[Elecraft] KPA500/KAT500 and RTTY

[Dave Cole]

Thank you Bob, getting some actual numbers helps...  I cut off 
operations at 70C.  In fact, if it starts getting above 65, I will 
terminate ASAP.  Knowing it could get to 90C makes me feel a lot better!

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 1:25 PM, Bob McGraw K4TAX wrote:
> 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?
>>>
>> _
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