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Author Topic: ladder line laying on the roof.  (Read 4394 times)
W5WSS
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Posts: 1783




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« Reply #15 on: February 08, 2013, 05:01:50 AM »

Thanks Mark,  You can run your line on the roof.

I would not run my line on the roof because it will not work as intended.

When half the flat portion of a balanced feedline is against any material then that side of the line's signal being transfered is attenuated during transmitting.

Receiving through that same line would not be.

3/2 wavelength with respect to what he and everyone else presses the hybrid vertical horizontal radiating G5rv antenna into multi band service.
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K5LXP
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« Reply #16 on: February 08, 2013, 06:28:55 AM »

When half the flat portion of a balanced feedline is against any material then that side of the line's signal being transfered is attenuated during transmitting.

100% agreement.  The issue of what's within a few line widths of the balanced line matters.  I wouldn't call that a "radiating feedline" per se, but rather it's a condition of having an EM field as an inherent property.

What I am referring to is the "vertical polarization component" many claim a G5RV to have due to "radiating feedline".  This is not possible unless something about the antenna is imbalanced.  Yes, there may be a small amount of common mode due to being immersed in the EM field of the antenna but it's not being "generated" by the feedline. 


> 3/2 wavelength with respect to what

The design frequency. 


>  he and everyone else presses the hybrid vertical horizontal radiating G5rv antenna into multi band service.

Right.  As has already been mentioned it's a 20M antenna and happens to "load up" on other bands.  If it meets ones expectation, then it's a "good" antenna.


Mark K5LXP
Albuquerque, NM


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KC4MOP
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Posts: 764




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« Reply #17 on: February 08, 2013, 07:12:04 AM »

There's a lot of interesting myth and magic about the G5RV antenna.

Fred
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W5WSS
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Posts: 1783




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« Reply #18 on: February 08, 2013, 11:08:25 AM »

Mark, Ok fb, I did not comment about 20m being the design band. I am not commenting on the z match impedance,But just because I chose not to doesn't mean I didn't already know that. I am in agreement that a line will radiate when balance has been disturbed preventing total radiation cancellation along the line and the G5rv system radiation is a variation not all inclusive to the two inverted legs but radiation by the two conductor wire that happens to be some orientation as it travels the route chosen by the installer to the rest of the antenna,

I would not route this kind of Feed line over a roof. That defeats the now understood purpose that accompanies the design.

 Especially for feeding a G5rv since radiation from the feedline happens to be following and escaping via the orientation of the two conductors that are radiating some of the applied power rather than delivering all their package to the inverted legs is wanted.

Knowing these things we may minimize our destructive techniques to those parts of the system and attempt to better control the whole system balance which effects the antenna pattern, with proper installation techniques we can achieve what modeling suggests the antenna's capability.

End 73
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N0XE
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Posts: 197




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« Reply #19 on: February 17, 2013, 06:15:55 AM »

There is all this great theory and then there is reality, as some have stated put it up and see.  I have been to several Qrp Field Day sites were we ran the ladder Line on the ground and even coiled yet with an Elecraft K-2 at 15 watts we worked nearly ever station we could hear and we filled the logs,  you may be worrying about nothing.  Good luck, playing with antennas is a main part of the hobby, it can be a lot of fun and what works for you might not work for me,  you never know until you try,   73 Jim N0XE
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