Richard (Rick) Karlquist wrote:
> HansLG@aol.com wrote:
>> Hi there,
>>
>> Wasn't there a way with "bazooka" antenna to get a wider bandwidth of any
>> antenna? I will remember that you could use a parallel resonator to extend
>> the
>> bandwidth on any antenna. An other way was to have a "return" parallel with
>
> There were some articles in QST 20 or 30 years ago about using lumped
> element networks to broadband a dipole. You can get a mediocre match
> from 3.5 to 4 MHz using these. I think it stays under 2:1, but never
> gets better than 1.5:1. That may very well work OK for many users. The
> same technique could be used for a vertical of course. Much more
> effective that making the diameter larger. Probably isn't going to work
> for a 4 square, because it will screw up the phasing.
You might (might be the operative word here) be able to come up with a
multisection matching network that has reasonably low loss to cover the
3.5 to 4 (think of having two masts of the required length a couple feet
apart.. you get a sort of W shaped SWR curve)
And once you have that, you might be able to come up with a phasing
network that is also broadband and matches whatever weird impedances
you'll see on the elements. It will almost certainly have multiple
sections too.
Getting low loss would be a challenge with all those inductors and
capacitors.
A lot easier to just throw in some relays to change among fixed
networks, I suspect.
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