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K2: PSK-31 Power Settings

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jperelst

K2: PSK-31 Power Settings

This may have been answered before, but I couldn't find any search terms that brought up the info I was looking for.

What power and volume settings do people use for PSK-31?

I have a 100w K2 and I use a SignaLink going into the K2's mic jack. The standard approach that has always been recommended to me is to set the rig's power to full power and then control output power with the transmit volume setting on the SignaLink. I set my SignaLink transmit volume so that the RF level on the K2 shows about 30 watts (essentially 3 tick marks) when I'm transmitting.

I've noticed that the K2 gets very hot this way, with the fan going to high high speed.

Is that the right way to run the K2, or should I be doing something differently?

Thanks.

Jon
KB1QBZ
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Don Wilhelm-4

Re: K2: PSK-31 Power Settings

Jon,

I would recommend setting the power to 30 watts. Then hold DISPLAY to
change the metering to ALC - adjust the audio up just to the point where
there is no ALC indication (adjust until you see ALC bars and then back
off until there are none). That should give you a cleaner signal and
better control of the output level. Since the gain of the K2 transmit
chain varies from band to band, you may have to check the audio drive
level again when changing to a different band. For further explanation,
read on.

For those using the K3 instead of the K2, set the audio to indicate
between 4 and 5 bars on the ALC meter - the low end of the "ALC meter"
scale on the K3 does not indicate ALC at all, but is more like a VU
meter - ALC action starts at the 5th bar. Let the K3 control the power
out with its normal control mechanism.

The K2 and K3 control power in a different way than many other
transceivers, in that they monitor the level of the output signal, and
if that level is less than the level requested, the drive will be
increased in an attempt to increase the power.
So the likely result of you setting the K2 power to 100 watts and using
the audio level to control the power results in the K2 trying to
increase the drive to make the peaks as close to 100 watts as possible -
of course, it can't make it because you have decreased the audio. but
using the K2 that way will increase the residual level of the suppressed
carrier and cause other parameters of the normal power control mechanism
to "do strange things".

Theoretically, the audio level should be able to control the SSB power
output, but also in theory, the suppressed carrier would be zero. In
reality, there is a bit of residual carrier, and that is what messes up
doing things "by theory". Controlling the audio alone will work just
fine in a transceiver which controls the output level by adjusting the
drive at some point *beyond* the BFO injection to the balanced
modulator, but the K2 uses the BFO injection to control the power output.

73,
Don W3FPR

Jon Perelstein wrote:

> This may have been answered before, but I couldn't find any search terms that brought up the info I was looking for.
>
> What power and volume settings do people use for PSK-31?
>
> I have a 100w K2 and I use a SignaLink going into the K2's mic jack. The standard approach that has always been recommended to me is to set the rig's power to full power and then control output power with the transmit volume setting on the SignaLink. I set my SignaLink transmit volume so that the RF level on the K2 shows about 30 watts (essentially 3 tick marks) when I'm transmitting.
>
> I've noticed that the K2 gets very hot this way, with the fan going to high high speed.
>
> Is that the right way to run the K2, or should I be doing something differently?
>
> Thanks.
>
>

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Bill Coleman-2

Re: K2: PSK-31 Power Settings

In reply to this post by jperelst

On Apr 28, 2010, at 11:44 AM, Jon Perelstein wrote:

> What power and volume settings do people use for PSK-31?
>
> I have a 100w K2 and I use a SignaLink going into the K2's mic jack. The standard approach that has always been recommended to me is to set the rig's power to full power and then control output power with the transmit volume setting on the SignaLink. I set my SignaLink transmit volume so that the RF level on the K2 shows about 30 watts (essentially 3 tick marks) when I'm transmitting.
>
> I've noticed that the K2 gets very hot this way, with the fan going to high high speed.
>
> Is that the right way to run the K2, or should I be doing something differently?

I would do the same thing that I do for RTTY. Unless you have some supplemental cooling, I would not set the power level to anything over 30 watts for any length of time. If you add a cooling fan to the top of the K2/100 heat sink, you can safely run 50 watts indefinitely. Note that the K2/100 amplifier is progressively less efficient as the power level is dropped.

Also note that the K2 transmit gain varies from band to band, so you'll still have to adjust the volume on the SignaLink. You want to adjust it so you are not driving the ALC -- as high as you can go with little or no ALC indication.

It's actually not hard to hit this point using the RF output meter. Turn up the volume until the output stops increasing, then reduce it slightly.

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

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jperelst

Re: K2: PSK-31 Power Settings

In reply to this post by Don Wilhelm-4

Don,

I'm having trouble with this approach on 40 meters.

I set the power on the K2 to 30 watts and then adjusted
the TX volume on the SignaLink as high as I could without getting any ALC reading.

When I do that, I essentially have zero power output. There's no deflection on the
K2's RF meter and someone who was monitoring my signal said that my signal just dropped off the waterfall. I have a KAT100 and with these settings the SWR light would not light, indicating that there isn't even enough power out for the KAT100 to measure SWR).

When I increased the SignaLink TX volume to get a 30 watt reading on the K2's RF indicator, I was getting 2-4 bars of ALC.

On my FT-897, the power display when I'm transmitting PSK is fairly steady. On the K2 on 40 meters, it was bouncing all over the place, but that may be a function of how the K2 measures RF power out??

I had no trouble using the suggested technique on 20 meters.

Any ideas as to why I'm having problems on 40?

Jon
KB1QBZ

I had no problem using this approach on 20 meters, so I'

--- On Wed, 4/28/10, Don Wilhelm <[hidden email]> wrote:
I would recommend setting the power to 30 watts. Then hold DISPLAY to change the metering to ALC - adjust the audio up just to the point where there is no ALC indication (adjust until you see ALC bars and then back off until there are none). That should give you a cleaner signal and better control of the output level. Since the gain of the K2 transmit chain varies from band to band, you may have to check the audio drive level again when changing to a different band. For further explanation, read on.

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Bob McGraw - K4TAX

Re: K2: PSK-31 Power Settings

Don etc.

May I suggest setting the K-2 to maximum output power, say on CW, and
then adjust the TX level from the Signalink to produce about 30 watts
output. Do not change the power level on the K-2. FYI - This should
work very satisfactorly for any radio.

With a PSK signal there will be some variation in output level depending
on if one is looking at idle data or text data.

73
Bob, K4TAX

> Don,
>
> I'm having trouble with this approach on 40 meters.
>
> I set the power on the K2 to 30 watts and then adjusted
> the TX volume on the SignaLink as high as I could without getting any
> ALC reading.
>
> When I do that, I essentially have zero power output. There's no
> deflection on the
> K2's RF meter and someone who was monitoring my signal said that my
> signal just dropped off the waterfall. I have a KAT100 and with these
> settings the SWR light would not light, indicating that there isn't even
> enough power out for the KAT100 to measure SWR).
>
> When I increased the SignaLink TX volume to get a 30 watt reading on the
> K2's RF indicator, I was getting 2-4 bars of ALC.
>
> On my FT-897, the power display when I'm transmitting PSK is fairly
> steady. On the K2 on 40 meters, it was bouncing all over the place, but
> that may be a function of how the K2 measures RF power out??
>
> I had no trouble using the suggested technique on 20 meters.
>
> Any ideas as to why I'm having problems on 40?
>
> Jon
> KB1QBZ
>
>
>
> I had no problem using this approach on 20 meters, so I'
>
> --- On Wed, 4/28/10, Don Wilhelm <[hidden email]> wrote:
> I would recommend setting the power to 30 watts. Then hold DISPLAY to
> change the metering to ALC - adjust the audio up just to the point where
> there is no ALC indication (adjust until you see ALC bars and then back
> off until there are none). That should give you a cleaner signal and
> better control of the output level. Since the gain of the K2 transmit
> chain varies from band to band, you may have to check the audio drive
> level again when changing to a different band. For further explanation,
> read on.
>
> ______________________________________________________________
> 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: PSK-31 Power Settings

In reply to this post by jperelst

Jon,

That sounds like a classic case of RF where it is not supposed to be -
in other words, first check for RF feedback - lay out a 33 foot piece of
wire connected only to the K2 at the near end, and insulated at the far
end. If the effects decrease, then look to your antenna system for the
cure to your 40 meter problems.

OTOH, there was a problem with the KPA100 developing parasitic
oscillations under certain conditions (like high SWR when using an
auto-tuner like the KAT100), and that parasitic was most prevalent on 40
meters. That problem was addressed by the KPA100UPKIT and is included
on newer KPA100s. If your KPA100 has blue toroids at L15 and L16, then
adding the KPA100UPKIT would be a prudent step. If you have blue
toroids at L16 and RFC1, then your KPA100 is up to date, and my
suspicion about the RF Feedback situation is amplified.

The fact that you can use the procedure for adjusting the output level
on 20 meters says that the method is valid, but you have some sort of
other situation present on 40.

73,
Don W3FPR

Jon Perelstein wrote:

> Don,
>
> I'm having trouble with this approach on 40 meters.
>
> I set the power on the K2 to 30 watts and then adjusted
> the TX volume on the SignaLink as high as I could without getting any ALC reading.
>
> When I do that, I essentially have zero power output. There's no deflection on the
> K2's RF meter and someone who was monitoring my signal said that my signal just dropped off the waterfall. I have a KAT100 and with these settings the SWR light would not light, indicating that there isn't even enough power out for the KAT100 to measure SWR).
>
> When I increased the SignaLink TX volume to get a 30 watt reading on the K2's RF indicator, I was getting 2-4 bars of ALC.
>
> On my FT-897, the power display when I'm transmitting PSK is fairly steady. On the K2 on 40 meters, it was bouncing all over the place, but that may be a function of how the K2 measures RF power out??
>
> I had no trouble using the suggested technique on 20 meters.
>
> Any ideas as to why I'm having problems on 40?
>
> Jon
> KB1QBZ
>
>
>
> I had no problem using this approach on 20 meters, so I'
>
> --- On Wed, 4/28/10, Don Wilhelm <[hidden email]> wrote:
> I would recommend setting the power to 30 watts. Then hold DISPLAY to change the metering to ALC - adjust the audio up just to the point where there is no ALC indication (adjust until you see ALC bars and then back off until there are none). That should give you a cleaner signal and better control of the output level. Since the gain of the K2 transmit chain varies from band to band, you may have to check the audio drive level again when changing to a different band. For further explanation, read on.
>
> ______________________________________________________________
> 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: PSK-31 Power Settings

In reply to this post by Bob McGraw - K4TAX

Bob,

As I stated in my original reply to Jon, that is not the best solution
(in fact it can lead to trouble) for any transceiver that controls the
power output by altering the BFO injection level to the balanced
modulator ( the K2 does that). Transceivers that control the output
*after* the balanced modulator stage will operate nicely as you state,
but the K2 (and K3) control the output level prior to the balanced
modulator, and will have trouble if used that way. Set the power to the
level that is desired and then adjust the audio for no ALC for digital
modes.

73,
Don W3FPR

Robert Mcgraw wrote:

> Don etc.
>
> May I suggest setting the K-2 to maximum output power, say on CW, and
> then adjust the TX level from the Signalink to produce about 30 watts
> output. Do not change the power level on the K-2. FYI - This should
> work very satisfactorly for any radio.
>
> With a PSK signal there will be some variation in output level depending
> on if one is looking at idle data or text data.
>
> 73
> Bob, K4TAX
>
>

Don Wilhelm-4

Re: K2: PSK-31 Power Settings

In reply to this post by jperelst

sometimes it pays to read your own posts or errors.
If your KPA100 has blue toroids at L15 and RFC1, then it is the new
design (and is not the problem source). OTOH, if the toroids are at L15
and L16 and have red cores, the KPA100 should be updated with KPA100UPKIT.

73,
Don W3FPR

Jon,

That sounds like a classic case of RF where it is not supposed to be -
in other words, first check for RF feedback - lay out a 33 foot piece of
wire connected only to the K2 at the near end, and insulated at the far
end. If the effects decrease, then look to your antenna system for the
cure to your 40 meter problems.

OTOH, there was a problem with the KPA100 developing parasitic
oscillations under certain conditions (like high SWR when using an
auto-tuner like the KAT100), and that parasitic was most prevalent on 40
meters. That problem was addressed by the KPA100UPKIT and is included
on newer KPA100s. If your KPA100 has blue toroids at L15 and L16, then
adding the KPA100UPKIT would be a prudent step. If you have blue
toroids at L16 and RFC1, then your KPA100 is up to date, and my
suspicion about the RF Feedback situation is amplified.

The fact that you can use the procedure for adjusting the output level
on 20 meters says that the method is valid, but you have some sort of
other situation present on 40.

73,
Don W3FPR

Jon Perelstein wrote:

> Don,
>
> I'm having trouble with this approach on 40 meters.
>
> I set the power on the K2 to 30 watts and then adjusted
> the TX volume on the SignaLink as high as I could without getting any ALC reading.
>
> When I do that, I essentially have zero power output. There's no deflection on the
> K2's RF meter and someone who was monitoring my signal said that my signal just dropped off the waterfall. I have a KAT100 and with these settings the SWR light would not light, indicating that there isn't even enough power out for the KAT100 to measure SWR).
>
> When I increased the SignaLink TX volume to get a 30 watt reading on the K2's RF indicator, I was getting 2-4 bars of ALC.
>
> On my FT-897, the power display when I'm transmitting PSK is fairly steady. On the K2 on 40 meters, it was bouncing all over the place, but that may be a function of how the K2 measures RF power out??
>
> I had no trouble using the suggested technique on 20 meters.
>
> Any ideas as to why I'm having problems on 40?
>
> Jon
> KB1QBZ
>
>
>
> I had no problem using this approach on 20 meters, so I'
>
> --- On Wed, 4/28/10, Don Wilhelm <[hidden email]> wrote:
> I would recommend setting the power to 30 watts. Then hold DISPLAY to change the metering to ALC - adjust the audio up just to the point where there is no ALC indication (adjust until you see ALC bars and then back off until there are none). That should give you a cleaner signal and better control of the output level. Since the gain of the K2 transmit chain varies from band to band, you may have to check the audio drive level again when changing to a different band. For further explanation, read on.
>

Bob Cunnings NW8L

Re: K2: PSK-31 Power Settings

In reply to this post by Don Wilhelm-4

On Wed, Apr 28, 2010 at 8:14 PM, Don Wilhelm <[hidden email]> wrote:

> but the K2 (and K3) control the output level prior to the balanced
> modulator, and will have trouble if used that way. Set the power to the
> level that is desired and then adjust the audio for no ALC for digital
> modes.
>

Except for the K3 which requires that audio be set for 4-5 bars ALC
for digital modes.

Bob NW8L
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Brett Howard

Re: K2: PSK-31 Power Settings

4-5 bars of ALC is essentially the point where the ALC will begin to
engage and is thus the same thing as what Don is referring to.

~Brett

On Wed, 2010-04-28 at 21:52 -0600, Bob Cunnings wrote:

> On Wed, Apr 28, 2010 at 8:14 PM, Don Wilhelm <[hidden email]> wrote:
>
> > but the K2 (and K3) control the output level prior to the balanced
> > modulator, and will have trouble if used that way. Set the power to the
> > level that is desired and then adjust the audio for no ALC for digital
> > modes.
> >
>
> Except for the K3 which requires that audio be set for 4-5 bars ALC
> for digital modes.
>
> Bob NW8L
> ______________________________________________________________
> Elecraft mailing list
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Don Wilhelm-4

Re: K2: PSK-31 Power Settings

In reply to this post by Bob Cunnings NW8L

Bob,

I thought I explained that the K3 "ALC" meter is like a VU meter for the
first 4 bars - the ALC indication starts at the 5th bar.

73,
Don W3FPR

Bob Cunnings wrote:

> On Wed, Apr 28, 2010 at 8:14 PM, Don Wilhelm <[hidden email]> wrote:
>
>
>> but the K2 (and K3) control the output level prior to the balanced
>> modulator, and will have trouble if used that way. Set the power to the
>> level that is desired and then adjust the audio for no ALC for digital
>> modes.
>>
>>
>
> Except for the K3 which requires that audio be set for 4-5 bars ALC
> for digital modes.
>
> Bob NW8L
> ______________________________________________________________
> 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
>
>

Bob Cunnings NW8L

Re: K2: PSK-31 Power Settings

Sorry, now I see that you did, in an earlier post. The context was
lost (trimmed away) by the time the statement quoted below was made,
so I took it at face value. I only remarked on this because the advice
for any other rig in the world is to set audio for very little or no
ALC indication. The requirement that the K3 be set for 4-5 bars of
"ALC" has been a source of confusion for digital mode setup since the
beginning, as a search of the archives will reveal.

Bob NW8L

On Wed, Apr 28, 2010 at 11:10 PM, Don Wilhelm <[hidden email]> wrote:

> Bob,
>
> I thought I explained that the K3 "ALC" meter is like a VU meter for the
> first 4 bars - the ALC indication starts at the 5th bar.
>
> 73,
> Don W3FPR
>
> Bob Cunnings wrote:
>>
>> On Wed, Apr 28, 2010 at 8:14 PM, Don Wilhelm <[hidden email]> wrote:
>>
>>
>>>
>>> but the K2 (and K3) control the output level prior to the balanced
>>> modulator, and will have trouble if used that way. Set the power to the
>>> level that is desired and then adjust the audio for no ALC for digital
>>> modes.
>>>
>>>
>>
>> Except for the K3 which requires that audio be set for 4-5 bars ALC
>> for digital modes.
>>
>> Bob NW8L
>> ______________________________________________________________
>> 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
>>
>>
>

Jan Erik Holm

Re: K3 ALC meter

>
> On Wed, Apr 28, 2010 at 11:10 PM, Don Wilhelm<[hidden email]> wrote:
>> Bob,
>>
>> I thought I explained that the K3 "ALC" meter is like a VU meter for the
>> first 4 bars - the ALC indication starts at the 5th bar.
>>
>> 73,
>> Don W3FPR
>>

Interesting, good info. Been on this list for 3 years or more
and have never seen this.
Maybe it´s in the manual or maybe it´s been on the list but if
so I´ve missed it.

/ James
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