|[AMRadio] new antenna and matchbox a bust.|
ars.w5omr at gmail.com
Mon Jan 29 17:21:15 EST 2007
Craig C. Heaton wrote:
> Shielding on the outside of the coax messes up the balance, short
> explanation. Ok, back to the original message, 50 feet on each side of a
> dipole is more than likely too short on 80 meters, Johnson matchboxes don't
> have the range.
I've been reading all of this and wondering why someone hasn't offered
the suggestion of 'adding' some length to the feedlines.
A 100' wide, flat-top dipole, fed with 50+ft of open-wire line, will
work on 75m, and work well. I've experienced it too many times.
> I mentioned a loop because it works on small city lots.
I've got a lot that's 120' deep x 60' wide. In that 120', I erected a
75m inverted vee, some years (10?) ago.
2 years ago, I removed the coax, and changed out to 450 ohm ladder line
(that 'windowed' black stuff).
It made a lot of difference.
A month later, I closed in the bottom of the 75m Inverted vee, and
created a 'delta loop'. I use ~around'ish~ another 120~140' of wire.
Now, the antenna is a Full Wave Delta Loop on 75m, fed with 450ohm
ladder line. It seems to be 'quieter', meaning there's a greater
signal-to-noise ratio. There's twice as much wire up there, so the
capture effect for signals is greater (I think Brett experienced
stronger signals, as well).
I've got neighbors all around me, and I have not heard any complaints,
in a couple of years.
(Then again, I don't wanna go around the neighborhood asking for WAN
73 = Best Regards,
-Geoff/W5OMR (home again)
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