Hello to all .
I joined to pose a questionand also to copy mail to see what is new.
I have a solid state push pull Broadbanded RF amp that I have replaced
the transistors but the unit is taking off at higher power levels. I
placed a LPF on the input drive to the amp as I would see the 3 harmonic
at 6 dB below the carrier! THe filter cured that. Looking at the
signal from an HP analyzer , I see multiple harmonics spaced about every
2 Mhz below the carrier frequency into a 50 Ohm load. On lower power
levels, the closest is 20 dB down , but at higher only 10dB On an
antenna , It takes off and pulls horrendus currents and drags the supply
voltage down to 9 or 10 volts if I plase it on an antenna with a tuner.
?...Is it normally required to neutralize this amp when replacing the
finals?
?...What techniques are used to do this?
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Ron
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