KAT100 woes... Time to 'fess up...

[Tom Hammond-3]

Hi Folks:

Man, I just HATE it when I have to come clean... but here goes... mainly
for the benefit of anyone else out there who runs into the same problem...

About three weeks ago, the day before left on a trip, we had a pretty
'healthy' thunder storm track right over the top of N0SS Central.

When I heard the first thunder clap, I legged it out to the shack In the
garage) and started disconnecting coaxes like a mad man...

I had just(!) managed to get the last coax connector DISconnected and moved
away from the rig(s) when an all too close bolt of lightning struck.
Fortunately I wasn't touching anything (by about 1/2 second!) when it hit
and I heard/saw a nice arc between the shell of one coax connector and the
nearby ground.

I finished up my work and got the heck out of the shack, vowing to return a
bit later.

Well, things conspired to keep me out of the shack until the next week when
I'd returned from my trip.

I reconnected the coaxes, AND the K2 and all appendages. Turned on the rig,
hit TUNE and listened as the KAT100 went through its paces, tuning up on 20M.

Everything SOUNDED just as it should have sounded. The ATU took the right
amount of time, to tune, and the ratta-tat-tat of the relays made the right
rhythm. The K2/100 put out 100W into the beam, and all the other (external)
meters indicated perfect operation.

The one thing which WASN'T right was that the K2's LCD display indicated an
SWR of 9.9:1 while the ATU tuned, and NOT ONE of the LEDs on the front of
the KAT100 illuminated while it tuned up. Something was obviously wrong!

I set the K2 to 5W, the KAT100 to CAL mode and pressed TUNE in an effort to
see what things looked like there. THIS time the K2 LCD display indicated
2W output and an indicated SWR of EITHER 1:1 or 9.9:1, kinda randomly
changing between the two SWRs with each successive press of TUNE. And, this
time, the LEDs on the front of the KAT100 were ALL LIT!!!

I then inserted a second ATU in-line, so I could create a varying SWR of
known quantity, so I could monitor what the KAT100 showed. With an
'inserted' of 1:1, the KAT100 generally indicated NO LEDS (or 1:1, I
guess). With virtually ANY other inserted SWR from the 2nd ATU, ALL of the
KAT100 LEDs illuminated.

I checked the 1N5711's in the KAT100 bridge. They were good and working as
expected. In fact, everything SEEMED to be working properly... other than
the weird LCD and LED indications.

I asked the experts... they'd never seen anything such as this, but several
were certain the nearby lightning strike had 'farkled' something somewhere.

I obtained a new PIC for the KAT100 and also a number of TPICs (LED
drivers, etc.) as a precaution that some of them had been 'taken out' as well.

Replaced the PIC in the KAT100 and nothing changed.

Did a hard RESET of both the K2 and the KAT100, but to no avail.

Then... as I was about the disconnect the K2/100 from everything in
preparation to taking it out back and using is as target practice... there
it was... the culprit...

It seems that, during my haste to get everything reconnected (remember,
somewhere about 30 lines above in this treatise)... I'm managed to connect
the RF OUT from the KPA100 to the ANT1 jack on the KAT100 and the coax from
the external antenna switch to the RF IN jack on the KAT100... in short, I
had the RF IN and ANT1 connections reversed!!!!!

Swapped these two connections on the back of the KAT100 and EVERYTHING
WORKED PROPERLY!!!

So now my conscience is clear... I've confessed to my transgressions... and
done all sorts of penance to the RF gods. And I'm sitting here baring my
soul to you so you might not make the same mistake!!!

ALWAYS DOUBLE-, no... TRIPLE-CHECK YOUR EXTERNAL CONNECTIONS!

And, if your KAT100 seems to tune properly but INDICATED weirdly, don't
jump to conclusions... the problem may be man-made rather than the fault of
Mother Nature.

73,

Tom Hammond   N0SS

p.s.

I find it very interesting that the KAT100, regardless of the fact that the
I/O lines had been crossed, CONTINUED to PROPERLY TUNE TO A (verified) 1:1
SWR, even though everything else was seeing 9.9:1 by virtue of the reversed
connections. That's some ATU there!

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[Jim Younce]

Tom:

A very nice read.  Confession is good for the soul.  I must confess I was
building a KPA100/KAT100 in an EC2 enclosure for a fellow not long ago and
when trying to calibrate the output meter I never could get it the right
indications on the wattmeter and the max I could get out on my KPA100
looking at an external meter was 20 watts.  I replaced a couple of chips and
still no joy.  I finally realized that I was using the Tune button on the K2
and had a KAT100 connected also.  The firmware was doing its job in reducing
the power to 20 watts for tune up.  I connected a straight key and keyed the
unit and adjusted my power to 100 watts and then set the K2 display
correctly...LOL  One other thing was that no matter where I set the RF Power
control it always put out 20 watts just like it was supposed to do.
Sometimes and recently more often than I care to admit, the machines are
smarter than I am....LOL

73

Jim  K4ZM


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[Jim Sheldon]

Hi Tom, and all,
Glad to see that I'm not the only one to do things like that.  Mine occurred
this past Saturday. I bought a KX1 and it arrived Friday, so naturally, I
dropped everything and started building.  30 meter board first, then the ATU
to have them ready when the time came.  After that, I built the KX1 itself.
First tests passed fine, and I finished the build Saturday afternoon and it
passed the final test (power output was a little low, but not enough to
worry me.)  I then installed the ATU and did the SWR and Power Calibrations.
This also checked out fine.  Next, I removed the ATU and installed the 30
meter board.  When I attempted the alignment, the whole radio was deaf as a
post.  None of the trimmers appeared to do anything, and I had an NGEN board
hooked up to give it lots of noise to chew on.  

After tearing out what little hair I have left, I got out the desoldering
equipment and prepared to remove the 30 meter board, expecting that I might
have busted on or more of those micro miniature RF chokes.  Just before
clipping the first wire, the light dawned - I hadn't put the jumper across
pins 1 and 3 of the antenna header that routes RF to and from the ATU.
Since the ATU was out of the radio, without that jumper, there was no RF
path from the BNC connector to the rest of the rig.  No bloody wonder it
didn't hear anything.  I grabbed an old resistor lead and quickly replaced
the jumper.  Turned on the NGEN again and BINGO, all trimmers actually did
something.  I re-aligned 20 and 40 as called out in the manual, and then did
the 30 meter alignment.  Put the ATU back in and ran the final tests.  The
whole thing worked like it was supposed to.

Note to anyone that hasn't built a KX1 yet and plans on it, REMEMBER THAT
JUMPER when removing the ATU from the radio if you plan on leaving it out
for any reason.  

I wasn't going to tell anyone about it, but since Tom "fessed up" to his
error, I figured I ought to as well if it might save someone else a problem
in the future.  The need for the jumper is actually mentioned in the book,
and I HAD read it.  Just forgot it in my excitement to get my KX1 on the
air.  

Oh yeah, first contact with the KX1 was a DX station (PA600GOES - yeah I
know it's a weird call that's pa six hundred goes) in the Netherlands.  Got
a 539 on 20 meters - KX1 and a CushCraft A3S tri bander up 25 feet.

Jim Sheldon, W0EB
Wichita, KS
K2 #4338
KX1 #1268

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Tom Hammond
> Sent: Wednesday, October 19, 2005 10:00 AM
> To: [hidden email]
> Subject: [Elecraft] KAT100 woes... Time to 'fess up...
>
>
> Hi Folks:
>
> Man, I just HATE it when I have to come clean... but here
> goes... mainly
> for the benefit of anyone else out there who runs into the
> same problem...

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[Steven Pituch]

Hi all,
Been there; done that.

After I finally figured out what I had done and then checked the equipment,
I was very thankful Elecraft makes rugged equipment that can often withstand
some unintentional abuse.

Steve, W2MY



-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Tom Hammond
Subject: [Elecraft] KAT100 woes... Time to 'fess up...

It seems that, during my haste to get everything reconnected (remember,
somewhere about 30 lines above in this treatise)... I'm managed to connect
the RF OUT from the KPA100 to the ANT1 jack on the KAT100 and the coax from
the external antenna switch to the RF IN jack on the KAT100... in short, I
had the RF IN and ANT1 connections reversed!!!!!

Swapped these two connections on the back of the KAT100 and EVERYTHING
WORKED PROPERLY!!!


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Gee Tom,

I did the same thing earlier this year, but I wasn't
going to tell on myself.  Now, I feel I gotta give you
emotional support for the trauma you've been through.
I figured it out before ripping everything apart.  

Lee - K0WA


Common sense is in short supply - get some and use it.
If you can't find any common sense, ask for help from
somebody that has some common sense. - Lee Buller
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[tom.w3qs]

I must say that I have been battling this issue for years, especially since
my TV is now a _home entertainment system_ with more cables and wires than
my 1950's ham shack.

I invested in a Brother label maker.  It makes nice 1/4 inch plastic labels
that now adorn every wire in the house with either what it is or where it
goes, ie. Vertical, Beam, VCR Input, DVD Output, etc.  Piece of cake to
reassemble the wiring.

Tom, W3QS



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[Bill Coleman-2]

On Oct 19, 2005, at 10:59 AM, Tom Hammond wrote:

> When I heard the first thunder clap, I legged it out to the shack  
> In the garage) and started disconnecting coaxes like a mad man...
>
> I had just(!) managed to get the last coax connector DISconnected  
> and moved away from the rig(s) when an all too close bolt of  
> lightning struck. Fortunately I wasn't touching anything (by about  
> 1/2 second!) when it hit and I heard/saw a nice arc between the  
> shell of one coax connector and the nearby ground.

This is the problem, Tom. You don't need to disconnect those coaxes  
as much as GROUND them.

I have all my antennas passing through a grounding switch, and I keep  
it switched to the grounded position when the station is not in use.

The only time I've had lightning damage was when I had my antennas  
disconnected. That was during FD 1993 on Sunday, when all my gear was  
in the car and I was taking a nap on the sofa. I still have a piece  
of test equipment that needs repair from that strike.

Bill Coleman, AA4LR, PP-ASEL        Mail: [hidden email]
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901

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[Ward Willats-3]

>in short, I had the RF IN and ANT1 connections reversed!!!!!
>
>

Ah yes, I seem to remember whining on this very reflector when my
brand-new K2 didn't hear very well during initial alignment. Turns
out it helps if you flip the coax switch over to the main antenna
from the dummy load.

-- Ward / KG6HAF
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