Maximum safe SWR?

Steve Gaarder

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Feb 6, 2021, 5:05:56 PM2/6/21

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I hear that too high an SWR can fry the finals. How large an SWR is safe for the HL2 at full power? Is it different at, say, one watt?

thanks,

Steve Gaarder

KD2USS

Steve Haynal

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Feb 7, 2021, 1:50:56 AM2/7/21

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Hi Steve,

The finals on the HL2 are pretty rugged. I have never done a test to purposely see at what power and SWR they might fail. I and others have accidentally transmitted at 5W with no antenna or an antenna tuned for another band without any harm. I suspect the HL2 will heat up enough and turn of the TX power automatically before damage is done. PA final damage is uncommon and I'm trying to remember the last time (if any) I saw damage due to high SWR. I do remember a couple of incidents where the finals were damaged due to poor installation of the heat shim.

73,

Steve

kf7o

radi...@mail.com

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Feb 7, 2021, 5:15:37 PM2/7/21

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Ashamed to say I have abused the PA horribly (just with sloppy impatience to get on air - not proud of it!) and transmitted several times into unmatched random wires with high SWR. No damage done. It's rugged!

73

Max

James Ahlstrom

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Feb 9, 2021, 11:55:40 AM2/9/21

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Hello Group,

Max, how could you! I never did anything like that.....

Oh wait. Yes I did. More than once, too. And into an open circuit. No damage. So the finals are very rugged.