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Can I tune 10,12, 15 and 17 $& 20 m?
Posted: Mon Apr 09, 2018 10:37 pm
by KC6NEN
I am trying to design a dipole with traps/loading coils for 160-10 m. Can I probably tune 10, 12, 15 M with the same length of wire?
Can I probably tune 17 and 20 meter with the one wire length?
This would save designing/building/ inserting 3 traps.
Re: Can I tune 10,12, 15 and 17 $& 20 m?
Posted: Tue Apr 10, 2018 2:03 pm
by k9yli
If you chart out the lengths you will see some multiples of length. 40 and 15 are related..
as are 10 and 20 or 40 and 80.
Simpler antenna would be a fan dipole. one feed point, multiple wires cut to length..
Plus a lot of weight for that many traps.. Think separate antennas.
An 40/80 trap dipole,(because later on even with multiple band beam, 160 /80/40 will still be wire antennas.)
Lots of planning before you start building these antennas..
Re: Can I tune 10,12, 15 and 17 $& 20 m?
Posted: Thu Jun 07, 2018 2:47 pm
by ku3x
Building and all band trap antenna is do-able. "Is it your best choice?" Probably not. You'll pretty much need a set of traps per band. With every trap you make the antenna shorter. Now you narrow the bandwidth per band. More traps, each band looses bandwidth. A tuner does not correct this problem.
You'll have SWR issues and with high SWR on coax you increase the losses. Again, a tuner does not correct this problem.
Your best choice for an all band antenna is to erect a flat top dipole, for the lowest band of operation and feed it with parallel feeders.
The parallel feeders should be terminated at the transmatch, commonly misnamed an antenna tuner.
Barry, KU3X
www.ku3x.net