[Amps] MFJ Analyzer for adjusting matching network...

[KB0NLY]

After all the discussion on the subject of selecting the proper value of the plate and loading cap i came across a lot of articles in my research on using an MFJ analyzer to do this.  I have access to one so i think i'm going to give that a shot.  I found some pretty good explanations how to do this.

""Adjusting the output pi-network: 

ABSOLUTELY REMOVE ALL TUBE VOLTAGES. Leave the tube in circuit. The plate load impedance of your amplifier is expressed approximately as: [(plate voltage in volts) divided by (1.8 times the plate current in amps)]."" 

For me that would be 2400 plate volts and 600 ma of plate current max, this works out to 2222 ohms. So a 2.2k resistor should be close enough.

""Make up a resistance value close to this number with low inductance resistors, and temporarily place this resistor string from the tube anode connection to ground. This simulates the plate load impedance of the amplifier. The purpose of the pi-network in the amplifier is to change this relatively high plate load impedance value to 50 ohms for your transmission line. Now, hook up a SWR analyzer to the amplifier's RF OUTPUT connector. Adjust the SWR analyzer for a frequency of 50.1 MHz Adjust the copper coil windings (slightly expand or squeeze together) in conjunction with adjusting the output loading capacitor. Adjust for a 1 to 1 SWR reading on the SWR analyzer. When the SWR reading is flat, your adjustment is finished. The top RF deck shielding cover on this amplifier had a small effect on this setting, so a tiny adjustment was necessary when the amplifier was running at full output. It's amazing how close this procedure gets your amp to the final settings. If you don't have a SWR analyzer, consider getting one. Remember to remove the temporary resistor you installed during this procedure. ""

Sounds easy enough, or am i missing something here?

73,

Scott