[AMPS] 2 tone intermod test

[Steve Thompson]

>>The TS830 seems good
>>(until the driver fades) while my FT990 is horrible. As
soon
>>as the ALC comes into play, there is a leading edge spike
of
>>typically double the set power for a few ms before the
level
>>settles to nominal.
>
>- which indicates that the mic. gain is set too high.  On a
solid state
>radio, ALC indicates that overshoot is taking place.  Less
ALC is better
>than more ALC.  I run my ts440 where the ALC barely
flickers.  I know
>that a midrange ALC indication means more feculence.  If
folks monitored
>peak RF output voltage with an oscilloscope they would be
better off.
>When using an amplifier that does not use a regulated anode
supply, more
>mic. gain always means less PEP.


In general I agree, but on some rigs mic gain doesn't seem
to matter as much and I don't think it's the whole story
with the 990. I've now got the circuits so when I've
finished fooling with it, I'll make the findings available.
>
>>You certainly know all about it for +/-
>>20kHz when listening on a monitor rx while talking.
>
>The only thing that matters is:  how far down is the
splatter?.

For the use in question (a moderately large vhf contest
station) far enough down is when local stations can't hear
it. With the 830, the splatter on the local R4C disappears
at about 8-10kHz and stations 15 miles away can work within
15kHz of us. We went to use the 990 last time out and
threw it out before the contest after listening to it at the
IF drive frequency, so I don't have a comparison.

Steve



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