AMERITRON AL-811H Owner's Manual - Page 3

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Also for AMERITRON AL-811H: Instruction Manual (12 pages), Unpacking Instructions Manual (11 pages), Manual (13 pages)

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The red line is the primary damaging high frequency arc path. The path goes through tubes, out through the

filament coupling capacitors. It then travels through the tuned input circuits to the RF input, and that is where your

radio is connected. The arc path is NOT out through the relay control line; a relay line isolation device will not

prevent or reduce arc damage. The arc path is NOT out through ALC; using or not using ALC will have no effect on

radio damage.

(Fig 1)

This kit does the following:

1.)

Adds two "150 volt" Gas Discharge Tubes from filament directly to chassis at the tubes. The

discharge tubes (GDT) surge arrester devices protect personnel and equipment from damaging high

voltage transients induced by lightning, inductive switching, or electrostatic discharge.

transient to about 350 volts absolute peak. Any substitute GDT's should be vetted for performance. GDT's

do not clamp. GDT's ionize at a certain voltage, becoming a near-short once ionized

2.)

Instructs you to directly ground grids in older version that had grid equalizing resistors. This is a critical

update. The grids should always be directly grounded. THIS IS A MUST DO in any grounded grid amplifier

that floats grids from chassis.

3.)

Increases or adds bias. Bias improves tube life and efficiency without noticeably hurting IMD with 3.9 volt

5 watt Zener bias diodes. If your amplifier has a string of bias diodes, you add only ONE of these diodes in

series with the white center tap. If your amplifier does not have a string of bias diodes on the input board,

Littelfuse gas

This limits