[TowerTalk] 15 meter decoupler

[Trent and Lorraine]

"Three quarters of a wavelength is too long for DX work."

I do agree Dan but I am sure that a YJ0 location by the sea has about a 15
DB gain over anything, best dx on ten was oh6 !  

Cheers

Trent Sampson 
[PO Box 1647 Toowoomba Qld 4350]  VK4TI 
 

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Dan Zimmerman N3OX
Sent: Wednesday, 29 November 2006 12:50 AM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] 15 meter decoupler

>By adding roughly 2 metres to the base end, it becomes ¾ wavelength on 
>10 metres.

Three quarters of a wavelength is too long for DX work.  I know it's funny,
but 0.7wl is OK, 0.75WL has high angle lobes.

It probably doesn't matter much on 10m when the band is open, because the
band's going to be open long and loud, and even if most of your power is
going at an angle of 49 degrees (and into space), you're still going to have
enough at low angles to make plenty of contacts.
This is especially true over saltwater where the low angle lobe is going to
be quite strong, but you'd be stronger  with a shorter antenna.

The low angle response of a 3/4 wave vertical is down about 4dB from the
response of the slightly shorter vertical.

73,
Dan
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