In article ,
Alan WA4SCA wrote:

I have and use several MFJ products. Design is ok to good, quality
control is marginal. Think of them as kits assembled by trainees with
no supervision. Be prepared to fix the cold solder connections,
poorly drilled mounting holes, etc. Once you finish that, they work
well and if treated carefully last.

The "treated carefully" is good advice - understanding the limitations
of the equipment is critical (and not specific to MFJ products!).

There are a number of stories going around, concerning people who have
managed to damage MFJ antenna tuners - typically, by burning up the
inductor (sometimes melting the form on which it's wound). In each
case I've read, the tuner in question has been a "T" configuration
(the commonest). One of the gotchas of a "T" tuner is that it can
appear to "match" an extremely nasty load (e.g. a short circuit) down
to a low SWR, while what's actually happening is that you're
"matching" the tuner's own internal losses. You can end up with
nearly 100% of your transmitter output being dissipated in the coil...
and this tends to let the magic smoke out, after a couple of minutes.

The same problem exists with other "T" tuners - it's not specific to
MFJ - so understanding the limits and vulnerabilities of that type of
tuner is important to proper use.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!