I'm pretty sure those are wrong. They are not impedance transformers but "matching pads." That sounds like the same thing but it's not. What these do, if I'm not mistaken, is add resistance to change a load impedance -- that is, if you've got a 75 ohm source and you want to drive a 50 ohm load, you put one of these in line. The problem is that you don't want to change a load impedance--you want to alter the characteristic impedance of the line, and a line isn't like a load. Load impedance is about the characteristics of the circuit being driven by the signal; characteristic impedance of a transmission line is a matter of matching the effects of inductance and capacitance to the load impedance so that there isn't a lot of return loss along the way from the source to the load. I don't know how clear that is -- what I am trying to say is that adding 25 ohms resistance to a 50 ohm coax doesn't alter the line impedance, but only the load impedance, and that does you no good. Additionally, you'll see (and this is related to what I'm saying above) that the insertion loss on these is immense-- 5.7 dB. What you want is an impedance transformer, which will have nothing but a core and windings inside, no attenuator.
Now, you may find, in ham radio sources and such-like, some transformer designs that are nothing but lengths of tuned coax--that won't work because you're handling a very, very broad band of frequencies so you cannot use a tuned transformer, which will only work within the narrow band for which it is tuned. You need a proper transformer, which is probably going to be not much more than a toroidal core with a few windings of wire around it. This is the sort of thing:
Impedance Matching Transformers from JFW Industries
Note, among other things, that it is a "transformer" rather than a "pad" and that the insertion loss is under a dB. But I have no idea of pricing or where you'd buy--you might need to go to a big electronic parts dealer like Mouser for these. Also, I note that on at least the one I looked at, the "stop frequency" is 600 MHz so I'm not sure how high up these are guaranteed to work (though most CATV stuff is so badly made, and these are probably much nicer, so that even when these work badly they may work quite well for CATV).
I hope this helps. I'm not sure what the cost of this sort of thing is likely to be, but there certainly is some argument, given the difficulty of replacement, for giving it a try.
Kurt
Blue Jeans Cable
P.S. Edit: Now that I look again, I see that I missed the fact that some of these go up to 2.2 GHz. You probably don't need that, but 1 GHz or 1.2 might be advisable in a digital cable system.
