[CQ-Contest] Stubs

PAUL M. PLAYFORD aef8w at aztec.asu.edu
Fri Jun 19 10:29:31 EDT 1998

I used my Palomar R-X noise bridge to make the stubs for the 8Q7AA

I determined the desired transmit frequency, doubled it and trimmed the
stubs for minimum noise at that frequency.  

As a for instance.  We wanted to transmit of 14.005 MHz so I trimmed the
cable for minimum noise at 28.010 MHz.  Very sharp tuning and yielded
23 dB attenuation at 28.010.

I constructed 2 stubs for each band with the exception of 40 meters.
One for cw and the other for ssb.  The 40 meter cw and ssb were close
together so one stub did it for both.  

The material I used was RG-8X - mini 8/U type cable.  The lower the loss
cable you use the better attenuation you get.  

Then a 'T' connector on the output of the amplifier with one branch
feeding the stub and the other branch feeding the antenna. 

We also used Dunestar bandpass filters between the FT1000MP's and Alphas.

To minimize confusion I marked all stubs with the desired transmitting

de Paul

Paul Playford, W8AEF                      twisted pair:    602/580-0015
35639 North 3rd Street                    internet: aef8w at aztec.asu.edu
Phoenix, AZ  85027-7405          I'm retired - doing nothing IS my job!

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