Elecraft › [K2]

K2 Build # 653 SSB issues.

Classic

List

Threaded

4 messages Options

Nidge_(G0NIG)

K2 Build # 653 SSB issues.

Hi All

I have in my possession a K2 with the following options.

KPA100, KSB2, K160RX, KNB2, KDSP2, .

I’m not the original builder of this example and the source of the original builder is a little vague.

So far I have done a complete reset of the radio, fine tuned the alignment of the bandpass filters
in the base, aligned the CW and SSB filters. As of yet I haven’t looked inside the KPA100 option, which
is mounted internally.

There are a few issues with this radio but the one I’m concentrating on at the moment is to do
with the SSB performance in conjunction with the KPA100. These can be seen below:

160m – Using the tune button produces 100Watts, SSB the radio folds back to about 5 Watts.

80m – All seems fine.

40m – When the power control is advanced to engage the KPA100 and the tx is peaked with a whistle the radio goes
into self oscillation, no issues on CW.

30m – Display reads high current and the TX folds back to about 5 Watts. No issues noted when the KPA100 is
disengaged.

20m - All appears to be fine.

17m – Display reads high current and the TX folds back to about 5 Watts. No issues noted when the KPA100 is
disengaged.

15m – All appears to be OK

12m – All appears to be OK, max TX power is about 70Watts

10m – All appears to be OK, max TX power is about 65-70Watts.

There is an intermittent issue when stepping through the bands up to 15m/12m/10m when there is no TX output
or receive. Switching the radio off and back on seems to cure this.

Any advice gratefully received.

Nidge (G0NIG)

IO93dv

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Don Wilhelm-4

Re: K2 Build # 653 SSB issues.

Nidge,

First help me establish the level of your KPA100.
Do you have blue toroids at RFC1 and L16? If so, look at the value of
C31 - it should be 0.22 uF. If C31 is 0.033 uF (33nF) it must be changed.

If you have red toroids at L15 and L16, then your first step is to
install KPA100UPKT.

There are other possibilities with the shield. The gap at the SO-230
jack should be less than 3mm, you should have solder lugs connecting the
SO-239 jack directly to the shield, and the shield should have 3 clips 2
of which should contact unpainted metal on the base K2 side panels. If
that is not the case, then you must update the shield kit. Yes, the
KPA100 can oscillate if it is not properly shielded from the circuits in
the base K2.

73,
Don W3FPR

On 6/17/2011 7:20 AM, Nigel (Nidge) Smith wrote:

> Hi All
>
> I have in my possession a K2 with the following options.
>
> KPA100, KSB2, K160RX, KNB2, KDSP2, .
>
> I’m not the original builder of this example and the source of the original builder is a little vague.
>
> So far I have done a complete reset of the radio, fine tuned the alignment of the bandpass filters
> in the base, aligned the CW and SSB filters. As of yet I haven’t looked inside the KPA100 option, which
> is mounted internally.
>
> There are a few issues with this radio but the one I’m concentrating on at the moment is to do
> with the SSB performance in conjunction with the KPA100. These can be seen below:
>
> 160m – Using the tune button produces 100Watts, SSB the radio folds back to about 5 Watts.
>
> 80m – All seems fine.
>
> 40m – When the power control is advanced to engage the KPA100 and the tx is peaked with a whistle the radio goes
> into self oscillation, no issues on CW.
>
> 30m – Display reads high current and the TX folds back to about 5 Watts. No issues noted when the KPA100 is
> disengaged.
>
> 20m - All appears to be fine.
>
> 17m – Display reads high current and the TX folds back to about 5 Watts. No issues noted when the KPA100 is
> disengaged.
>
> 15m – All appears to be OK
>
> 12m – All appears to be OK, max TX power is about 70Watts
>
> 10m – All appears to be OK, max TX power is about 65-70Watts.
>
> There is an intermittent issue when stepping through the bands up to 15m/12m/10m when there is no TX output
> or receive. Switching the radio off and back on seems to cure this.
>
> Any advice gratefully received.
>
> Nidge (G0NIG)
>
> IO93dv
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Nidge_(G0NIG)

Re: K2 Build # 653 SSB issues.

Hi Don, and thanks for the very quick response.

I've just removed the KPA100 from the base and removed
the cover.

RFC1 appears to be a largish black choke (not torroid) with "101" printed on
it.

L15 and L16 are Red Torriods, therefore it would appear that
KPA100UPKT needs to be purchased and installed.

The solder lug is connected to the back panel of the KPA100,
which I presume would be connected to the shield by the spring
contacts on the shield.

As I understand it the previous owner had the kit built for them by
a third party. He has assured me he purchased the relavent upgrades
but it would appear they were not installed. This appears to be the
same with respect to the BFO upgrades and others.

I have downloaded the manual for the KPA100 and will go over the
installation and alignment, in its current none upgraded guise, with a
fine tooth comb and ensure all test measurements are correct.

Again thanks for the very quick response.

Regards

Nidge (G0NIG)

IO93dv
----- Original Message -----
From: "Don Wilhelm" <[hidden email]>
To: "Nigel (Nidge) Smith" <[hidden email]>
Cc: <[hidden email]>
Sent: Friday, June 17, 2011 1:02 PM
Subject: Re: [Elecraft] K2 Build # 653 SSB issues.

> Nidge,
>
> First help me establish the level of your KPA100.
> Do you have blue toroids at RFC1 and L16? If so, look at the value of
> C31 - it should be 0.22 uF. If C31 is 0.033 uF (33nF) it must be changed.
>
> If you have red toroids at L15 and L16, then your first step is to install
> KPA100UPKT.
>
> There are other possibilities with the shield. The gap at the SO-230 jack
> should be less than 3mm, you should have solder lugs connecting the SO-239
> jack directly to the shield, and the shield should have 3 clips 2 of which
> should contact unpainted metal on the base K2 side panels. If that is not
> the case, then you must update the shield kit. Yes, the KPA100 can
> oscillate if it is not properly shielded from the circuits in the base K2.
>
> 73,
> Don W3FPR
>
> On 6/17/2011 7:20 AM, Nigel (Nidge) Smith wrote:
>> Hi All
>>
>> I have in my possession a K2 with the following options.
>>
>> KPA100, KSB2, K160RX, KNB2, KDSP2, .
>>
>> I’m not the original builder of this example and the source of the
>> original builder is a little vague.
>>
>> So far I have done a complete reset of the radio, fine tuned the
>> alignment of the bandpass filters
>> in the base, aligned the CW and SSB filters. As of yet I haven’t looked
>> inside the KPA100 option, which
>> is mounted internally.
>>
>> There are a few issues with this radio but the one I’m concentrating on
>> at the moment is to do
>> with the SSB performance in conjunction with the KPA100. These can be
>> seen below:
>>
>> 160m – Using the tune button produces 100Watts, SSB the radio folds back
>> to about 5 Watts.
>>
>> 80m – All seems fine.
>>
>> 40m – When the power control is advanced to engage the KPA100 and the tx
>> is peaked with a whistle the radio goes
>> into self oscillation, no issues on CW.
>>
>> 30m – Display reads high current and the TX folds back to about 5 Watts.
>> No issues noted when the KPA100 is
>> disengaged.
>>
>> 20m - All appears to be fine.
>>
>> 17m – Display reads high current and the TX folds back to about 5 Watts.
>> No issues noted when the KPA100 is
>> disengaged.
>>
>> 15m – All appears to be OK
>>
>> 12m – All appears to be OK, max TX power is about 70Watts
>>
>> 10m – All appears to be OK, max TX power is about 65-70Watts.
>>
>> There is an intermittent issue when stepping through the bands up to
>> 15m/12m/10m when there is no TX output
>> or receive. Switching the radio off and back on seems to cure this.
>>
>> Any advice gratefully received.
>>
>> Nidge (G0NIG)
>>
>> IO93dv
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1382 / Virus Database: 1513/3709 - Release Date: 06/17/11
>

Don Wilhelm-4

Re: K2 Build # 653 SSB issues.

Nidge,

From your description, you have the older KPA100 - the changes are in
the T/R switch area, and the reason for the change was to cure potential
oscillation.

Take a look at the instructions for the KPA100SHLDKT to see how the two
solder lugs connect the SO-239 directly to the shield. If you do not
have those, install some right away and see if that tames things.
Also look carefully at the shield notch at the SO-239 location - it
should be a 2 step notch. The left end (looking at the shield with the
KPA100 upside-down) of the notch should just barely clear the SO-239 and
its mounting nuts, while the right end is notched deeper to clear the 2D
connector when it is placed on the base K2. If the notch is a single
step notch, it is the older shield and should be updated.

73

On 6/17/2011 8:32 AM, Nigel (Nidge) Smith wrote:

> Hi Don, and thanks for the very quick response.
>
> I've just removed the KPA100 from the base and removed
> the cover.
>
> RFC1 appears to be a largish black choke (not torroid) with "101" printed on
> it.
>
> L15 and L16 are Red Torriods, therefore it would appear that
> KPA100UPKT needs to be purchased and installed.
>
> The solder lug is connected to the back panel of the KPA100,
> which I presume would be connected to the shield by the spring
> contacts on the shield.
>
> As I understand it the previous owner had the kit built for them by
> a third party. He has assured me he purchased the relavent upgrades
> but it would appear they were not installed. This appears to be the
> same with respect to the BFO upgrades and others.
>
> I have downloaded the manual for the KPA100 and will go over the
> installation and alignment, in its current none upgraded guise, with a
> fine tooth comb and ensure all test measurements are correct.
>
> Again thanks for the very quick response.
>
> Regards
>
> Nidge (G0NIG)
>
> IO93dv
> ----- Original Message -----
> From: "Don Wilhelm"<[hidden email]>
> To: "Nigel (Nidge) Smith"<[hidden email]>
> Cc:<[hidden email]>
> Sent: Friday, June 17, 2011 1:02 PM
> Subject: Re: [Elecraft] K2 Build # 653 SSB issues.
>
>
>> Nidge,
>>
>> First help me establish the level of your KPA100.
>> Do you have blue toroids at RFC1 and L16? If so, look at the value of
>> C31 - it should be 0.22 uF. If C31 is 0.033 uF (33nF) it must be changed.
>>
>> If you have red toroids at L15 and L16, then your first step is to install
>> KPA100UPKT.
>>
>> There are other possibilities with the shield. The gap at the SO-230 jack
>> should be less than 3mm, you should have solder lugs connecting the SO-239
>> jack directly to the shield, and the shield should have 3 clips 2 of which
>> should contact unpainted metal on the base K2 side panels. If that is not
>> the case, then you must update the shield kit. Yes, the KPA100 can
>> oscillate if it is not properly shielded from the circuits in the base K2.
>>
>> 73,
>> Don W3FPR
>>
>> On 6/17/2011 7:20 AM, Nigel (Nidge) Smith wrote:
>>> Hi All
>>>
>>> I have in my possession a K2 with the following options.
>>>
>>> KPA100, KSB2, K160RX, KNB2, KDSP2, .
>>>
>>> I’m not the original builder of this example and the source of the
>>> original builder is a little vague.
>>>
>>> So far I have done a complete reset of the radio, fine tuned the
>>> alignment of the bandpass filters
>>> in the base, aligned the CW and SSB filters. As of yet I haven’t looked
>>> inside the KPA100 option, which
>>> is mounted internally.
>>>
>>> There are a few issues with this radio but the one I’m concentrating on
>>> at the moment is to do
>>> with the SSB performance in conjunction with the KPA100. These can be
>>> seen below:
>>>
>>> 160m – Using the tune button produces 100Watts, SSB the radio folds back
>>> to about 5 Watts.
>>>
>>> 80m – All seems fine.
>>>
>>> 40m – When the power control is advanced to engage the KPA100 and the tx
>>> is peaked with a whistle the radio goes
>>> into self oscillation, no issues on CW.
>>>
>>> 30m – Display reads high current and the TX folds back to about 5 Watts.
>>> No issues noted when the KPA100 is
>>> disengaged.
>>>
>>> 20m - All appears to be fine.
>>>
>>> 17m – Display reads high current and the TX folds back to about 5 Watts.
>>> No issues noted when the KPA100 is
>>> disengaged.
>>>
>>> 15m – All appears to be OK
>>>
>>> 12m – All appears to be OK, max TX power is about 70Watts
>>>
>>> 10m – All appears to be OK, max TX power is about 65-70Watts.
>>>
>>> There is an intermittent issue when stepping through the bands up to
>>> 15m/12m/10m when there is no TX output
>>> or receive. Switching the radio off and back on seems to cure this.
>>>
>>> Any advice gratefully received.
>>>
>>> Nidge (G0NIG)
>>>
>>> IO93dv
>>>
>>>
>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>
>> -----
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 10.0.1382 / Virus Database: 1513/3709 - Release Date: 06/17/11
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html