Having seen the topic come up a few times in the last week, I think it's worth
reminding that there are numerous books/calculators out there for log-periodics
which can enable you to tailor a custom design to any frequency range or gain
target or size target that you want, within the limits of physics, and also
create something that is highly field-repairable which cannot always be said
for factory antennas.
For roving purposes I like the idea of keeping the simplicity of a single
antenna but still handling those unexpected "hey, do you have 220?" moments.
Faster set up, tear down, easier to transport and carry, less coax jumble to
worry about, no spacing constraints to worry about (and if they're ignored you
loose some EIRP and directionality anyway), etc. I've been working on a LPDA
for myself over the last couple weeks so hopefully we'll see in August whether
that effort was worthwhile.
At one point I considered trying to pack a couple common bands onto one yagi
boom, as has been attempted by the MFJ 1760 and a couple trapless HF antenna
designs. Not sure if anyone has perfected that approach, but I'd be curious to
hear of any promising experiments.
Patrick
KB8DGC
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