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suggested keyer weight for amp tuning
Hello, I have a little used MFJ-492 electronic keyer that I've decided to
put to good use as an amplifier tuner. (This is my first amp). The keyer defaults to a 50% duty cycle and I would like to get this down to around 10 or 20 percent. Any suggestions on what weight to use? This keyer is adjustable from 5 to 95 percent weight...I do not have a scope so would have to guess by ear. Thanks for the help. Craig KB8FGC |
suggested keyer weight for amp tuning
Hi, Craig
Sounds like 50% keyer "weight" would be the same as 50% duty factor. If you have an analog Ohmmeter, you can use that to check the weight. Assuming the red lead of the Ohmmeter puts out + volts, connect it to the + keying output ("direct" output of the MFJ-492), with the black Ohmmeter lead to ground. With Ohmmeter set to RX100, set keyer to "tune" and adjust Ohmmeter to zero Ohms. Key the keyer at high speed, 50% weighting, the Ohmmeter pointer should be at half-scale of the Ohmmeter with a string of dits. 20% weighting should be 20% of full scale. If your analog Ohmmeter scale shows 20 Ohms at half scale, it may indicate about 100 Ohms at the 20% of full scale point. If you don't have a scope to use the pulse tuning method, do you have a peak-reading rf Wattmeter? 73, Ed Knobloch Craig wrote: Hello, I have a little used MFJ-492 electronic keyer that I've decided to put to good use as an amplifier tuner. (This is my first amp). The keyer defaults to a 50% duty cycle and I would like to get this down to around 10 or 20 percent. Any suggestions on what weight to use? This keyer is adjustable from 5 to 95 percent weight...I do not have a scope so would have to guess by ear. Thanks for the help. Craig KB8FGC |
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