It is hard to debate and discuss typing with one thumb onto a cell phone.
At field day we use a tri-plexers to drive a trip band yagis and have found the
use of coaxial stubs to be extremely helpful. Long before W2VJN's NCJ article I
was doing exactly what he recommended. I use exclusively double 1/4 wavelength
shorted stub networks with a 1/6 wavelength coupling cable between the two
stubs.
I have gotten into the practice of fabricating 1/8 & 1/4 wave coax cables 2
each of each type for every stub network.
A 20 to 30 ft long coax cable is placed between each tri-plexer port and the
stub networks. We then add the other cables as needed for our field day
deployment. Our standard setup is a 20M stub network on the 20M port of the
tri-plexer to prevent 2nd harmonic overload on 10M. On 15M we use a 40M stub
network to null 20 & 10 meters. The 40M network will pass 15M with minimal
insertion loss. The 10M tri-plexer port is driven directly if the band is open.
This arrangement has allowed us to use of medium grade radios with dynamic
ranges in the 70's to 80's. I myself have had outstanding success using my Omni
6 with the 500hz INRAD filter mod.
This year for field day we will be using Elecraft KX3's and making a run at 2A
qrp from a secret mountain top in EWA. We just scouted the QTH on Friday it has
a 3,000 foot drop off to the SE - NE. You look down to the horizon. We are
very excited. This year our callsign will be W7TST 2A EWA. (maybe 3A)
73, Don KO7I
Sent from my Verizon Wireless 4G LTE smartphone
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