HF VHF UHF LOG PERIODIC 20 TO 1.2 GHZ
 

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Nice!

What is the feedline coax and how old is it?

73,
Chip N1IR

Maybe once you have sold it you might be willing to post the plans for the
antenna??
Sorry I am unable to bid on it, cost for shipping is too high.

Kevin ZL1UDD

"Fumper" wrote in message
...
SEE THIS ON EBAY
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Must be interesting as the rear elements start approaching
odd-multiples of the wavelength of the operating frequency..


"Kevin & Natalia Mitchell" wrote in message
...
Maybe once you have sold it you might be willing to post the plans for the
antenna??
Sorry I am unable to bid on it, cost for shipping is too high.

Kevin ZL1UDD

"Fumper" wrote in message
...
SEE THIS ON EBAY
http://cgi.ebay.com/ws/eBayISAPI.dll...tem=2244030632

Must be interesting as the rear elements start approaching
odd-multiples of the wavelength of the operating frequency..


Many ways to deal with this. Shorting is one.

73,
Chip N1IR

Uncle Peter wrote:

Must be interesting as the rear elements start approaching
odd-multiples of the wavelength of the operating frequency..



LPs don't care!!

They are a driven array and fed from the shortest wavelength. So, as the
active region becomes resonant the RF Power is radiated by the active
region. The portion of the energy that 'sneaks by' the active region is
negligible.

Check the Tennadyne site: http://www.tennadyne.com and the ARRL
Antenna Handbook.

LPs don't care!!

They are a driven array and fed from the shortest wavelength. So, as the
active region becomes resonant the RF Power is radiated by the active
region. The portion of the energy that 'sneaks by' the active region is
negligible.

Check the Tennadyne site: http://www.tennadyne.com and the ARRL
Antenna Handbook.


Actually Dave, it is a problem in some LPDA's:-). The self scaling of the
active region can degrade without a fix on some designs. Most commercial
LPDA's, such as the itty bitty WLAN LPDA's, have an inductive via as a short
to stop the back-resonance.

I'm sure they talk about this in one of the Antenna Compendiums. I can recall
the discussion but not the volume.


73,
Chip N1IR