[Elecraft] Upper limits of KPA500?

[Edward R Cole]

That seems excessive (shows good engineering).

FM seems to be the hardest mode on amps.  If you are long-winded 
probably exceed 3-minutes which is common Time-out-timer limit on 
commercial FM gear (and several ham rigs, too).  I have a fan switch 
on my 150w 2m amp and too often forget to switch it on when operating 
FM.  My 222 FM 30w radio has built-in TOT which shuts off Tx at 
3-minutes of transmit.

On my QRO sspa's I try not to do any key-down tests over a minute in 
length (and they are designed for JT65 service).  Having overtemp 
protection and SWR protection is good insurance for protecting those 
expensive components.  All my amps have that.

Maybe someday I will own a KPA500 (do very little HF and have a 1000w 6m sspa).

73, Ed - KL7UW

I once blew up a 500w dummy load by excessive transmit time running 
1200w.  Had that old Sierra MW for about 30-years.  Now have a 
surplus 500w Bird dummy.


Date: Mon, 4 May 2020 09:11:56 -0700
From: Jack Brindle <jackbrindle at me.com>
To: Dave Cole <dave at nk7z.net>
Cc: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Upper limits of KPA500?
Message-ID: <8D7F4C18-45F5-408A-B13B-E0BFF47A957C at me.com>
Content-Type: text/plain;       charset=us-ascii

 From the KPA500 manual, Rev E1, page 41 Specifications:
Duty Cycle at 500 Watts 10 minutes key down / 5 minutes standby

Sometimes it is very worth while to read the manual. It gives me 
something to do when being stuck at home for so long gets me down.

73!
Jack, W6FB


73, Ed - KL7UW
   http://www.kl7uw.com
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