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Here is one of many posts from Allison that are worth reviewing, mentions the 6m 225W power amp she built using 4+4 IRF510's in push-pull. The whole thread is worth a read.

and here is where bias and standby current (class A A/B C) comes into play :-) dg9bfc sigi Am 03.08.2022 um 15:07 schrieb Max via groups.io:

"I also use the quad shield with good results up to about the 800watt level" WOW I consider 20 watts to be high power lol -- '72 Aaron K5ATG

Alan, I like the idea of the solar system but I am also rebuilding my 12-inch Dobsonian telescope with a lot of space imagery and I think my XYL may object to more space stuff in the house. Although I

I also use the quad shield with good results up to about the 800watt level... if everything is right (no sharp bends anywhere) it works just fine. Otherwise I have melted and spectacular flash arc

Got it.? I thought it might be something like that.? I have a QRPGuys Tuning Indicator that that I was using with my uBitx v6 transceiver.? It looks like the same circuit.? I'll replace the single

Jack, How much voltage were you running on the drains? - f [email protected]> wrote:

We've tested the T41 with its 510s to 40W and nothing fried. 80-40-20M all can deliver about 25W without much effort. 15M is about 20W and 10M drops to about 13W. Like I said, it is what it is...

The IRF510 can work dependably, Allison reports years of success with HF amps at 40W push-pull, surviving everything from accidental open antenna connections to dead shorts. In posts to this forum

Press on the cq decode and then, F1 for "reply to cq"

Interesting discussion. Just a few very quick thoughts I think that you have to consider the average of the input power to consider the input impedance of the power device as the instantaneous power

Farhan, The answer to that question would depend on instructions or guidelines that would minimize the occurrence of the failures.? If there is no way to use a tuner without a high risk of finals

The builtin FT8 reception works great.? I'm hearing stations from around the world. However, I'm having trouble transmitting.? Software has been updated to the latest available today.? I've entered

The RD16HHF1s are no longer in production. There are some really good parts from Nexperia. They have no easy names like 807 or 6146. They have names like AFT05MP70. Why have short names when you can

We went through that same questioning process. Someone dinged us a few days ago because we're using the IRF510's. Out answer may be different because we are aiming the T41 at experimenters who may

I guess the best way out is to use a robust transistor pair like the RD16HHF1 which can withstand infinite SWR, match the antenna regardless of the impedance at either end with an inline swr meter.

There's an excellent wikipedia article about this transmitter:??https://en.wikipedia.org/wiki/Grimeton_Radio_Station "The Grimeton transmitter is the last surviving example of an Alexanderson

Not sure which statement that would be. I've been making lots of them. A resistive SWR meter assumes that the transmitter wants to see a 50 ohm resistive load, but the transmitter will not necessarily

Yes, the transformer at T8 matches the extremely low impedance coming out of the IRFZ24N's to something near 50 ohms.? There is also a discussion here about an external antenna matcher to match that

My first guess for having different values of SWR reported at different power levels would be that the SWR measurement device cannot accurately measure the two power levels.? This does make sense to