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K2-100 Parasitic

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walter renner

K2-100 Parasitic

While reading a post by Stan, W5EWA and his experince with a problems on the
40 meter band with parasitic occilations, I realized that I was also having
the same thing happening to my setup. When using the K2-100 with the KAT100
tuner on the 40 meter band it caused the tuner to act erratic on high power.
It would work fine on the low power setting, and would work fine with tuned
antennas cut for the band, but when using my 204 foot open wire center fed
antenna the tuner would go nut's and cause the radio to reset. Also at times
cause some of the presets in the K2 to change when it reset. I could bypass
the KAT100, and using my home brew tuner the parasitic would not show up.
Tom Hammond, N0SS offered a possible soultion for Stan, so I e-mailed Tom to
see what help he could offer.
Tom sent me a proposed modifcation to the KAP-100 amp. the required moving
the RFC10 that's mounted on the SO-239 over so it is not covering the open
slot on the PC board. The modifcation was easy to do and cured the problem
in my setup. In my case the RFC was only moved about 1/8", which seemed
rather insigficant at the time, but it sure made things work in my K2100 -
KAP100 combo.
Thanks Tom.
Kurt K0ARO
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Ken Wagner K3IU

K2-100 Parasitic

I also have experienced this problem on 3 different K2/100s. I had moved the
my KAT100 a couple feet from the K2/100 which reduced the magnitude of the
problem. Tuning on low power prevented the problem. After talking to Tom,
n0ss, I moved RFC-10 further away from the RF connector (J2). I'm not sure
exactly how far I moved it but is was probably 2 or 3 mm. I no longer have
the problem. I have moved the KAT100 back beneath the K2/100 and now
experience no problems tuning with high power on 40 meters. I have sent the
info on this to the present owner of one of the other K2/100s that displayed
this problem and will make this "mod" to the third one in 2 or 3 weeks when
the local owner returns to town. After I get my hands on the local one, I'll
put a note on the reflector about the results.

I really don't know exactly what causes the problem or why moving that RFC a
silly little millimeter or 2 corrects the problem, but it worked here!

73,
Ken K3IU

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of walter renner
Sent: Sunday, May 14, 2006 7:54 AM
To: ElecraftList
Subject: [Elecraft] K2-100 Parasitic

While reading a post by Stan, W5EWA and his experince with a problems on the
40 meter band with parasitic occilations, I realized that I was also having
the same thing happening to my setup. When using the K2-100 with the KAT100
tuner on the 40 meter band it caused the tuner to act erratic on high power.

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John Huffman-2

Re: K2-100 Parasitic

In reply to this post by walter renner

Kurt -

I've had the same problem. I had assumed RF was getting into my setup on 40
meters. The KAT100 would not find a match and only one LED would light up at a
time. It often caused the KDPS2 to disconnect requiring a shut off and on to
get it back.

Separating the KAT100 from the K2/100 by a couple of feet was a temporary fix.

I'll give moving RFC10 a try. Did you move it back away from the back panel?
Did you move it closer to T4 on the other side of the board? Did you need to
readjust C1 for SWR null?

73 de K1ESE
John

> Tom sent me a proposed modifcation to the KAP-100 amp. the required moving the
> RFC10 that's mounted on the SO-239 over so it is not covering the open slot on
> the PC board. The modifcation was easy to do and cured the problem in my
> setup. In my case the RFC was only moved about 1/8", which seemed rather
> insigficant at the time, but it sure made things work in my K2100 - KAP100
> combo.

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Tom Althoff

Re: K2-100 Parasitic

In reply to this post by Ken Wagner K3IU

Add me to the list of people experiencing the K2/KPA-100/KAT-100 40M high
power reset problem.

Since my KAT-100 is built into the base of my K2/100 I do not have the
option of moving the KAT-100 farther from the K2/100.

One observation I made back when I was trying to track the problem down was
that it did NOT seem to happen when I ran on a 12V car battery on my desktop
but DID happen when I used my Astron 20A switching supply. It was not a
conclusive test but I'll try again next week.

How many others who are experiencing this erratic 40M behavior (resets the
K2 etc) are also using switching supplies?

Anyone having problems with a K2/100 and KAT-100 combo ONLY on 40M please
contact me off-list and I'll keep track of all those who are affected by
this problem. One person is a fluke, two people is a coincidence, three
people is a trend and four or more people is a problematic symptom that
needs looking into.

- Tom K2TA

----- Original Message -----
From: "Ken K3IU" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, May 14, 2006 8:28 AM
Subject: [Elecraft] K2-100 Parasitic

> I also have experienced this problem on 3 different K2/100s. I had moved
the
> my KAT100 a couple feet from the K2/100 which reduced the magnitude of the
> problem. Tuning on low power prevented the problem. After talking to Tom,
> n0ss, I moved RFC-10 further away from the RF connector (J2). I'm not sure
> exactly how far I moved it but is was probably 2 or 3 mm. I no longer have
> the problem. I have moved the KAT100 back beneath the K2/100 and now
> experience no problems tuning with high power on 40 meters. I have sent
the
> info on this to the present owner of one of the other K2/100s that
displayed
> this problem and will make this "mod" to the third one in 2 or 3 weeks
when
> the local owner returns to town. After I get my hands on the local one,
I'll
> put a note on the reflector about the results.
>
> I really don't know exactly what causes the problem or why moving that RFC
a

> silly little millimeter or 2 corrects the problem, but it worked here!
>
> 73,
> Ken K3IU
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of walter renner
> Sent: Sunday, May 14, 2006 7:54 AM
> To: ElecraftList
> Subject: [Elecraft] K2-100 Parasitic
>
> While reading a post by Stan, W5EWA and his experince with a problems on

the
> 40 meter band with parasitic occilations, I realized that I was also
having
> the same thing happening to my setup. When using the K2-100 with the
KAT100
> tuner on the 40 meter band it caused the tuner to act erratic on high
power.

>
>
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

srife

RE: K2-100 Parasitic

Tom, have you done the N0SS RFC-10 mod yet?

Stan Rife
W5EWA
Houston, TX
K2 S/N 4216

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Tom Althoff
Sent: Sunday, May 14, 2006 8:42 AM
To: [hidden email]
Subject: Re: [Elecraft] K2-100 Parasitic

Add me to the list of people experiencing the K2/KPA-100/KAT-100 40M high
power reset problem.

Since my KAT-100 is built into the base of my K2/100 I do not have the
option of moving the KAT-100 farther from the K2/100.

One observation I made back when I was trying to track the problem down was
that it did NOT seem to happen when I ran on a 12V car battery on my desktop
but DID happen when I used my Astron 20A switching supply. It was not a
conclusive test but I'll try again next week.

How many others who are experiencing this erratic 40M behavior (resets the
K2 etc) are also using switching supplies?

Anyone having problems with a K2/100 and KAT-100 combo ONLY on 40M please
contact me off-list and I'll keep track of all those who are affected by
this problem. One person is a fluke, two people is a coincidence, three
people is a trend and four or more people is a problematic symptom that
needs looking into.

- Tom K2TA

----- Original Message -----
From: "Ken K3IU" <[hidden email]>
To: <[hidden email]>
Sent: Sunday, May 14, 2006 8:28 AM
Subject: [Elecraft] K2-100 Parasitic

> I also have experienced this problem on 3 different K2/100s. I had moved
the
> my KAT100 a couple feet from the K2/100 which reduced the magnitude of the
> problem. Tuning on low power prevented the problem. After talking to Tom,
> n0ss, I moved RFC-10 further away from the RF connector (J2). I'm not sure
> exactly how far I moved it but is was probably 2 or 3 mm. I no longer have
> the problem. I have moved the KAT100 back beneath the K2/100 and now
> experience no problems tuning with high power on 40 meters. I have sent
the
> info on this to the present owner of one of the other K2/100s that
displayed
> this problem and will make this "mod" to the third one in 2 or 3 weeks
when
> the local owner returns to town. After I get my hands on the local one,
I'll
> put a note on the reflector about the results.
>
> I really don't know exactly what causes the problem or why moving that RFC
a

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Vic K2VCO

RE: K2-100 Parasitic

In reply to this post by walter renner

I remember this problem from the early days of the KPA100, although not
necessarily in connection with the KAT100. I believe there was a
builder's alert issued about the RF choke location, but I was unable to
find it on the Elecraft Web site.

If the KPA100 is old enough that it does not have the side grounding
clips and reconfigured shield, there is a modification kit at
<http://www.elecraft.com/order_form_parts.htm> called KPA100SHLDKT.
This change was included in KPA100's shipped after June 2003, according
to the parts list description. The reconfigured shield has a smaller
gap near the SO239 and the RF choke which I believe was intended to fix
this problem.

Although I don't recall exactly, I think the suggestion in the original
Builder's Alert was to mount the RF choke away from the hole in the
shield and as close to the chassis as possible.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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