[Elecraft] KPA500/KAT500 and RTTY

[DC]

I run 500 watts FT8 6 through 80 meters with a maximum SWR of 1.2 to 1 into an 80 meter full wave loop and a 6 meter beam.  Even on the hottest of days I have never seen 70 degrees on the KPA500 utility.  BTW, I use it 95% remote and it works great. 

If I ever saw over 70 degrees I would let it cool down and look for a problem.   The utility is great for remote operation with a program like team viewer or Google Remote.

Richard
K6VV


Sent from my iPhone

> On Dec 2, 2020, at 3:02 PM, Dave Cole <dave at nk7z.net> wrote:
> 
> 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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