K2: active cooling for data modes?

[omehegan]

At the moment I mostly use my K2 (no KPA100) for data modes - PSK31  
and Olivia. I've read that it's recommended you keep the power to 5  
watts for these modes due to the high duty cycle, so I've been doing  
that. But there are times when I hear faraway stations but they don't  
hear me. Maybe it would be futile, but the temptation to turn up the  
power to try and make contact is always there.

Neither antenna improvements nor any sort of amp are in my immediate  
future, but I was thinking today... if cooling the finals is the main  
concern, has anyone tried modding their K2 to include a more beefy  
heatsink and a small fan? Just wondering if the idea even makes any  
sense...

--
[hidden email] (Owen B. Mehegan)
'There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.'
   --William Shakespeare

______________________________________________________________
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

[Julian, G4ILO]

I think the same answer applies as to the earlier thread about running 100W on digital modes using a K3. With PSK31 the IMD products will be too high running the K2/10 at 10W, though to be fair, having done the comparison, my own K2/10 is cleaner at 10W than my K3 is at the same power level and is probably within the bounds of acceptability.

Olivia, MFSK and RTTY should be OK at 10W as they are FSK mode (though Olivia has been all but killed off over here by the selfish hordes running the 2.2kHz wide ROS mode above 14.100.) But the K2/10 was not designed for extended key-down operation. As the heat sink for the 10W PA is the bottom of the case there isn't much scope for doing what you suggest unless you want the K2 to sit on a heat sink. But you should also look at the driver stage which is not heat sinked at all. I found that ran hotter than the PA so I fitted a small heat sink to it internally. I do run my K2 at 10W in digital modes but only for APRS packet where the transmissions a maximum of a few seconds.

Julian, G4ILO

Owen B. Mehegan wrote

At the moment I mostly use my K2 (no KPA100) for data modes - PSK31  
and Olivia. I've read that it's recommended you keep the power to 5  
watts for these modes due to the high duty cycle, so I've been doing  
that. But there are times when I hear faraway stations but they don't  
hear me. Maybe it would be futile, but the temptation to turn up the  
power to try and make contact is always there.

Neither antenna improvements nor any sort of amp are in my immediate  
future, but I was thinking today... if cooling the finals is the main  
concern, has anyone tried modding their K2 to include a more beefy  
heatsink and a small fan? Just wondering if the idea even makes any  
sense...

[omehegan]

Thanks Julian (and those who replied off-list). I guess I'll just stick
with my current practices and save my pennies for a KPA100 (and dream of
moving so I can put up a better antenna)!

Julian wrote:

> Message: 31
> Date: Thu, 3 Feb 2011 01:32:40 -0800 (PST)
> From: "Julian, G4ILO" <[hidden email]>
> Subject: Re: [Elecraft] K2: active cooling for data modes?
> To: [hidden email]
> Message-ID: <[hidden email]>
> Content-Type: text/plain; charset=us-ascii
>
>
> I think the same answer applies as to the earlier thread about running 100W
> on digital modes using a K3. With PSK31 the IMD products will be too high
> running the K2/10 at 10W, though to be fair, having done the comparison, my
> own K2/10 is cleaner at 10W than my K3 is at the same power level and is
> probably within the bounds of acceptability.
>
> Olivia, MFSK and RTTY should be OK at 10W as they are FSK mode (though
> Olivia has been all but killed off over here by the selfish hordes running
> the 2.2kHz wide ROS mode above 14.100.) But the K2/10 was not designed for
> extended key-down operation. As the heat sink for the 10W PA is the bottom
> of the case there isn't much scope for doing what you suggest unless you
> want the K2 to sit on a heat sink. But you should also look at the driver
> stage which is not heat sinked at all. I found that ran hotter than the PA
> so I fitted a small heat sink to it internally. I do run my K2 at 10W in
> digital modes but only for APRS packet where the transmissions a maximum of
> a few seconds.
>
> Julian, G4ILO

--
Owen B. Mehegan ([hidden email])
"He is a dangerous mixture of sophistication and recklessness which
makes one anxious about his influence on other boys."
______________________________________________________________
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