Where to make the thing resonant? Depends, sort of. If you only use one particular portion of a band, make it resonant there. If you use the whole band, sort of 'aim' for the center of the band. If you only use one particular frequency on a band, then there. And so on and so on...
There are really two steps in tuning an antenna. Making it resonant, and matching it's input impedance to the feed line/transmitter, usually about 50 ohms. The resonant thingy isn't too difficult, just make the thing the right length, sort of. Impedance matching can be sort of 'hairy'. Not really all that bad, but mostly not 'right' as it comes "out of the box".
SWR is an almost useless measurement with the common SWR meter, which doesn't really tell you much specifically. It will tell you if the whole antenna system is close to what it ought to be, sort of, but there are a number of instances when it ain't right at all. A simple SWR meter just isn't very smart. It is very useful to tell when things change!
Does that mean you shouldn't use one? No, just be aware that you have to be smarter than that meter to tell if things are 'right' or not. Which isn't always 'fool-proof'.
- 'Doc
Ain't nothing 'perfect' unless you throw unbelievable amount of money at it... each time things change.
