[Elecraft] KPA500/KAT500 and RTTY

[Bob McGraw K4TAX]

While I don't often run RTTY, I do run a good bit of PSK-31, WSJT-X FT-8 
and MSK-144 along with CW and SSB modes.   I do watch the PA temp, 
specially as it nears 65 to 70 degrees C.   I also run with the Fan on 
#1 or #2 for starters.    I know some will say it doesn't make a 
difference while others say it will.   As to me, I know that heat is the 
downfall of solid state electronics.  Cool is always better.

For the above, I normally run 400 to 500 watts, depending which power 
indicator I choose.  And, a very important point,  at any time I never 
exceed 500 watts into a well matched load.   I do have a Bird 43P with a 
500 watt, 2 - 30 MHz, element in-line between the amp output and ATU 
input.   I also have a 500 watt element, 25 - 60 MHz, for 6 meters.

Two facts to which I view one must pay attention:  {per the KPA500 manual}

(a) Duty Cycle a 500 watts = 10 minutes key down / 5 minutes standby

(b) Heat Sink Temp = 90°C Maximum  {194° F}

I view if one exceeds either of these two items above........they just 
became a very underpaid design and test engineer.

73

Bob, K4TAX

Message: 1
Date: Wed, 2 Dec 2020 08:36:54 -0800
From: Dave Cole<dave at nk7z.net>
To:elecraft at mailman.qth.net
Subject: Re: [Elecraft] KPA500/KAT500 and RTTY


Thanks sir...

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources

On 12/2/20 8:24 AM, Gordon LaPoint wrote:

> Dave,
>
> I have done many RTTY contests and regular qso's using the
> KPA500/KAT500/K3 over the last few years. I run full 500 watts with no
> problems, the temp gets up to the 60 to 65 range a lot when calling CQ
> in a contest, or during a 10 minute tx.? If the temp gets to 70 then the
> fan kicks into high gear and is very noisy, but still within specs.
> Gordon - N1MGO
>
> On 12/2/2020 9:57 AM, Dave Cole wrote:
>> Hi,
>>
>> Any recommendations as to the max power I might run using a KPA500 and
>> KAT500, on say, a three to five minute transmission?
>>
>> Also, what is the recommended max temp for the PA on this device as
>> measured by the KPA500?
>>
> _