K2/100 and ACOM-1000

[ON4FG]

Hi,

I just got an ACOM-1000 that i am using with my K2.
When I am drivng it with 13...14W for approximately 300W output, I noticed
that I got a power output reading in excess of 1kW during the start of my
SSB transmission, just for a second or less. CW seems to be ok.
Does anyone else noticed this? What can be done about it?
I heard that some FT1000 had a transient, putting 200W into the amplifier at
the start of the transmission, and the PA did not survive this.
I do not want this to happen with my PA.

73
Stefaan ON4FG / OP4T / TZ4T

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[Julian, G4ILO]

I think that in the K2, the ALC is implemented by firmware. It takes a
couple of seconds to adjust to the correct level, the first time after
the radio is switched on. Perhaps that's what you are seeing?

Perhaps you could try reducing the mic gain, or get in the habit of
"whistling up" the audio with the amp switched out, the first time you
power on, to let the ALC set the correct level?

--
Julian, G4ILO K2 s/n: 392  K3 s/n: ???
G4ILO's Shack: www.g4ilo.com
Zerobeat Ham Forums: www.zerobeat.net/smf


On 11/2/07, ON4FG <[hidden email]> wrote:

> Hi,
>
> I just got an ACOM-1000 that i am using with my K2.
> When I am drivng it with 13...14W for approximately 300W output, I noticed
> that I got a power output reading in excess of 1kW during the start of my
> SSB transmission, just for a second or less. CW seems to be ok.
> Does anyone else noticed this? What can be done about it?
> I heard that some FT1000 had a transient, putting 200W into the amplifier at
> the start of the transmission, and the PA did not survive this.
> I do not want this to happen with my PA.
>
> 73
> Stefaan ON4FG / OP4T / TZ4T
>
> _______________________________________________
> 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
>

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[David Powell-10]

Stefan

I too have a K2 and Acom 1000 and have experienced the same problem. As I usually use the K2 for CW at just 100W I have done nothing to tackle the problem - I just use the Acom with my TS2000 on those rare occasions I want to run SSB.

This is a known problem - take a look at this (and the subsequent messages in the thread):

http://marc.info/?l=elecraft&m=113376989224579

Hope that helps....

73

David
G3XLW


ON4FG <[hidden email]> wrote :

> Hi,
>
> I just got an ACOM-1000 that i am using with my K2.
> When I am drivng it with 13...14W for approximately 300W output, I noticed
> that I got a power output reading in excess of 1kW during the start of my
> SSB transmission, just for a second or less. CW seems to be ok.
> Does anyone else noticed this? What can be done about it?
> I heard that some FT1000 had a transient, putting 200W into the amplifier at
>
> the start of the transmission, and the PA did not survive this.
> I do not want this to happen with my PA.
>
> 73
> Stefaan ON4FG / OP4T / TZ4T
>
> _______________________________________________
> 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

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[Mike Harris-9]

Hi Stefaan,

Same here.  It is a problem with overshoot of the requested output on SSB.
CW is perfectly OK.  Not much you can do about it.  I've tried the mod to
make the AGC more aggressive on the SSB board without much real effect.
The problem is worse on 40M and progressively decreases as you go up in
frequency and the overall TX gain drops.

The only solution I have is to turn the drive power way down on the very
odd occasion I use SSB on 40M, mainly because I don't like to see the amp
being thrashed.

I guess the overall problem is that the K2 was never really designed to
cope with +25dB gain on top of the base QRP setup.  We are just pushing
the thing too far.

Having said that, there must be a raft of items on the K2 wish list that
could be addressed when the K3 frenzy dies down.  A revised SSB board
possibly and some firmware upgrades.

Regards,

Mike VP8NO

| I just got an ACOM-1000 that i am using with my K2.
| When I am drivng it with 13...14W for approximately 300W output, I
noticed
| that I got a power output reading in excess of 1kW during the start of
my
| SSB transmission, just for a second or less. CW seems to be ok.
| Does anyone else noticed this? What can be done about it?
| I heard that some FT1000 had a transient, putting 200W into the
amplifier at
| the start of the transmission, and the PA did not survive this.
| I do not want this to happen with my PA.
|
| 73
| Stefaan ON4FG / OP4T / TZ4T

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