I haven't tried shorting my antenna,
but I don't recall any reports of uBitx damage due to such a short.
The only issue I see is heat internal to the IRF510.
Each IRF510 is only on 50% of the time, that helps.
I suspect that with a 12v supply, the load presented by T11 and the LPF's and the board traces
would keep the drain current down to where the IRF510 die can transfer ithe heat out to the tab.
And would expect it to take at least 15 seconds for the tab and heatsink to overheat.
Perhaps a shorted antenna never does damage the IRF510's if there is some air flow on the heatsinks.
I could be wrong.
Perhaps others have more information on this.
Jerry, KE7ER
I sincerely doubt it is instantaneous.
toggle quoted message
Show quoted text
On Fri, Jan 1, 2021 at 08:29 AM, Scott McDonald wrote:
Jerry -?
?
This thread has been really helpful.? I haven't failed any 510's in the field yet, but....
?
When you mention a shorted antenna jack and heat-related failure, what kind of key-down times are you thinking about with the standard heatsinks- seconds, a minute, or???
?
I ask because I'm trying to relate it to how long it takes me to realize I have a problem operating portable, which is sometimes longer than I'd want it to be.
?
Thanks, Scott ka9p
?
?
