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Exterminator circular?

 
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Exterminator circular?
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gkramer
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Joined: 12 Sep 2008
Posts: 3

Post Exterminator circular? Reply with quote
Does any one know how to make te Exterminator antenna circular? Does any one
have the specs for this. There are examples on the internet. You can find it with
Google
Fri Sep 12, 2008 3:46 pm View user's profile Send private message
Dreammachine-Radio
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Joined: 19 Feb 2008
Posts: 35
Location: Lowlands
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Post Re: Exterminator circular? Reply with quote
gkramer wrote:
Does any one know how to make te Exterminator antenna circular? Does any one
have the specs for this. There are examples on the internet. You can find it with
Google


No not iam aware of, but why dont by one compleet?
Wed Sep 17, 2008 9:12 am View user's profile Send private message Visit poster's website
gkramer
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Joined: 12 Sep 2008
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They are not sold any more. That's is why. It isn't easy to make them, is the reason
from the manufacturer
Wed Sep 17, 2008 5:16 pm View user's profile Send private message
intertech
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Joined: 15 Mar 2006
Posts: 24
Location: Chicago USA

Post Reply with quote
Hello gkramer,

Your question is one of polarization and we assume you would "like" the Exterminator to be circular. This is interesting because a CP antenna is probably the "biggest" FM marketing gimmick of all time.

The question of polarization for FM is confusing. once upon a time horizontal polarization was the "in thing". then vertical became flavor of the month thanks to those whip antenna's on motor vehicles. but both had to be served so the FCC authorized the use of "supplemental vertically polarized effective radiated power" enter the big con "circular" which presumably meant that equal amounts of horizontal and vertical polarized energy are radiated.

Rather than bore you with reams of scientific mumbo jumbo from an engineering rationale, vertical polarization is best. (several papers are available on the internet written by very smart intelligent folk that know about these issues)

Further we have conducted highly successful results using vertical polarization. Our investigations displayed increases in signal levels that exceeded 5 dB when compared directly with an equivalent CP antenna. indeed there are many other advantages associated with vertical polarization such as zero interaction with tower structures, reduced interference, higher levels of rejection and so on.

BTW: The most gain you can squeeze out of a mono pole is .64 wave, going above this wavelength the antenna will exhibit pattern breakup due to extremely high angles of radiation, this is not news, in fact they figured this out back in 1930's! The inverted cone on the Exterminator acts as a 1/4 wave phase reversal sleeve, this interacts with the antenna's radiating 1/2 wave element, when energized you effectively have a 1/2 wave radiating over a radiating 1/4 wave which produces a more "flattened" donut pattern with the major lobe relatively horizontal at 30 and 45 degree up angle. By altering the antenna's mechanical points we "distorted" the wave to be equal to .64 wave thereby ensuring the highest dB gain possible.

As to availabilty I would like to direct those who think the antenna is not produced to visit PCS's antenna page, you will see the Exterminator is available for immediate delivery, there you can also review it's specifications.

To conclude, it is widely accepted that a CP antenna by its own design is a poor radiator. We have come across posts on various blogs that suggest the Exterminator is a CP type of radiator due to the inverted cone, although we can understand those authors thinking this is not the case. The exterminator is a Vertically Polarized Radiator.

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Fri Sep 19, 2008 12:37 am View user's profile Send private message Visit poster's website
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