>
> My question : - Is it better to try and achieve the lowest SWR (peferable at
> the end of the 70 ohm ladder line as this becomes part of the antenna) and
> then rely on the ATU (as I do) or is my friend correct to go the easy way.
>
>
>
Using a combination of ladder line and coax lengths the give impedances
which can be matched by your ATU will be more convenient, but likely
more lossy that just using ladder line all the way to a wider impedance
range capable balanced tuner. The best way, as far a transmit power
efficiency goes, will be to keep the high SWR on the ladder line, and
not in the coax. Put the tuner between the ladder line and the coax, and
keep the SWR on the coax to 1:1 by adjusting the tuner. This will not be
as convenient, because you will need a tuner you may not own yet, and
when you get one it will likely not be automatic or it will be fairly
expensive.
Remember, the most convenient all band load for your transceiver is a 50
ohm non-inductive resistor. You get a 1:1 SWR on all bands with no
adjustments needed when you change bands. This setup is a bit
inefficient in terms of RF field generated versus RF power generated by
your transmitter. Antennas that are similarly convenient for multiple
band use are often similarly inefficient.
DE N6KB
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|