Greetings all!
To those considering a new kit, I offer my opinion of one I just assembled,
an Emtech NW-40.
It's been a while since I assembled a xcvr kit, so I gave the whole
selection business a lot of consideration. There's a lot of really good
kits out there, all with similar performance and somewhat similar designs,
so the decision is tough.
One thing I insisted on was decent frequency coverage, more than can be
realized with varactor tuning. The NW series kits have "real" tuning caps
and my 40M version goes from 7.000 to about 7.220. That gives me coverage
through the novice portion of the band and beyond, something I consider a
bonus for the times that I'm dit-dit'ed out and just want to read the mail
on a fone QSO, or even a broadcast station. And that's testimony to one of
its most impressive features - stability, near-synthesizer stability.
Folks, this thing doesn't move! At least, it doesn't in a normal
evironment, anyway. I can put it on a fone QSO and never have to touch it
up. I'm pretty amazed. And it'll hold its own with a BC station, too. You
know, 15 years ago it was generally considered taboo to design a VFO with a
toroid, because of drift. But with the core mixes that are now available, a
good designer can do it. Roy did it. Also, the radio has a variable
bandwidth xtal filter, RIT, smooth QSK, and LOTS OF AUDIO. And the receiver
is hot. It sits right beside an ICOM-765 and an ICOM R9000, and it can hear
anything they can. The transmitter set up and tuned easily, and wide open
mine did about 9.5 watts, almost QRO!
Functional diagram:
Rx NE602 --> MC1350 --> NE602 --> LM386
Tx NE602 --> 2N2222 --> 2N2219 --> 2SC1678
How about construction? Easy. The best instructions I've seen since
Heathkit. The kit has one PCB, onto which you install components and test
one section at a time. Each section's components are packaged and labeled
separately to make sorting a no-brainer. For example, you install the
components for the VFO and a method is provided for you to verify its
operation, and so on until completion. You don't have to stuff a board full
of a hundred or so parts at one time, only then to find that things don't
work. There are also plenty of illustrations, including both sides of the
PCB, component diagrams and descriptions, wiring diagrams, schematic
diagram, parts list, comprehensive voltage chart, and good coil winding
instructions (four toroids - piece of cake.)
The PCB is a work of art. I have had a soldering iron on literally
thousands of circuit boards, and this one is as quality as any consumer
grade board I've seen. Single-sided, silkscreened, fully tinned and masked.
Over the holidays, in taking advantage of a special priced package, I got
the optional audio filter, and cabinet. The cabinet is drilled, punched,
and silkscreened. Looks good. But, a template is also provided in the kit
instructions for mounting the xcvr board in a Radio Shack enclosure, in case
you want to "roll your own." The audio filter is a standard design two-pole
version, but uses precision resistors. Components are provided so that
during construction you can choose between two different center frequencies
and two levels of gain. It works very well, and should probably be an
automatic purchase. Its presence also helps make T-R alignment a very brief
task.
What didn't I like? I honestly have to look hard. I would like to see the
main PCB accommodate the optional audio filter components rather than on a
second PCB, even though it is very small. And I would probably like to have
some kind of RF gain control, although it is not often needed. Obviously, I
could add one, myself.
So, there you have it. I could probably go on for several more paragraphs
but this thing is too long, now. As you can probably tell, I am very
positive about this kit. It is well designed and very well prepared, not
just a bunch of parts thrown in a box. And it went together and performed
exactly as the instructions said. I think I got far more than my money's worth.
OK, Roy, I want a multiband version of this thing!
Full disclaimer - absolutely no connection or association with Emtech, other
than a being a very satisfied customer.
72,73
Rick - KI4PZ
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