting to read ``Theory and practical designs for the experimenter'' By Jerry Sevick, W2FMI. 115 pages. It is hard to come by these books. Also the materials listed in the books are not your standard amidon mix#. Getting baluns to work would probably necessitate a nice signal generator, and hopefully spectral analyzer, to say the least.

I do have a circuit for measuring forward and reflected radio waves - unfortunately I do not have a shielded enclosure to attach the two metters... It's still laying on some copper clad ...

[ ... damn... ] I was going to scan the schematic but the scanner is complaining about windows 7 missing some kind of internet fax twain device. A wireless fax machine. So new and inventive.

Anycase; Bill Hickox, K5BDZ ``only an swr meter''. I should take head and advise myself it is probably better to buy a professional SWR meter, but I can't even find a damn aluminium box... Autocenter meters - try dans small parts...

That changed direction will be in opposition to the signal in the main
antenna wire.

reflected swr.

I'm thinking that the length of the coax will in effect be subtracted
from the antenna length, not added as I had previously thought.

watch for standing waves.

The antenna, apparently, is only as long as the wire portion MINUS the
coax length.

velocity factors as well.

This is all assuming that the switch is indoors, at the very end of the
coax, not where the antenna joins the inner conductor.

yeah like finding radio grade coax that hasn't been cut to pieces by comcast yet.


mike

steve


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