KingCobra_CDX882,
The biggest 'problem' with using a tuner is that the feed line to the antenna may not be capable of withstanding the affects of a high SWR. If the feed line will handle the SWR, and while there is some degradation of the amount of power reaching the antenna, in general, the signal produced by the system is almost impossible to tell from the same antenna being used with very little SWR and no tuner. It's exactly the same thing as using a transformer to change the 120 volts out of the AC line to some other voltage needed. There will be some power used/disipated in the transformer, but not enough to make any big differences (and RF tuners/transformers are a bit more efficient than AC transformers).
The 'other' reason(s) for using a tuner sort of make up for what power you might loose in one. Such as you may only have room for one antenna, or the antenna you are using with the tuner is for a particular purpose which you don't wanna do without. Or, the tuner is cheaper than a "do everything" antenna ( <--- My Biggie!).
If you need to 'tune'/transform impedances to get rid of SWR the best place to do that 'tuning'/transforming is where the SWR is being caused, and that's the best place to put the 'tuner'/impedance matching network (variable or not). If the mismatch is at the antenna/feedline junction, that's where the tuner ought to be, if possible. Which isn't always possible. The next choice is putting the tuner where is IS possible to use it. That sometimes means changing the type of feedline used. That can be a big problem, or not, just depends on where the whole mess is to start with. A tuner and open-wire/ladder-line/parallel conductor feed line is sort of 'impossible' for a mobile, as if you didn't know that (depends a @#$$ of a lot on the size of the mobile - LOL). But, that sort of setup does work very well, no matter what the 'supposed' losses in the tuner are. Got documented evidence of that if you just have to have it (hope not cuz I have no idea where to find it right now, it's been a while).
Are tuners, ladder line, etc, the absolute bestest things to have? Of course not. But in some instances they certainly are. Don't like the idea of tuners? That's okay too. They are a viable option though...
- 'Doc
In case you couldn't tell, I love tuners and ladderline antennas. There have been very few things I've asked mine to do that it couldn't do. Maybe not the biggest signal on the band, but as long as I'm heard, I could care less. There were several people in the 'Sand Pile', and their families here, that sort of liked it too.
