[Elecraft] KPA1500 Drive Power

[Don Butler]

I have experienced power level changes with s/n 45 since day one.  I had envisioned setting the K3s config to ‘power per band’, adjusting the power level to just below 1500 watts on each band, and then being able to switch bands and magically find that the power level is still sitting exactly where I left it ….. but no deal … typically, after I return to a band where the level had previously been right at 1500 watts, the first couple transmissions (CW) will often jump up to 1600-1700 watts …. It drops a little after the first couple dits, but I almost always have to readjust and crank down the drive power ....  so I now crank down the drive and readjust every time I change bands ….. not what I had hoped for …  and yes,  I also see small decreases in power level as the temperature increases as others have noted.

Don, N5LZ


Sent from Mail for Windows 10

From: K9MA
Sent: Thursday, May 31, 2018 9:42 AM
To: Paul Baldock
Cc: Elecraft Reflector
Subject: Re: [Elecraft] KPA1500 Drive Power

Yes, turning the drive up a bit restores the output to 1500 W.

I haven't recorded it, but drive seems fairly flat band to band. (The K3, of course, saves the drive levels for each band.)

73,
Scott K9MA 

----------

Scott Ellington

 --- via iPad

> On May 31, 2018, at 10:16 AM, Paul Baldock <paul at paulbaldock.com> wrote:
> 
> Can you safely increase the drive to get it back to 1500W?
> 
> Another question: Is the drive requirement (amp gain) pretty flat from band to band?
> 
> - Paul  KW7Y
> 
> At 08:10 AM 5/31/2018, Bill Stravinsky via Elecraft wrote:
>> Yup, as the temp climbs the output drops some.  Even though I'm glad I got the solid state amp I still prefer tubes, hi.  The drop is anywhere between 100 to maybe 300 watts.I never really noted the exact numbers. BillK3WJV p.s. I'm thinking its a normal solid state thing.     On Wednesday, May 30, 2018, 4:23:47 PM EDT, K9MA <k9ma at sdellington.us> wrote:  I'm using the K3 with the Elecraft interface cable.  I've noticed the the CW drive power required by mine varies considerably, both with temperature and SWR.  If I set the K3 output for a KPA1500 output of 1500 W output initially, the output will drop to perhaps 1100 W when the temperature stabilizes at around 65 C.  (I've ruled out any change in antenna impedance, etc.)  A similar change occurs if the SWR goes from 1:1 to 1.2:1 when changing frequency or switching antennas.  I haven't changed the ALC from the default setting.  Has anyone else noticed this? 73, Scott K9MA -- Scott  K9MA k9ma at sdellington.us ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft   Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft at mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to k3wjv at yahoo.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft   Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft at mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to paul at paulbaldock.com
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