My TS790 gives more power as the input of my amplifier can handle. So I needed a power meter to see how much power I transmit in SSB not to overdrive my amplifier. So the FET (BLF248) won`t die in a short time. 15Watts in FM is seen clearly on a regulat wattmeter,..but PEP is another story, my meter will only show around 10watts. |
Again I can go ands write a lot,..but we all know how it works and there are several designs on the net available, complete with schematic and circuit board designs. Here a complete description in PDF made by DD7YB. Watch out for R5 on the board,..it is placed wrong so take care not to copy the board as it is. |
I modified the schematic so I also can measure SWR. It`s more comfortable to have a more complete meter to measure things, here below the schematic as I modified it. For the directional coupler I used the
very same design as for my 2mtr linear amplifier (BLF248). But for the
higher frequencies the coupling is made closer to transmission line. |
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augustus 2010