[AMRadio] Ranger... good news, bad news
Jack Schmidling
jack at schmidling.com
Sat Nov 4 19:13:02 EST 2006
Gary Blau wrote:
> Read it again.
> The 6146 screen adjust lets you put the RF out anywhere you want from a
> low of ~8 watts to full tilt.
Guess I missed that "detail". Question though... can that change be made
on it's own?
Secondly, I found this contrary statement on another site....
................
Most often mis-modification:
Reducing output power when driving a linear amplifier through the use of
a T connection and a dummy load and/or reducing loading or screen
Voltage. This situation wastes one of this rig's better resources namely
modulator headroom. When altering the R.F. final's impedance through
reduced plate current, the modulation transformer no longer sees the
designed load.
The correct way to reduce output power is to use an external plate
supply with a Variac on the primary or switch the low B+ Voltage to the
final (removing the high B+) through the accessory jack. Either way the
high B+ is left on the modulators. This gives an immediate improvement
to the audio as the modulator requirements are now cut way down without
forcing the modulator into an unknown load. With the accessory low power
mod, the rig will put out abour 12-14 Watts carrier which is a good
level for driving quitea few linear amplifiers. Every available effort
to clean up audio distortion should be considered when runnung QRO AM!
................
Whom do I believe?
js
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