No subject

W8JITom at W8JITom at
Thu Feb 29 12:37:26 EST 1996

age dated 96-02-28 19:35:38 EST, you write:

>	mebbe im out to lunch but i key my ten-tec titan directly
>	wid the probs so bravo

There is a "spike" that decays over several RF cycles. It changes from band
to band and with supply voltage. That indicates it is from ALC response time.

But the 706 is no worse than the Kenwoods I've seen. I had a new Kenwood (the
DSP one) here the other day, and no matter what power the rig was set at it
produced a 140 watt "spike" when keyed!

The IC-706 produced a maximum "spike" of 130 watts when first keyed when the
supply voltage was 16 volts. When the supply voltage was reduced the "spike"
(actually several decaying RF cycles) was reduced also.

The power could be set at any level and the "spike" (actually envelope
overshoot) isn't reduced. The worst case overshoot will always be with high
supply voltages and low rig output powers. For example, if the rig is set at
60 watts and the supply is 15 volts, the overshoot will be 120 watts or so
before settling down to 60 watts. This can be cured by applying a fixed
external ALC bias to the rig so the ALC voltage is not at zero when the
envelope starts to rise. If the envelope rises faster than the ALC responds,
the carrier will overshoot. External fixed ALC bias should cure that.

I doubt that that spike would hurt anything except a solid state PA. I think
the ETO is a bit overprotected!

73 Tom 

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