[CQ-Contest] Coax Stubs...

[Douglas Ruz (CO8DM)]

Hi Dave,

Thanks for information about RG-6 cable...yes, it has foam insulation.

I have an old MFJ-259 ant analyzer...what do you suggest??...in the MFJ 
manual said i must add a 50 ohms carbon resistor in serie with stub...is it 
ok?

I think i can start with shortest stub 23 % longer than K2TR lenght...ok?

Any other idea is welcome.

TIA,

73....Douglas, CO8DM

"No creo que haya alguna emoción más intensa para un inventor que ver alguna 
de sus creaciones funcionando. Esa emoción hace que uno se olvide de comer, 
de dormir, de todo." - Nikola Tesla
----- Original Message ----- 
From: "Dave Hachadorian" <k6ll.dave at gmail.com>
To: "reflector cq-contest" <cq-contest at contesting.com>
Sent: Wednesday, January 13, 2016 5:49 PM
Subject: Re: [CQ-Contest] Coax Stubs...


I would use a regular TV-type male crimp connector for one end of
the stub, and then type F female to UHF male adapter:
http://www.showmecables.com/product/F-Type-Female-to-UHF-Male-Adapter.aspx?utm_source=google&utm_medium=cse&utm_campaign=925&zmam=49733141&zmac=5&zmas=1&zmap=925&gclid=CKaEu8ntp8oCFYaCfgodkwABjw

If you need a shorted stub, you can use a wire nut at the other
end:
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwibgICJ7qfKAhXB4CYKHR4OAh0QjRwIBw&url=http%3A%2F%2Fwww.idealind.com%2FprodDetail.do%3FprodId%3Dwire-nut&psig=AFQjCNFEGVnkoG8vDszegO6oyMAI4hz0Cw&ust=1452811320423462

RG-6 has wide variation in velocity factor, so you need to use a
dip oscillator, or some other instrument to measure the resonant
frequency of the stub.  If your RG-6 has foam insulation, your
stubs will need to be roughly 23% longer than the K2TR lengths
shown here:
http://www.k1ttt.net/technote/k2trstub.html
You really need to measure the resonant frequency though, rather
than just cutting to length.


Dave Hachadorian, K6LL
Yuma, AZ