Psk

[kd1na]

Stephen,
I also use my K2-100 on psk.

I find that it is best to throttle down your power to 30 watts with the power control, then adjust you audio drive for just 30 watts out. I also turned audio compression off. I have received very good reports on IMD operating in this manner.

I know your not interested in interfaces but be advised the audio in and out of the K2 are not isolated.  If you are using a laptop computer then there should be no problem but on my desk top system I had to isolate the input and output audio to prevent ground loops.

Hope this helps.

73 and Happy Holidays.

Dave KD1NA
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[ac0h]

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Hash: SHA1

I do the same.

Set the power out at 30W then switch the meter to ALC and adjust the
audio level for NO ALC indication. Switch back to RF on the meter and it
just flickers the third LED while transmitting. Nothing but great
reports. I've got two 80mm computer case fans arranged diagonally on the
heat sink drawing air through the fins up and out. A small square of
double stick foam tape in each corner of both fans holds them tight.

I do use the rigblaster+ interface. I have been thinking of swapping out
my tired old SB Live sound card for an M-Audio Delta 44.

73

David Robertson wrote:

> Stephen,
> I also use my K2-100 on psk.
>
> I find that it is best to throttle down your power to 30 watts with the power control, then adjust you audio drive for just 30 watts out. I also turned audio compression off. I have received very good reports on IMD operating in this manner.
>
> I know your not interested in interfaces but be advised the audio in and out of the K2 are not isolated.  If you are using a laptop computer then there should be no problem but on my desk top system I had to isolate the input and output audio to prevent ground loops.
>
> Hope this helps.
>
> 73 and Happy Holidays.
>
> Dave KD1NA

- --
R. Kevin Stover, ACØH
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[Stephen Prior]

Thanks for the advice David, I shall do as you and Dave KD1NA suggest - at
least that way I suspect the setting of the output level from the soundcard
will be less critical.  With other radios I have owned such as the IC-7400,
it was recommended practice to have the power control at 100W and set the
output power on psk solely by audio input level - it was a bit touchy
sometimes!

I have a fan sitting on top of the heatsink, it's blowing down at the moment
and that seems to cut down the amount the noisy little fan comes on quite
noticeably.

73 Stephen



On 15/12/07 19:32, "R. Kevin Stover" <[hidden email]> wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> I do the same.
>
> Set the power out at 30W then switch the meter to ALC and adjust the
> audio level for NO ALC indication. Switch back to RF on the meter and it
> just flickers the third LED while transmitting. Nothing but great
> reports. I've got two 80mm computer case fans arranged diagonally on the
> heat sink drawing air through the fins up and out. A small square of
> double stick foam tape in each corner of both fans holds them tight.
>
> I do use the rigblaster+ interface. I have been thinking of swapping out
> my tired old SB Live sound card for an M-Audio Delta 44.
>
> 73
>
> David Robertson wrote:
>> Stephen,
>> I also use my K2-100 on psk.
>>
>> I find that it is best to throttle down your power to 30 watts with the power
>> control, then adjust you audio drive for just 30 watts out. I also turned
>> audio compression off. I have received very good reports on IMD operating in
>> this manner.
>>
>> I know your not interested in interfaces but be advised the audio in and out
>> of the K2 are not isolated.  If you are using a laptop computer then there
>> should be no problem but on my desk top system I had to isolate the input and
>> output audio to prevent ground loops.
>>
>> Hope this helps.
>>
>> 73 and Happy Holidays.
>>
>> Dave KD1NA
>
> - --
> R. Kevin Stover, ACØH
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.7 (MingW32)
> Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
>
> iD8DBQFHZCu311jxjloa2wsRAlZmAJ9R0ZrlrwS3fFyYaqkHPH2TALUZaACfTpBk
> lbCzMJr+JjjmaVT9lrocoIA=
> =zNSa
> -----END PGP SIGNATURE-----
>

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[Julian, G4ILO]

Stephen Prior wrote

Thanks for the advice David, I shall do as you and Dave KD1NA suggest - at
least that way I suspect the setting of the output level from the soundcard
will be less critical.  With other radios I have owned such as the IC-7400,
it was recommended practice to have the power control at 100W and set the
output power on psk solely by audio input level - it was a bit touchy
sometimes!

I have a fan sitting on top of the heatsink, it's blowing down at the moment
and that seems to cut down the amount the noisy little fan comes on quite
noticeably.

I'm surprised that no-one has mentioned it but I am sure one of the changes introduced way back when the revision 2 firmware was released for the K2 was to add a "soft" ALC in data mode that did not have an adverse effect on signal quality. Perhaps Lyle can comment since I am sure that he originally came up with a mod for this that was eventually incorporated in later production models.

I set the power control to 5W on my K2/10 and adjust the audio level so that 1 bar of ALC is showing. This gives a consistent output level that does not normally need to be readjusted even when changing bands.

[Stephen Prior]

Thanks Julian, that's interesting.  I haven't got to transmitting yet as I
find that I have lost the ssb tx audio somewhere!  I don't even have any
output using the microphone - I think I must have made a mistake on the mic
header where I have soldered the screened cable for the data audio in.

Thanks

73, Stephen G4SJP


On 17/12/07 12:06, "G4ILO" <[hidden email]> wrote:

>
>
> Stephen Prior wrote:
>>
>> Thanks for the advice David, I shall do as you and Dave KD1NA suggest - at
>> least that way I suspect the setting of the output level from the
>> soundcard
>> will be less critical.  With other radios I have owned such as the
>> IC-7400,
>> it was recommended practice to have the power control at 100W and set the
>> output power on psk solely by audio input level - it was a bit touchy
>> sometimes!
>>
>> I have a fan sitting on top of the heatsink, it's blowing down at the
>> moment
>> and that seems to cut down the amount the noisy little fan comes on quite
>> noticeably.
>>
> I'm surprised that no-one has mentioned it but I am sure one of the changes
> introduced way back when the revision 2 firmware was released for the K2 was
> to add a "soft" ALC in data mode that did not have an adverse effect on
> signal quality. Perhaps Lyle can comment since I am sure that he originally
> came up with a mod for this that was eventually incorporated in later
> production models.
>
> I set the power control to 5W on my K2/10 and adjust the audio level so that
> 1 bar of ALC is showing. This gives a consistent output level that does not
> normally need to be readjusted even when changing bands.
>
> -----
> Julian, G4ILO K2 s/n: 392  K3 s/n: ???
> G4ILO's Shack: www.g4ilo.com
> Zerobeat Ham Forums: www.zerobeat.net/smf

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[Stephen Prior]

Can anyone shed any light on this please?

I have connected tx and rx audio from/to the computer via isolation
transformers on both audio in and out.  Rx works fine.

However, I have hit a problem trying to get acceptable transmit audio
quality.  I have the K2 stripped back to 10W at the moment so am not using
my external KPA100 in order to remove that from the equation.  I am feeding
the audio from the computer via the isolating transformer straight to the
microphone header with the microphone removed.  I have turned the compressor
off in all modes.  I have no ALC showing and have tried the power control in
various positions.  The audio is extremely rough with various artifacts
spreading widely above and below the tx frequency.

I have the K2 feeding into a 100W Bird dummy load.  I have listened both
with my K1 with a few inches of wire as an antenna and my TS-480HX in the
car parked outside.  Same grotty received audio.

I have checked the carrier balance on the ssb board.  Although still audible
in the K1¹s receiver I have minimised it for usb and lsb.  I note that I can
eliminate it almost altogether for lsb, but then the level at usb is high.
So it¹s a compromise as I have read it would be.

I have tried both my desktop pc (a mac) and my Dell laptop (XP) - no
difference.  I have listened directly to the audio output from the computers
­ it sounds right.

I must have used psk31 on a dozen or more radios in the last ten years or
so, but never hit this severe a problem before.  Listening to my ssb speech
via the HM12 microphone, it doesn¹t sound great, but yet I am using the K1
to listen to it with so that¹s not too surprising.  I don¹t use ssb at all
except mobile, so have had no operating experience of the K2 in this mode.

I am wondering if the problem lies deeper somewhere.  I have googled, but
hit nothing useful.

Any thoughts would be much appreciated

Thanks and 73,

Stephen G4SJP


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[Don Wilhelm-4]

Stephen,

I believe you may be overdriving the microphone input of the K2.

Do you have any attenuation between your soundcard output and the K2
microphone input?  On the output (K2) side of the transformer connect a
series resistor about 10k in value and a 1k across the wires to the
microphone.  That will drop the soundcard level down to about 1/10 of
the soundcard output and keep from overdriving the microphone input.  
Reduce the 1k resistor if the soundcard still overloads the mic input of
the K2.

73,
Don W3FPR

Stephen Prior wrote:

> Can anyone shed any light on this please?
>
> I have connected tx and rx audio from/to the computer via isolation
> transformers on both audio in and out.  Rx works fine.
>
> However, I have hit a problem trying to get acceptable transmit audio
> quality.  I have the K2 stripped back to 10W at the moment so am not using
> my external KPA100 in order to remove that from the equation.  I am feeding
> the audio from the computer via the isolating transformer straight to the
> microphone header with the microphone removed.  I have turned the compressor
> off in all modes.  I have no ALC showing and have tried the power control in
> various positions.  The audio is extremely rough with various artifacts
> spreading widely above and below the tx frequency.
>
> I have the K2 feeding into a 100W Bird dummy load.  I have listened both
> with my K1 with a few inches of wire as an antenna and my TS-480HX in the
> car parked outside.  Same grotty received audio.
>
> I have checked the carrier balance on the ssb board.  Although still audible
> in the K1¹s receiver I have minimised it for usb and lsb.  I note that I can
> eliminate it almost altogether for lsb, but then the level at usb is high.
> So it¹s a compromise as I have read it would be.
>
> I have tried both my desktop pc (a mac) and my Dell laptop (XP) - no
> difference.  I have listened directly to the audio output from the computers
> ­ it sounds right.
>
> I must have used psk31 on a dozen or more radios in the last ten years or
> so, but never hit this severe a problem before.  Listening to my ssb speech
> via the HM12 microphone, it doesn¹t sound great, but yet I am using the K1
> to listen to it with so that¹s not too surprising.  I don¹t use ssb at all
> except mobile, so have had no operating experience of the K2 in this mode.
>
> I am wondering if the problem lies deeper somewhere.  I have googled, but
> hit nothing useful.
>
> Any thoughts would be much appreciated
>
> Thanks and 73,
>
> Stephen G4SJP
>
>
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>
>  

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[Stephen Prior]

Don

Well, once again you've come up trumps!  I did as you suggested but have
ended up finally with a 1:20 potential divider and the audio sounds much
like it should do, although I feel it's not as good as it was with my
TS-480HX but I am being very picky!  I just got a -22dB IMD report from a DJ
on 40m in a noisy band so it's at least adequate.  I am (just) not showing
any ALC and have set the output power control to 30W.  So far I have been
using LSB, now I need to set up those RTTY filters properly!

Thanks again, and have a great Christmas!

73 Stephen


On 18/12/07 14:13, "Don Wilhelm" <[hidden email]> wrote:

> Stephen,
>
> I believe you may be overdriving the microphone input of the K2.
>
> Do you have any attenuation between your soundcard output and the K2
> microphone input?  On the output (K2) side of the transformer connect a
> series resistor about 10k in value and a 1k across the wires to the
> microphone.  That will drop the soundcard level down to about 1/10 of
> the soundcard output and keep from overdriving the microphone input.
> Reduce the 1k resistor if the soundcard still overloads the mic input of
> the K2.
>
> 73,
> Don W3FPR
>
> Stephen Prior wrote:
>> Can anyone shed any light on this please?
>>
>> I have connected tx and rx audio from/to the computer via isolation
>> transformers on both audio in and out.  Rx works fine.
>>
>> However, I have hit a problem trying to get acceptable transmit audio
>> quality.  I have the K2 stripped back to 10W at the moment so am not using
>> my external KPA100 in order to remove that from the equation.  I am feeding
>> the audio from the computer via the isolating transformer straight to the
>> microphone header with the microphone removed.  I have turned the compressor
>> off in all modes.  I have no ALC showing and have tried the power control in
>> various positions.  The audio is extremely rough with various artifacts
>> spreading widely above and below the tx frequency.
>>
>> I have the K2 feeding into a 100W Bird dummy load.  I have listened both
>> with my K1 with a few inches of wire as an antenna and my TS-480HX in the
>> car parked outside.  Same grotty received audio.
>>
>> I have checked the carrier balance on the ssb board.  Although still audible
>> in the K1¹s receiver I have minimised it for usb and lsb.  I note that I can
>> eliminate it almost altogether for lsb, but then the level at usb is high.
>> So it¹s a compromise as I have read it would be.
>>
>> I have tried both my desktop pc (a mac) and my Dell laptop (XP) - no
>> difference.  I have listened directly to the audio output from the computers
>> ­ it sounds right.
>>
>> I must have used psk31 on a dozen or more radios in the last ten years or
>> so, but never hit this severe a problem before.  Listening to my ssb speech
>> via the HM12 microphone, it doesn¹t sound great, but yet I am using the K1
>> to listen to it with so that¹s not too surprising.  I don¹t use ssb at all
>> except mobile, so have had no operating experience of the K2 in this mode.
>>
>> I am wondering if the problem lies deeper somewhere.  I have googled, but
>> hit nothing useful.
>>
>> Any thoughts would be much appreciated
>>
>> Thanks and 73,
>>
>> Stephen G4SJP
>>
>>
>> _______________________________________________
>> Elecraft mailing list
>> Post to: [hidden email]
>> You must be a subscriber to post to the list.
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>>
>>
>>  
>

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[rkayakr]

Stephen

  When I do PSK with my K2 (or K3) I set the amplifier power at max value and then drive it with just enough audio signal to get 20-30 watts out. This yields a signal with -29 to -30 db IMD on my KK7UQ IMD meter.

   Hope this helps
        Bob
          KD8CGH
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