Michael,
Although an absolute null would indeed be zero, the 10 to 12 range is
about as low as you can get - the K2 display is reading in millivolts
and there is some noise picked up and coupled into the op amp input
which limits the low end of the reading capability. The same problem is
JT:
Your external wattmeter is BETWEEN the KAT2 and the antenna...!
The KAT2 is providing a match to the K2, NOT the external meter, which is
AHEAD of the KAT2 and in a place where no matching is being done.
Remember, the KAT2 does NOT TUNE the antenna/coax, it only provides a
conjugate match
On 10/5/07, Tree [EMAIL PROTECTED] wrote:
Perfectly expected. The KAT2 is inside the K2 - and is just matching your
bad SWR to the finals. The bad SWR is still there outside the radio.
Yeah, I thought of this just after I posted. Sometimes I don't get it
til I actually write out the problem.
JT,
Unless you have somehow placed the W1 between the K2 and the *input* to
the KAT2 (not an easy feat), you will not see any reduction of SWR on
the antenna transmission line.
The KAT2 (or any tuner for that matter) does not change the antenna, it
just adds inductance and capacity to
need to go
through it several times.
Hope this helps
Thanks
Don Brown
KD5NDB
- Original Message -
From: Don Wilhelm [EMAIL PROTECTED]
To: JT Croteau [EMAIL PROTECTED]
Cc: elecraft@mailman.qth.net
Sent: Friday, September 28, 2007 8:22 PM
Subject: Re: [Elecraft] KAT2: C55 Adjustment
Don and all,
This is exactly the method I have been using on all the Elecraft
wattmeters that I have worked on for several years now. I believe you
mentioned it first, so I do have to give you all the credit for this
great idea.
It does result in a more accurate setting of the trimmer
Thanks to all for the replies.
As of right now, I'm going to blame it on a bad relay. I had damaged
one, K8, slightly during install but thought it was only a flesh wound
and that it wouldn't effect operation until I could get it replaced.
Offender removed and I will order a replacement next
JT,
Use a fully insulated tuning tool - both ends of the trimmer cap are
floating above ground, so you will see a lot of 'hand capacitance'
effects with a metallic screwdriver. If you can achieve a null below 9
or 10, that is a normal low value.
Tune slowly and you can obtain the null. If
Don Wilhelm wrote:
R6 is not to be installed until some initial checks are made. The
manual will tell you when to add it.
I got caught out by this and had to unsolder one end later. The
manual needs to explicitly state that R6 is not installed with the
other resistors.
If you can't find
G'day,
| R6 is not to be installed until some initial checks are made. The
| manual will tell you when to add it.
|
| I got caught out by this and had to unsolder one end later. The
| manual needs to explicitly state that R6 is not installed with the
| other resistors.
I guess most of us
Andrew,
There must be a lockwasher at one end of the standoff - it is an overall
length thing, so it really does not matter which end of the standoff the
lockwasher is placed. Do what seems right - yes, the manual says it
both ways, and that is confusing. It is easier to put the lockwasher
Joey (I assume - you did not sign your name or call),
The green wire connects with Control Board P4 pin 2. And YES, it will
look like the manual diagram when correctly completed. The green wire
goes toward the top of P4.
Yes, in this case, the arrow is closest to J8 pin 2. The rest of the
Steve,
It is not likely that you will be able to achieve a 000 indication when
nulling the KAT2 - in fact I believe that fact is pointed out in the
manual. You should strive for the lowest reading possible, and if that
lowest reading is less than 010, all is likely OK. Do not simply stop
: Re: [Elecraft] KAT2 CALS Problem
I would bet that the other antenna input is selected on 15 meters
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Bob,
Try the menu parameter for the ATU - either CALP or CALS will bypass the LC
section of the ATU, see the KAT2 (or KAT100) manual.
73,
Don W3FPR
-Original Message-
I need to disable the antenna tuner in my K2, while conducting a test.
I can't seem to find a menu option to
Bosse,
That sounds like a soldering problem. Look carefully at the soldering at
K18 pins 1 and 10 and the soldering at U1 pin 26.
You could also have a problem with the socket of U1, or a pin bent under the
IC and not properly in the socket pin. Check for continuity between K18 pin
10 and the
Richard,
If your power output indication varies with frequency, then it could be that
the KAT2 wattmeter diodes are frequency sensitive.
BUT, I must ask - how do you know your dummy load is not frequency sensitive
as well, and what is the accuracy of your external wattmeter? Many
wattmeters
Richard,
Those numbers are in the ballpark - the exact voltage at U4 pin 1 will
depend on the power output as well as the position of trimmer R1 - if your
R1 is not quite to the center position, that would explain having less than
3 volts. The bridge null is sharp, and if you have a DMM that
Johnny,
Things are not always perfect, so you can expect some variation.
The 1N5711s in the KAT2 are not entirely frequency independent, and the
detector in the LP100 is similarly frequency dependent. The exact results
will vary with the particular 1N5711 diode that is in your KAT2 and the
RC,
Re-do the power and SWR calibration, and then try it into a 50 ohm dummy
load. Tell us what you find.
I know that is not an answer to your total problem, but there has to be a
starting point, so verify that calibration first and we can go from there.
In case you cannot achieve a good
There are also some pins quite visible but right next to plate-through
holes (vias) and if you don't look with a loupe you might think the coil
is soldered...not that I know from experience, hihi.
73,
Leigh/WA5ZNU
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Post to:
I rechecked the pins on the relays [ugh] found a donut solder joint
reflowed it and two others Did the power calibration...
Display in tune is now 5.6F 0.0r voltage on DMM is 9.90vdc
RCkc5wa
-
Don Wilhelm wrote:
RC,
Re-do the power and SWR calibration, and then
Chuck,
Did you ever hear the relays click once? Like the first time you attempted
a TUNE with that antenna.
The KAT2 remembers the tuning settings for each band (on each of ANT1 and
ANT2), and when that band is selected there are some clicks from the KAT2
when the bandchange is made along with
getting some spill-over/leakage
into the other Antenna channel.
Thanks, again.
-Original Message-
From: Don Wilhelm [mailto:[EMAIL PROTECTED]
Sent: Saturday, November 04, 2006 7:47 AM
To: Chuck; elecraft@mailman.qth.net
Subject: RE: [Elecraft] KAT2 Questionis mine working?
Chuck
I gave up on LDG after having the Elecraft tuners. I was very disappointed.
The only non elecraft tuner I am successfully using is a remote SGC for a
ladder line fed off-center lazy L with an elevated ground plane which while
it tunes, doesn't work squat. I am pulling that one down and going with
Alex,
Use your DVM to measure the voltage at the wiper of the reflected
potentiometer - adjust for a minimum. If the minimum is high, then check
your work - the diode orientation, the winding of the bifilar transformer,
and other components in the circuit (look at the schematic to identify the
Hi Bob:
It has been my experience with several KAT2s that the KAT2 will tune with
anything *Greater Than* 0.1 watts commanded on the Power control where it
shows Lo P. I think you have something else wrong there.
Good luck...
73, Ken K3IU
Ken,
Thanks for the advice. A number of other
Build yourself an attenuator (3 or 4db should be fine), and the K2 will be
happy and the amp will be happy and the KAT2 will match all (well half - the
attenuator to amp side needs to be close to 50 ohms. The K2 side should be
too).
Dan / WG4S / K2 #2456
snip
If I set the power on the K2 much
Hi Bob:
It has been my experience with several KAT2s that the KAT2 will tune with
anything *Greater Than* 0.1 watts commanded on the Power control where it
shows Lo P. I think you have something else wrong there.
Good luck...
73, Ken K3IU
-Original Message-
From: [EMAIL PROTECTED]
Bob,
Yes, the K2 power must be set to 2 watts or above to allow the ATU to tune.
The firmware will reduce the power for tuning if it is set higher, but it
will not increase the power to the best of my knowledge.
You may want to try an attenuator pad between the K2 and the amp if you do
not need
In a message dated 4/17/06 7:00:22 AM Eastern Daylight Time,
[EMAIL PROTECTED] writes:
Does the signal pass through the KAT2 in both TX and RX
Yes
73 de Jim, N2EY
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You must be a
Rolf Moberg wrote:
Antenna switch is working. The big question are the relays. I can hear
them clicking when scrolling through ATU menu as described in manual.
However, no relay clicks are heard when pressing TUNE in CALP mode. Why?
I admit an award to myself, Year 2005 Wooden Eye. Of course
I also had problems reading the K2 display when nulling C55. For me it
was much easier to find the null by using a DC voltmeter to measure
the reflected voltage signal into the PIC on the KAT2. My memory says
it was pin 4, but check the schematic to be sure.
Also, be very sure you have a good
Rolf,
Yes the null value is probably fine at 10, just get it as low as possible -
the null is quite sharp. If you have an analog voltmeter you can read the
reflected voltage and see the null as a dip more easily than waiting for a
digital meter to update the reading.
For power calibration with
Rolf,
You will have to somehow get J4 and J5 perpendicular to the board. Forcing
them into alignment with the screws will likely break something.
I have not had any past problems in accomplishing that feat. Be certain C60
and C45 are the proper values of 0.001 uf (marked 102) - the .001
Roger,
The bottom line is that you have to end up with one lockwasher between the
standoff and the board. It matters not which end of the standoff that
occurs on - the lockwasher adds a bit more length to the standoff and it is
sometimes needed to assure adequate clearance for the board above
Well, my KAT2 saga continues.
I did indeed find some unsoldered pins on one of the relays, and
corrected this.
Now, however, I seem to have the opposite problem. When trying to
perform the CALn procedure, instead of having too much reflected power,
I now have no power (forward or
The first thing that occurs to me is that the single turn of wire through
the center of T1 may be missing. The second thing is that T1 itself may not
be properly wound or properly soldered. Check that the proper color wire is
inserted into the proper holes (the color of the wire in hole 2 should
[mailto:[EMAIL PROTECTED]
Sent: Saturday, September 17, 2005 4:28 PM
To: Sanger, Joseph
Subject: Re: [Elecraft] KAT2 - Bridge Null Adjustment problem
Have you installed R6 yet? Page 17 - 5th step is to install a 47 ohm
1/4
watt resistor in the KAT2. This is the info to the K2 microprocessor to
set
Do any of the relays operate (click), or is the problem only with the ones
on the L-C board?
If none of them operate, check that the MCU is properly seated in its socket
with no pins either sticking out to the side of the socket or bent under
(you should remove the MCU to check for bent under
I've built the KAT2 and have become stuck at the Bull Bridge
Adjustment stage (P. 16 Rev. D Manual). No matter where I place the
trim capacitor C55, I get Hi on the screen when I do a Tune in CALn
mode.
Carl:
I usually make this adjustment using an old analog voltmeter on the lowest
dc
I agree with Vic, and do just that with the KAT100.
73,
Geoff
GM4ESD
-
Vic Rosenthal wrote:
tom.w3qs wrote:
Would it be wise, prudent, useful, great idea, stupid - you pick 'em - to
put the K2 Dummy Load on KAT Ant 2 and the regular antenna on
Craig,
The KAT2 has changed little. To bring it up to date, change R6 to 470 ohms
and upgrade the firmware. That is all that I am aware of - if someone has
better info, please correct me. Mine works fine with those 2 changes, and
my unit was one of the initial Field Test models.
73,
Don W3FPR
David,
Good choice - but next you will be needing an EC2 enclosure to mount the
KPA100 so you can have a 'pick up and go' station.
The changes you have already made for the KPA100 will work fine with the
KAT2. Actually, fewer changes need to be made on the base K2 to install the
KAT2 (I am
Andrew,
Yes, I believe the manual is inconsistant on that point. Just make certain
there is one lockwasher between the standoff and the PC board (not 2) - and
it doesn't matter which end of the standoff has the lockwasher next to the
PC board - do it whichever way is better for you. I prefer to
Fred,
Great that you had success with just the replacement of the voltage
regulator. FB on the perormance of the KAT2 - yes it will load just about
any hunk of wire - its only weakness is in attempting to load very high
imedances such as an end fed half wave antenna. Keep that flag flapping.
Fred,
Solve the voltage regulator situation first - it certainly sounds like it is
either bad or there is a bad connection somewhere in the voltage supply
path, in any case it is not regulating to 6 volts.
R6 is installed after the balance alignment and you are not there yet.
Furthermore, if you
Find installation of R6 as follows:
Page 17, last step before the paragraph: Power Calibration (R1 and R2)
Congrats and good luck.
73, Joe, aa4nn
I have just completed building my KAT2 for K2 SN4519. I have one
resistor, R6, left over and upon several rereads of
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