K2 - Need Some Help!

[stan levandowski]

There's a 4.7 pf cap that goes into "C6" on the upper right edge of the
bottom of the RF Board.  The instructions are subject to a great deal of
interpretation and have me absolutely baffled.  Perhaps I think too
deeply, or, maybe I just think "differently", or, my brainpower is in
QRPp mode today.

I'm now looking at the BOTTOM of the RF Board, with C104 to my immediate
left.  I'm going to label the three holes at "C6"  as  "1", "2", and "3"
with "1" closest to C104.

Now, I think the "two outer" holes in which the 4.7 pf cap goes should
be "2" and "3".

Did I get it right?  I'd appreciate hearing from someone who has already
gotten past this.  It's page 59 of the manual.


This was like a brainteaser!  The two outer holes could also be
construed as #1 and #3, in which case the instructions could have simply
said to avoid using the middle hole.  The directions to "Use the outer
of the three holes, not the two holes closest to the left edge of the
board" are confusing because the "left" edge of the board depends upon
whether one is holding it top up or bottom up and the previous sentence
in the manual had the builder looking at J15 on the top of the board.

Thanks much!


Stan Levandowski WB2LQF
HF QRP CW -- Doing more with less for over 50 years!
QCWA #35038   OOTC #4558   NAQCC #4740   SKCC #6488   FISTS #(Pending)
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[Andrew Moore-3]

I remember having the very same brain failure at that point in the
construction.  It can be very confusing.

If you check the schematics in Appendix B of the K2 manual, on the RF board
page showing the antenna connector, you can see the 4.7 pF cap connected at
pins 1 and 3, which lets the signal bypass the 60 m module (assuming it's
not installed) -- not across adjacent pins such as 1,2 or 2,3.

This really should be clearer in the manual.

After building my K2 and connecting the cap across the wrong pins, the
receiver seemed deaf, and I ended up doing signal tracing until I found out
there was no path between the antenna and the rest of the receiver.  It took
help from the Elecraft list to realize this.  Guess it's my turn!

--Andrew, NV1B
..


On Sat, Sep 18, 2010 at 1:22 PM, stan levandowski <[hidden email]>wrote:

> There's a 4.7 pf cap that goes into "C6" on the upper right edge of the
> bottom of the RF Board.  The instructions are subject to a great deal of
> interpretation and have me absolutely baffled.  Perhaps I think too
> deeply, or, maybe I just think "differently", or, my brainpower is in
> QRPp mode today.
>
>
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[Don Wilhelm-4]

  Stan,

Are you using the new manual (Rev G) or an older one?

There are 3 holes - C6 goes into the outermost holes of the set of 3
("the outer two holes of this set of 3 pads").  In other words, the
leads go into holes 1 and 3.

If you can explain how your thought process is causing you to think
otherwise, perhaps the manual can be changed again.
Can you explain what you are attributing "outer" to?  Outer edge of the
board?  Outer 2 holes? Outer left side of the board? Outer right side of
the board?  It has long surprised me how this has been misinterpreted,
but then not everyone interprets the same way.

Previously it did not use the "outer two of the set of 3" phrase, but
simply said the "two outer holes", and it was changed to (hopefully) be
more descriptive - apparently that effort failed.  If you can be helpful
with describing the proper two holes using a better phrase, please
suggest it.  Maybe your addition of a parenthetical expression "(leave
the center hole empty) would be helpful - please let us know.

73,
Don W3FPR

On 9/18/2010 1:22 PM, stan levandowski wrote:

> There's a 4.7 pf cap that goes into "C6" on the upper right edge of the
> bottom of the RF Board.  The instructions are subject to a great deal of
> interpretation and have me absolutely baffled.  Perhaps I think too
> deeply, or, maybe I just think "differently", or, my brainpower is in
> QRPp mode today.
>
> I'm now looking at the BOTTOM of the RF Board, with C104 to my immediate
> left.  I'm going to label the three holes at "C6"  as  "1", "2", and "3"
> with "1" closest to C104.
>
> Now, I think the "two outer" holes in which the 4.7 pf cap goes should
> be "2" and "3".
>
> Did I get it right?  I'd appreciate hearing from someone who has already
> gotten past this.  It's page 59 of the manual.
>
>
> This was like a brainteaser!  The two outer holes could also be
> construed as #1 and #3, in which case the instructions could have simply
> said to avoid using the middle hole.  The directions to "Use the outer
> of the three holes, not the two holes closest to the left edge of the
> board" are confusing because the "left" edge of the board depends upon
> whether one is holding it top up or bottom up and the previous sentence
> in the manual had the builder looking at J15 on the top of the board.
>

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[Andrew Moore-3]

w3fpr> If you can explain how your thought process is causing you to think
otherwise, perhaps the manual can be changed again.

Apparently Stan and I were similarly confused.  In the Rev. G manual,
"Install C6 (4.7 pF) into the outer two holes of this set of 3 pads (of
J15)" could be interpreted as the two adjacent pins closest to the left edge
of the board, if you're looking at it from the normal operating position.
In this case, "outer" is relative to, say, the center of the board.  It
could also be interpreted as relative to the middle pin of the 3-pin group.

The problem is "outer" is a relative term, and the reference isn't clearly
defined.

The clause "of the 3 pads (of J15)" clearly tells you what pin grouping
we're dealing with, but still lacks the critical reference for "outer."

Possible alternatives:

"Install C6 (4.7 pF) into pins 1 and 3 of the 3-pin pad J15" (assuming
silkscreen, pin numbers, etc. won't change in the future)

"Install C6 (4.7 pF) into the outer two holes (relative to the middle pin of
the group) of the 3-pad group J15"

I'm not sure it's worth redoing the printed manual -- as there's now some
good documentation on the reflector -- but maybe just keep the existing
manual (or fixing the online copy only), and do it with an errata sheet for
existing print copies.

--Andrew, NV1B
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