I know nothing about that particular "matcher", but can give you an educated guess about how useful it will be. You won't like what I have to say about it though.
that particular 'matcher' is just too small to do much 'matching' (impedance matching). There are, or can be, some fairly hefty voltages produced during impedance matching. That usually means that the components used in that 'matcher' are going to be larger than will fit in that small of a package if the impedances are not very 'close' to right. If it's used in conjunction with the matching device on the antenna, you may be able to make things decent over a fairly wide range of frequencies. But that means adjusting the antenna it's self, which is what you're trying to get away from, right? Just not too practical in general. "WG" is also right about the power handling ability of that thing, don't expect much at all in that regard.
Tuners/matchers are useful, but they have to be of a reasonable 'size' to be really useful. They do not affect the antenna's state of tune at all, they only match the radio's impedance to the antenna system's impedance. Think of them as a variable impedance transformer, sort of like a variable voltage transformer. They can make some fairly unsuitable antennas 'usable', but they are not going to make them 'suitable' (if that makes sense).
- 'Doc
(Save that knob and throw the rest away.)
