wb2vuf at gti.net
Sun Feb 1 16:01:30 EST 2009
There is one design that I saw that uses ladder line and no tuner. It
uses a series of switches to switch in different lengths of 450 ohm line
to achieve a good match to coax through a 1:1 choke balun. It's clever,
but just as easy to use a tuner instead, in my opinion. Check it out at:
Ken Brown wrote:
> Hi Al,
> You said:
>> The advantage of a
>> simple dipole, resonant length or not, fed open line is a perfect 1:1 on
>> any frequency on any band and you don't have to use coax anywhere.
> This may be true for a few particular frequencies, with each dipole
> length/feed line impedance/feed line length combination you may try. And
> you could modify the lengths to make it true on some different
> frequencies. It is not true that there is a perfect 1:1 SWR "on any
> frequency on any band" for one dipole wire length and one open wire feed
> line length combination, even if you mean the SWR the transmitter sees
> and not the SWR on the line itself.
> With a matching network, it can be made to be nearly true, or at least
> appear to the transmitter to be true, by adjusting the matching network
> for each frequency, or perhaps bypassing it on those few special
> frequencies where you don't need it. You'll probably be using coax
> somewhere, like between the matching network and the transmitter, unless
> your transmitter has a link coupled output to feed open wire feed line
>>> Huh? A perfect 1:1 what? Not SWR
>> It wasn't clear but I meant a perfect 1:1 swr looking from the transmitter.
>> Not on the line itself. The line has a high swr on some bands but the loss
>> is minimal compared at any other type of feedline arrangement.
> DE N6KB
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