[CQ-Contest] Coax Stubs with Tribanders

[Dave Hachadorian]

----- Original Message ----- 
From: "Filipe Lopes" <ct1ilt at mail.telepac.pt>
To: <cq-contest at contesting.com>
Sent: Friday, November 09, 2007 9:48 PM
Subject: Re: [CQ-Contest] Coax Stubs with Tribanders


> Hi,
>
> Can anyone help me with some scheme/measurements for stubs 
> using tribanders?
>
> I have 2 towers with tribander and 3 elem quad but they 
> are very close and I
> have some interference in some directions. Anyone can help 
> me ?
>
>
> I would like to try the stubs for CQWW CW...
-----------------------------

Here is a trick that not many people know about.

A 1/4 wave shorted 40 meter stub:
passes 40
rejects 20
passes 15
rejects 10

A 1/4 wave open 40 meter stub:
rejects 40
passes 20
rejects 15
passes 10

With these two stubs, you can operate on any two adjacent 
bands, 40 through 10. You can either move the stubs as 
required, or just put a shorting switch or relay at the ends 
to change from open to shorted.

1/4 wave stub for 7.020:
(246/7.02)*velocity factor of coax
for vf=.66 coax, the length is 23.1 feet (7.05 meters)


Dave Hachadorian, K6LL
Yuma, AZ





























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