[CQ-Contest] Which would make better stubs?

[Marty Woll]

I have made stubs from LMR-400, RG-213, RG-400 and RG-58 for various home and field applications over the years.  In general, they all work; the difference is in depth of the null and in the bandwidth of the null.  As W4EF pointed out, the lower-loss cables produce higher-Q traps; i.e., sharper, deeper nulls.  My RG-58 stubs attenuate the second harmonic by about 24 dB; the RG-213 stubs by about 29 dB; and the LMR-400 stubs by about 31 dB.

In Field Day, where no station is running more than 200 watts and there is some physical separation of antennas, the RG-58's are fine, and they're pretty easy to transport in a carrying bag.  At the Caltech station, where side-by-side KW stations feed yagis stacked on the same tower, I went with the LMR-400 for the extra 7 dB it provides.  Since they reside behind a desk, their greater bulk isn't an issue.

73,

Marty N6VI