Hi Charlie:
At 06:45 PM 4/6/05, W0YG, Charlie Summers wrote:
Being a newbie and just getting SN 4853 going, I don't know what this
tuning indicator you have referred to is. I would like to know a bit more
about it. Is there some place I can read up on this modification.
SN 4853 is on the air! I am now building up the KPA100 module. When
completed, I am going back through the alignment/tuning procedure once
more then wrapping this project up. It has been a hoot!
Congratulations on having completed s/n 4853!!! You'll love the rig.
And, tanks for asking about the SMD LED CW (Zero Beat) Tuning Indicator...
sometimes I tend to forget that no everyone was around when this subject
first came up, or when it reappeared most recently...
About 5-6 years ago, Jerry Henshaw, KR5L, designed a PLL circuit which took
a little signal from the K2's AF output and drove a PLL which would blink a
LED when the radio was tuned closely (generally +/- 50Hz, if I recall) to a
signal which matched the K2's sidetone... thus indicating that the K2 was
close to being zero beat with the received signal. It was meant as a tuning
aid for some operators who had difficulty achieving a good zero beat by ear
(by matching the K2's sidetone against that of the receive signal.
I designed a small PC board for Jerry, using thru-hole components, and I
believe he sold a dozen or so (maybe) of the boards over the next year.
After that time, the circuit kinda lost interest and little was said about
it for another year or two.
Then, I somehow found (or was directed to, I forget) a similar circuit
which was offered by Bob Wolbert, K6XX, on his web site, but which seemed a
bit nicer than the original design. I made up a few (thru-hole) boards, and
offered them to builders. Sold a few. but the PC board was still a bit
larger than might have been desired.
So, for the first time in my short life, I decided to try designing the
same circuit using surface-mount devices (SMDs), in an effort to get the
board size down a bit (slightly larger than a large postage stamp), AND to
add a small degree of challenge to the building of the kit.
With the help of several Elecraft builders, we devised installation
instructions for the kit into all of the Elecraft transceivers (K2, K1, and
KX1), and the K1 installation docs also can be used as a general set of
installation instructions for just about any other radio as well.
THIS time, when I offered the PC board for sale, a number of folks groused
about having to first find and then order the components... so I caved in
and started kitting the project at a complete kit.
I was amazed that the project took off... I sent out over 360 kits in the
space of 3-4 months...!!! And to date, I know of no complete failures...
though they may not have been reported to me... <G> A couple builders had
problems with solder shorts between components, and one PC board (which I
supplied) which had a broken land, and another one which had two shorted
lands, but otherwise I know of no problems... so far.
Once I got the 360+ kits made up and sent out, I'd had about as much 'fun'
as I could muster (and a LOT HIGHER REGARD FOR THE FOLKS WHO MAKE AND SELL
KITS FOR A LIVING!), and I now only offer the bare PC boards for sale. The
documentation which appears on my web site www.n0ss.net included a
complete parts list and the Mouser part numbers so builders can order the
components from one location with as little pain and suffering as possible.
The docs also offer complete assembly and alignment instructions.
Though assembly does require a steady hand, and either good eyes or a
decent magnifier, assembly of the kit is not difficult, and alignment is
fast easy as well. And only four (4) wires are required to attach the kit
to your radio. KX1 owners will require two (2) user-supplied 1/4W resistors
to go with their installation, to drop the AF output lever before it gets
to the indicator. Oh, I almost forgot, K1 owners will have to supply an LED
of their choosing as well.
In the K2, the tuning indicator is usually installed such that it will
blink the 10th LED of the S-meter LED to indicate when you're tuned to the
other guy's signal. Don Wilhelm, W3FPR, tells me he prefers to use a
separate LED for this purpose, and he mounts a mini-LED inside the K2s
[LOCK] button. Of course you, the builder, can choose how you wish to
implement the LED indicator.
In the K1, the user-supplied LED can be mounted in a hole you'd have to
drill in the case, or you can use the suggested implementation which mounts
the LED AGAINST the existing RIT LED and illuminates the RIT LED by
radiated light. Seems to work nicely.
In the KX1, the existing MAP LIGHT is utilized as the indicator, allowing
for installation without having to drill holes or having to add a
user-supplied LED.
So, that's it. Hope this has given you enough info. If not, please feel
free to ask.
Complete docs are available at www.n0ss.net
Write me if you are interested in a PC board. They're $6 ($7 DX) postpaid
to your stateside mailbox.
73,
Tom Hammond N0SS
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