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Drive to Amplifier

"Tuned to 7 watts"? I wonder if the radio still has a clean signal. It must have been tuned to "Ghost Watts" that are up in the 50MHz range.
When I used the radio in 2002 as a base unit, I never received any complaints about spill-over. I recently unpacked it and I am currently using it again as a base unit with a I-MAX 2000 antenna and it is working fine. I did not trust the onboard meter and I now have a MFJ-870 meter which indicates 7 watts on dead key on AM. This is the first time I have seen the RF output power level.
 
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They can be turned up to produce a 7 Watts carrier, I wouldn't expect the radio to be able to reach 100% modulation from there. :)
That's a good point. Because the amplifier is not linear, the radio will need a low dead key because the max peak output is what it is. The radio will need more "swing" to get 100% modulation out of the amp. I did not completely understand this until I got a scope and played around with the dead key adjustment. With the radio dead keying 7w, the amplifier output will be lucky to get 30% modulation because the dead key is taking up the headroom.
 
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That's a good point. Because the amplifier is not linear, the radio will need a low dead key because the max peak output is what it is. The radio will need more "swing" to get 100% modulation out of the amp. I did not completely understand this until I got a scope and played around with the dead key adjustment. With the radio dead keying 7w, the amplifier output will be lucky to get 30% modulation because the dead key is taking up the headroom.

The audio amp in the radio can only do so much without creating excessive THD %, the radio itself will struggle to produce anything near 100% modulation with sinusoidal output at such high carrier power.

Watch the 'scope while sampling only the radio and play with the carrier level.
 

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