TL;DR: if you are unsure about whether you should give a go to building
a QMX+ kit, then just go ahead and get one to build. It is easy, and it
is a lot of fun.
Longer version below.
Yes, you must believe the title: the QMX+ is really the easiest of all
the QRP-Labs transceiver kits. The build is probably second in
difficulty only to the 20W dummy load kit, but that does not count a
transceiver proper, right? HI.
I have built 2 QCX mini, 3 QMX, this QMX+ (no digi stuff here, so no QDX
in my shack, sorry :P), two semi-home-brew versions of the usdx in the
design by Barb WB2CBA, which are kinda in the same family of the QCX, on
top of several other kits from a variety of other suppliers. All these
kits have been a joy to build, including my first QMX Rev.1, serial #
around 100, one of those which had the short in the 5V SMPS, which
required some throrough testing and a little surgery HI. The QMX can
indeed be slightly tricky to build as the PCB is quite packed.
But boy, the QMX+ is on a totally different level of easyness. No
special space constraints. No tight mechanical fits (the postponed
soldering of the two right pins of the tune encoder is really a minor
one, and was solved brilliantly by Hans). No fear of ripping off some
other SMD components while soldering. Well, I have used my 2.5mm scalpel
tip to solder all the QMX kits, without issues, but for the QMX+ you can
easily get on with a 5mm one, no joking.
The only thing that requires some care, really, is the placement of
connectors at the back of the PCB, as the holes in the real panel are
snug and you really need to get the connectors as straigt as possible.
And that's totally straightforward to do, by soldering only one of the
pins of each connector and then making sure that the connector sits
straight before soldering the other ones. But for the rest, there is
really no sticky point at all, and it is much easier to get around it
than in the QMX, where the space is really tight.
The amount of soldering required is not massive by any standard, and
relatively little compared to the QCX mini and the QMX. The stuff to
solder is well spaced-apart. The pervasive use of 0.33mm enameled wire
eliminated almost entirely the potential issues with remaining enamel
and/or imperfect joints. There are literally too few things that can go
wrong during such a build. The worst that can happen is that your cat
jumps on the lab desk splattering all the caps you have just sorted up
all over the place. Don't ask me how I know, OK? HI
I mean, if you can read the assembly manual, and you know which side of
the soldering iron to grab, and you are the average human being who
considers winding toroids as one of the most gratifying and relaxing
past-times on Earth (me! me!), then the QMX+ build is literally a piece
of cake. Almost too easy, and definitely uneventful. It's just amazing
for such a powerful rig.
I completed the build in a few hours, perhaps 5 in total over two days,
without rushing through it. About one third of the time was spent
winding toroids (me! me!). And when I was done with my final checks and
dared applying power, all I got was a fantastic rig, ready to operate
immediately on 12 bands. I spent about 20 minutes in the serial console
after the first boot, checking all the sweeps. They were all almost
exactly as expected. I tinkered with the 20-17-15 LPF for about 10
minutes, trying to squeeze some more power on 20m, but then I realised
that it made totally no sense and stopped straight away. In hindsight, I
should have used that time to make a QSO :)
I have been using the rig for a few days, and it is just great. But
that's another story. This was just to say that building a QMX+ from a
kit is dead easy, and fun.
72/73 de Enzo M0KTZ
DISCLAIMER: This post reflects my own personal opinions, which cannot be
ascribed to anyone else, including in particular any club or association
to which I belong or to which I am connected. I have no vested interest
in any of the QRP-Labs business. I have no business or personal relation
whatsoever with Hans Summers or with QRP-Labs. All the kits I have built
have been paid by me and by noone else, but please don't tell my XYL how
many are they: that's our little secret! I have met Hans once, we had a
very interesting chat and we have exchanged emails on several subjects,
but never on the easyness of building a QMX+ :P My opinion is obviously
biased by the fact that I have a sincere appreciation for the QRP-Labs
stuff that I have built and used so far. I trust you can live with that
;)
--
Daniel Conklin
KB9NBL
Bruce Akhurst
Bill, N4QA/QRP