Discussion:
[Elecraft] counter probe
james h edwards
2002-10-07 23:50:01 UTC
Permalink
I also have lost my probe as i built the k2100 kit would a disk 10pf cap do
or should i order it from elecraft still very happy with my k2,n5tog 73`s
harold
Tom Hammond NØSS
2002-10-08 00:08:00 UTC
Permalink
Post by james h edwards
I also have lost my probe as i built the k2100 kit would a disk 10pf cap do
or should i order it from elecraft still very happy with my k2,n5tog 73`s
harold
ANY 10pF (or close) cap should work. That particular cap was chosen (I
believe) because it allowed a more streamlined design, rather than looking
like a pregnant guppy.

73,

Tom N0SS
Don Brown
2002-10-08 14:05:01 UTC
Permalink
Hi

A disk cap would not fit into the probe very well even though it would wo=
rk. You can order a replacement probe kit from Elecraft. It includes the =
connector parts, cable, tip and cap. Lost probes may be more common now t=
hat Elecraft does not recommend leaving it connected when the KPA100 is i=
nstalled. I think I will use one of those small zip lock bags to store mi=
ne and tape the bag to the side panel or the shield on the KPA100 inside =
the K2 so I won't loose it ;-)

Don Brown
KD5NDB
----- Original Message -----
From: james h edwards
Sent: Tuesday, October 08, 2002 2:41 AM
To: ***@mailman.qth.net
Subject: [Elecraft] counter probe

I also have lost my probe as i built the k2100 kit would a disk 10pf cap =
do
or should i order it from elecraft still very happy with my k2,n5tog 7=
3`s
harold

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Tom Hammond NØSS
2002-10-08 14:52:06 UTC
Permalink
... Lost probes may be more common now that Elecraft does not recommend
leaving it connected when the KPA100 is installed. I think I will use one
of those small zip lock bags to store mine and tape the bag to the side
panel or the shield on the KPA100 inside the K2 so I won't loose it ;-)
Someone, I believe it was Gary Surrency, gave me an idea which he uses, and
which has worked nicely for me for holding my FCTR probe when it is not in
use...

The 2D connectors used to secure the top/bottom/side panels of the K2 have
threaded holes which are not (completely) filled by screw length. I merely
stick the tip of the probe into the hole in the 2D connector and it's held
pretty securely there. So far, I've not had ANY problems with the tip
joggling loose, and my K2 gets quite a bit of beating around.

I use the 2D connector on the BACK panel and the half-filled hole which is
parallel to the back panel... this, plus just a bit of tension exerted by
the coax itself holds the FCTR tip nicely.

I must admit though... t'would be great if Elecraft would place an UNUSED
(grounded) thru-hole somewhere on the RF Board to hold one of the probe tip
sockets, so we could merely plug our FCTR probes in there when it's not in use.

73,

Tom N0SS
k***@ENTERZONE.NET
2002-10-08 15:30:03 UTC
Permalink
Someone, I believe it was Gary Surrency, gave me an idea which he uses, a=
nd=20
which has worked nicely for me for holding my FCTR probe when it is not i=
n=20
use...
=20
The 2D connectors used to secure the top/bottom/side panels of the K2 hav=
e=20
threaded holes which are not (completely) filled by screw length. I merel=
y=20
stick the tip of the probe into the hole in the 2D connector and it's hel=
d=20
pretty securely there. So far, I've not had ANY problems with the tip=20
joggling loose, and my K2 gets quite a bit of beating around.
=20
I use the 2D connector on the BACK panel and the half-filled hole which i=
s=20
parallel to the back panel... this, plus just a bit of tension exerted by=
=20
the coax itself holds the FCTR tip nicely.
=20
I must admit though... t'would be great if Elecraft would place an UNUSED=
=20
(grounded) thru-hole somewhere on the RF Board to hold one of the probe t=
ip=20
sockets, so we could merely plug our FCTR probes in there when it's not i=
n use.
=20
73,
=20
Tom N0SS
It gets kinda tight inside the K2 once the KPA100 is installed
however. I stopped leaving the probe inside the K2 once I built the
KPA100. Elecraft did provide us a handy storage location for the probes,
the QRP cover, manuals, etc. It's called the box. You know - That thing
that they shipped the K2 and/or the KPA100 in. Strangely enough,
everything fits in there! (How'd they do that?) ;-)

73 de John - KC4KGU
K2/100 #2490
George, W5YR
2002-10-08 18:15:00 UTC
Permalink
I am missing a serious point, as a new K2 owner. What is wrong with leaving
the probe in TP 2 all the time? That way CAL FIL is always available for
inspection of passbands, retuning, or whatever, without removing the top
cover.

73/72, George
Amateur Radio W5YR - the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489 Icom IC-765 #2349 Icom IC-756 PRO #2121
Post by k***@ENTERZONE.NET
Post by Tom Hammond NØSS
Someone, I believe it was Gary Surrency, gave me an idea which he uses, and
which has worked nicely for me for holding my FCTR probe when it is not in
use...
The 2D connectors used to secure the top/bottom/side panels of the K2 have
threaded holes which are not (completely) filled by screw length. I merely
stick the tip of the probe into the hole in the 2D connector and it's held
pretty securely there. So far, I've not had ANY problems with the tip
joggling loose, and my K2 gets quite a bit of beating around.
I use the 2D connector on the BACK panel and the half-filled hole which is
parallel to the back panel... this, plus just a bit of tension exerted by
the coax itself holds the FCTR tip nicely.
I must admit though... t'would be great if Elecraft would place an UNUSED
(grounded) thru-hole somewhere on the RF Board to hold one of the probe tip
sockets, so we could merely plug our FCTR probes in there when it's not in use.
73,
Tom N0SS
It gets kinda tight inside the K2 once the KPA100 is installed
however. I stopped leaving the probe inside the K2 once I built the
KPA100. Elecraft did provide us a handy storage location for the probes,
the QRP cover, manuals, etc. It's called the box. You know - That thing
that they shipped the K2 and/or the KPA100 in. Strangely enough,
everything fits in there! (How'd they do that?) ;-)
73 de John - KC4KGU
K2/100 #2490
Tom Hammond NØSS
2002-10-08 18:55:04 UTC
Permalink
Post by k***@ENTERZONE.NET
Well, with the KPA100, I don't think there's room in the rig to leave
it. It would be tighter than I would want to venture at least. Other
than that, I'm not sure. When #2490 was still QRP, I used to do exactly
what you suggest.
Oh, there's ample room to store it. The important thing is to keep the tip
from 'floating' around aimlessly inside the case. That's why I (kinda)
capture it in the 2D connector.

73,

Tom N0SS
Tom Hammond NØSS
2002-10-08 18:55:00 UTC
Permalink
This post might be inappropriate. Click to display it.
George, W5YR
2002-10-08 19:48:01 UTC
Permalink
Thanks, Tom - I will do a very careful examination of the K2 output signal
with this in mind.

TP2 in on the BFO signal line to the transmit mixer U10. So, I can
appreciate that any lack of integrity in the shielding of the FCTR probe
cable could allow other signals from the RF Board to be picked up and
introduced into the mixer input.

I find nothing in the manual about what to do with the probe after
completing CAL FIL, but perhaps something has been posted on the list.

73/72, George
Amateur Radio W5YR - the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489 Icom IC-765 #2349 Icom IC-756 PRO #2121
Post by Tom Hammond NØSS
Post by George, W5YR
I am missing a serious point, as a new K2 owner. What is wrong with leaving
the probe in TP 2 all the time? That way CAL FIL is always available for
inspection of passbands, retuning, or whatever, without removing the top
cover.
Someone will probably respond in a much more illustrative manner, but it is
my understanding that leaving the FCTR probe connected to TP2 can result in
some spurious signals (possibly) being transmitted... albeit at probably a
very low level.
For easily two years, I retained my FCTR probe in TP2... never noticed any
problems. However, IF there is even a remote possibility of such spurs, and
especially if the KPA100 is installed, I don't want to change having the PA
(or the KPA) amplifying them and having them go out to the antenna.
Just best to not risk it, even if it is a remote possibility.
However, I am ADAMANT about retaining the FCTR probe INSIDE my K2... WAY
too easy to either misplace or to just not have it available if I'd happen
to need it while on a trip where I couldn't find/make one quickly. Two
years in a row, when I was offering free Spectrogram XFIL alignments at
Dayton, I had numerous K2 owners bring in their K2s without the FCTR cable
and I'd have to cannibalize my K2 in order to complete their alignments...
a couple times I almost left mine in their K2!
73,
Tom N0SS
Vic Rosenthal
2002-10-08 21:36:00 UTC
Permalink
Post by George, W5YR
Thanks, Tom - I will do a very careful examination of the K2 output signal
with this in mind.
Do this test with the probe in and out: transmit on 20 meter CW and listen on
14.985 MHz (or thereabouts). You will notice a spur which is louder when the
probe is in. I think it's the third harmonic of the BFO.

Now, whether this can actually get radiated is a question that I can't answer.

Vic K2VCO
k***@ENTERZONE.NET
2002-10-08 18:21:01 UTC
Permalink
Well, with the KPA100, I don't think there's room in the rig to leave
it. It would be tighter than I would want to venture at least. Other
than that, I'm not sure. When #2490 was still QRP, I used to do exactly
what you suggest.

73 de John - KC4KGU
K2/100 #2490
I am missing a serious point, as a new K2 owner. What is wrong with leavi=
ng
the probe in TP 2 all the time? That way CAL FIL is always available for
inspection of passbands, retuning, or whatever, without removing the top
cover.
=20
73/72, George =20
Amateur Radio W5YR - the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489 Icom IC-765 #2349 Icom IC-756 PRO #2121
=20
=20
Post by k***@ENTERZONE.NET
=20
=20
Someone, I believe it was Gary Surrency, gave me an idea which he use=
s, and
Post by k***@ENTERZONE.NET
which has worked nicely for me for holding my FCTR probe when it is n=
ot in
Post by k***@ENTERZONE.NET
use...
The 2D connectors used to secure the top/bottom/side panels of the K2=
have
Post by k***@ENTERZONE.NET
threaded holes which are not (completely) filled by screw length. I m=
erely
Post by k***@ENTERZONE.NET
stick the tip of the probe into the hole in the 2D connector and it's=
held
Post by k***@ENTERZONE.NET
pretty securely there. So far, I've not had ANY problems with the tip
joggling loose, and my K2 gets quite a bit of beating around.
I use the 2D connector on the BACK panel and the half-filled hole whi=
ch is
Post by k***@ENTERZONE.NET
parallel to the back panel... this, plus just a bit of tension exerte=
d by
Post by k***@ENTERZONE.NET
the coax itself holds the FCTR tip nicely.
I must admit though... t'would be great if Elecraft would place an UN=
USED
Post by k***@ENTERZONE.NET
(grounded) thru-hole somewhere on the RF Board to hold one of the pro=
be tip
Post by k***@ENTERZONE.NET
sockets, so we could merely plug our FCTR probes in there when it's n=
ot in use.
Post by k***@ENTERZONE.NET
73,
Tom N0SS
=20
It gets kinda tight inside the K2 once the KPA100 is installed
however. I stopped leaving the probe inside the K2 once I built the
KPA100. Elecraft did provide us a handy storage location for the probe=
s,
Post by k***@ENTERZONE.NET
the QRP cover, manuals, etc. It's called the box. You know - That thi=
ng
Post by k***@ENTERZONE.NET
that they shipped the K2 and/or the KPA100 in. Strangely enough,
everything fits in there! (How'd they do that?) ;-)
=20
73 de John - KC4KGU
K2/100 #2490
=20
Stuart Rohre
2002-10-08 19:34:01 UTC
Permalink
One can install a fuse clip or similar under a screw for the speaker and
thus provide an anchor point for the RF probe.
73,
Stuart K5KVH
k***@ENTERZONE.NET
2002-10-08 19:23:01 UTC
Permalink
=20
Post by k***@ENTERZONE.NET
Well, with the KPA100, I don't think there's room in the rig to leave
it. It would be tighter than I would want to venture at least. Other
than that, I'm not sure. When #2490 was still QRP, I used to do exactly
what you suggest.
=20
Oh, there's ample room to store it. The important thing is to keep the ti=
p=20
from 'floating' around aimlessly inside the case. That's why I (kinda)=20
capture it in the 2D connector.
=20
73,
=20
Tom N0SS
Ahhh... The operative word here is "store". I'll have to open up the rig
and find some places to hide both probes. I think a couple of "buffer
tubes" from the fiber optic work should work nicely to capture both probe
tips and insulate them from anything as well.


73 de John - KC4KGU
K2/100 #2490
Ron D'Eau Claire
2002-10-08 22:03:00 UTC
Permalink
I had no trouble leaving it in. I did bend the cable over a bit just
above the "plug" on the r-f board so the cable didn't stick up so high.
That avoided the KPA100 'squashing' the cable down and stressing the
plug and jack on the r-f board. Other than that, it fits just fine!

Ron AC7AC
K2 # 1289


Well, with the KPA100, I don't think there's room in the rig to leave
it. It would be tighter than I would want to venture at least. Other
than that, I'm not sure. When #2490 was still QRP, I used to do exactly
what you suggest.

73 de John - KC4KGU
K2/100 #2490
Ron D'Eau Claire
2002-10-08 22:15:01 UTC
Permalink
If that's the case, George, please post your results on the reflector.
It's one thing for the Elecraft guys to be concerned with the FCC rules
to keep themselves from being shut down, but if the probe causes
significant spurs in the output, it's simply not good practice to leave
it in place at ANY power level.

Most of the ops on this reflector know full well just how far a little
r-f can go.

It's one thing when a simple rig has some inherent spurs - like the
little one-stage QRPp rigs. I don't have an issue with one of those or a
"boat anchor" that doesn't meet all the current spex. But it's something
else entirely to radiate a spur simply because a test probe that is not
needed is left plugged in.

Ron (where did I put that screwdriver for the cover screws?) AC7AC
K2 # 1289


Thanks, Tom - I will do a very careful examination of the K2 output
signal with this in mind.

TP2 in on the BFO signal line to the transmit mixer U10. So, I can
appreciate that any lack of integrity in the shielding of the FCTR probe
cable could allow other signals from the RF Board to be picked up and
introduced into the mixer input.

I find nothing in the manual about what to do with the probe after
completing CAL FIL, but perhaps something has been posted on the list.

73/72, George
Amateur Radio W5YR - the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489 Icom IC-765 #2349 Icom IC-756 PRO #2121
George, W5YR
2002-10-08 22:30:10 UTC
Permalink
I was just chatting with Eric, WA6HHQ, on 18,132 and one of the topics that
came up was how to deal with the FCTR cable. He strongly recommends
*against* leaving the cable or anything plugged into TP2. Considering the
location of the TP in the circuit, I can see where such a low-level signal
point should NOT have an antenna connected to it! <:}

So, based upon Eric's comments I will remove the cable from TP2 and avoid
any possible problems.

I will soon be posting a detailed description of some mods that I have
engineered for the K2. Eric blessed the effort and suggested that I pass
along the details.

73/72, George
Amateur Radio W5YR - the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489 Icom IC-765 #2349 Icom IC-756 PRO #2121
Post by Ron D'Eau Claire
If that's the case, George, please post your results on the reflector.
It's one thing for the Elecraft guys to be concerned with the FCC rules
to keep themselves from being shut down, but if the probe causes
significant spurs in the output, it's simply not good practice to leave
it in place at ANY power level.
Most of the ops on this reflector know full well just how far a little
r-f can go.
It's one thing when a simple rig has some inherent spurs - like the
little one-stage QRPp rigs. I don't have an issue with one of those or a
"boat anchor" that doesn't meet all the current spex. But it's something
else entirely to radiate a spur simply because a test probe that is not
needed is left plugged in.
Ron (where did I put that screwdriver for the cover screws?) AC7AC
K2 # 1289
Richard Kronick
2002-10-08 22:27:59 UTC
Permalink
Elecraft K2 Revison 2 Firmware instruction dated 28 August 2001 says on
Page 4, step 7 under VFO Calibration:
"7. Move the K2 counter cable to BFO test point, TP2(or remove the cable
and store it).
8. Re-install the top cover."
Maybe the experts will be able to give us the company position.
73 Dick W4RAK



----- Original Message -----
From: Ron D'Eau Claire <***@easystreet.com>
Date: Tuesday, October 8, 2002 5:05 pm
Subject: RE: [Elecraft] counter probe
Post by Ron D'Eau Claire
If that's the case, George, please post your results on the reflector.
It's one thing for the Elecraft guys to be concerned with the FCC
rulesto keep themselves from being shut down, but if the probe causes
significant spurs in the output, it's simply not good practice to
leaveit in place at ANY power level.
Most of the ops on this reflector know full well just how far a little
r-f can go.
It's one thing when a simple rig has some inherent spurs - like the
little one-stage QRPp rigs. I don't have an issue with one of
those or a
"boat anchor" that doesn't meet all the current spex. But it's
somethingelse entirely to radiate a spur simply because a test
probe that is not
needed is left plugged in.
Ron (where did I put that screwdriver for the cover screws?) AC7AC
K2 # 1289
Thanks, Tom - I will do a very careful examination of the K2 output
signal with this in mind.
TP2 in on the BFO signal line to the transmit mixer U10. So, I can
appreciate that any lack of integrity in the shielding of the FCTR
probecable could allow other signals from the RF Board to be
picked up and
introduced into the mixer input.
I find nothing in the manual about what to do with the probe after
completing CAL FIL, but perhaps something has been posted on the list.
73/72, George
Amateur Radio W5YR - the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489 Icom IC-765 #2349 Icom IC-756 PRO #2121
_______________________________________________
You must be a list member to post to the list.
Postings must be plain text (no HTML or attachments).
See: http://mailman.qth.net/mailman/listinfo/elecraft
Elecraft Web Page: http://www.elecraft.com
k***@earthlink.net
2002-10-08 22:56:02 UTC
Permalink
I can't remember what page it is on but the K2/100 manual tells one to remove the probe because of spurs. So it is in the manual just not in the K2 manual.
Kevin. KD5ONS
Post by George, W5YR
I was just chatting with Eric, WA6HHQ, on 18,132 and one of the topics that
came up was how to deal with the FCTR cable. He strongly recommends
*against* leaving the cable or anything plugged into TP2. Considering the
location of the TP in the circuit, I can see where such a low-level signal
point should NOT have an antenna connected to it! <:}
So, based upon Eric's comments I will remove the cable from TP2 and avoid
any possible problems.
I will soon be posting a detailed description of some mods that I have
engineered for the K2. Eric blessed the effort and suggested that I pass
along the details.
73/72, George
Amateur Radio W5YR - the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489 Icom IC-765 #2349 Icom IC-756 PRO #2121
Post by Ron D'Eau Claire
If that's the case, George, please post your results on the reflector.
It's one thing for the Elecraft guys to be concerned with the FCC rules
to keep themselves from being shut down, but if the probe causes
significant spurs in the output, it's simply not good practice to leave
it in place at ANY power level.
Most of the ops on this reflector know full well just how far a little
r-f can go.
It's one thing when a simple rig has some inherent spurs - like the
little one-stage QRPp rigs. I don't have an issue with one of those or a
"boat anchor" that doesn't meet all the current spex. But it's something
else entirely to radiate a spur simply because a test probe that is not
needed is left plugged in.
Ron (where did I put that screwdriver for the cover screws?) AC7AC
K2 # 1289
_______________________________________________
You must be a list member to post to the list.
Postings must be plain text (no HTML or attachments).
See: http://mailman.qth.net/mailman/listinfo/elecraft
Elecraft Web Page: http://www.elecraft.com
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