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If you don't have a low pass filter for 160 meters between the rig and your dummy load, then the scope will be showing any second harmonic coming out of the final. That could be why it looks "weird", and you would not be legal to transmit without an appropriate filter. The rig only has filters suitable for use down to 80 meters. Yes, 3v peak is kind of anemic, could be anything between the mike and the IRF510's. Or the 10x switch on your scope probe, that would fully explain this. I'd recommend you concentrate on 80m, where your scope should work well. While transmitting CW, what is the RF pk-pk signal voltage you see at Q90,911,92,94 base or gate? Check current into PA-PWR while transmitting SSB with no audio at the mike, should be around 200ma. If anywhere near, leave the IRF510 bias adjustments at RV2,RV3 as they are. There is considerable variance on output power for these rigs, would be interesting to someday figure out why.? Increasing power is best done by increasing drive at RV1 or adjusting the gain of the mike amp at Q6. But be sure your transmitted signal remains clean, overdriving the final will make it non-linear. Though yours is more than an order of magnitude lower than it should be, so something else is wrong here. Jerry, KE7ER On Sun, Mar 4, 2018 at 07:47 am, John wrote: Well end of this week my TDA2822L and the sockets arrived so I could continue with my search. |
