Warren,
That proves first get the signal to the mixer clean and at a reasonable level.? IT also finds the needed level to the mixer?
and that is under -10dbm for the available LO drive (that can increase maybe 2-3db).
The power amp I've been writing about since May has issues, many, and you have cataloged them.
Those being poor gain flatness, 3 vs 30 mhz.? it currently sags about 11db.
Poor IMD, many reasons including stages going into gain compression and that point varies with frequency due to poor devices.
Also the 3904 has a gain vs current that is a decreasing value with increasing current so the device becomes increasingly non linear.
The IRF510 is operating with a Drain to Drain load of 50 ohms. the calculated non saturating power out is 2.88w at 12V.
This is consistent with your 3W (at 13V?).? ?Either way the Drain load is way too high.? The transformer T11 is both
undersized for ferrite volume and the turns ratio is 1:1 and we need more like 1:2 or greater.? That means a drain load of
must be lower, at least half more like 1/4.?
And so it goes for the entire power chain.
