Rick - DJ0IP / NJ0IP wrote:
Frank,
Had a good laugh at your last sentence.
Now take any antenna resonating on 80m.
What's your SWR at 3.500 MHz? 3.800 MHz? 4.000 MHz?
I don't know a reasonable antenna that is under 2:1 across this range.
In fact most will rise to 4:1 or higher.
I had my blinders on thinking about 20 meters and up. 80 meters is a
problem but there is a solution for those who need to cover the entire
band. Folded dipole cut for the lower middle of the band and a closely
spaced parasitic wire cut for the higher end of the band. I used such
an antenna a few years back and was able to cover both the high end of
75 and 80 CW with less than 1.5:1 SWR. Of course a folded dipole
sporting a parasitic wire is not exactly inconspicuous.
Also, I have a peculiar situation of having lots of space, about 2 acres,
but am renting and the owner lives in the other half of the house. We
negotiated permission for ONE ANTENNA before I signed the lease. He
wanted it as far out of site and inconspicuous as possible.
Again, appologies for my blinders. Being beholding to an unsympathetic
landlord is the pits.
With one antenna and wanting to work all bands, I would normally use
openwire to feed an 80m dipole.
Openwire is out of the question because it is highly conspicuous.
I put up a special OCF Dipole (just one radiator, not multiple) which covers
80, 40, 30, 20, 15, 12, and 10m. 7 bands with just one antenna, fed with
about 100' of LMR-240. The SWR is fairly good on all bands, being as high
as 3.5:1 (worst case) on one band and averaging 2:1 on most bands. Not
exactly the perfect antenna, but it gets the job done on all of these bands.
I don't know of any other antenna fed with coax that can give an acceptable
match on all of these bands.
THEREFORE, I am quite happy to use the built-in ATU in my Eagle (or Jupiter,
or Orion, etc.), even though in a perfect world, this would not be my
antenna of choice and I would not want to have to use a tuner.
I'm taking about reality, not virtual reality! :-)
Your reality is a little different from mine. I have lots of antennas,
no landloerd, and understanding neighbors. I did live in an appartment
many decades ago. At that time my hamming was done as a mobile.
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