On 9/22/2011 1:31 PM, Alex Malyava wrote:
> I need an advice for low band antenna (80-40) which does not need good
> grounding system.
You are paying far too much attention to impedance measurements. First,
you should be using an antenna tuner to match the antenna to the rig.
Second, you are expecting far too much from 100W on 80M. 559 is a great
report for a path on the order of 3,000-4,000 miles on 80M, especially
this time of year. I worked the NA Sprint last weekend, and was just
barely making 75M contacts to GA and New England with 1kW on both ends
and my dipole at 110 ft from my QTH in CA. That's a 2,500 mile path. We
made contacts ONLY because there were very good operators on both ends.
As to your antenna -- if you want to use it only on 80/75M, try for a
length of about 65 ft, and try to make the radials about 25% shorter
than that. If you also want to use it on 160M, try to make it about
90-100 ft, and make the radials as long as you can. You WILL need an
antenna tuner, but if your rig has one built in, it will probably load
it just fine.
73, Jim K9YC
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