> Is this phenomena peculiar only to Icom rigs, or do Yaesu and Kenwood do
> it also?
>
> Funny, these rigs - slow attack on ALC, too fast a rise on the rising edge
> of the keying waveform...........somebody has reversed priorities!
> 73
> Peter G3RZP
Well Peter, I sure notice it on FT-1000MP's. I had a loaner FT-
1000MP here, and it spiked on leading edge....although nothing
like some rigs.
My FT-1000D, ICOM 751A's, and an IC-781 do NOT spike. Some
Kenwoods are phenomenal in spiking. My T4XC's all spike to 200
watts before dropping to the lock-down output of 120 watts!
Using a 775DSP here, I had constant tuner arcing troubles
because my PA would follow the overshoot. The PA would output a
pulse of 7 kW before settling back to 1500 watts or so! If I
underloaded the PA by tuning it only for 1500 watts, I'd get
constant overload faults on the grid and occasional tank circuit
arcs.
There are also many rigs with excessive CW bandwidth from poor
keying shape, the FT-1000MP is about at the top of the heap. I'm
thinking of buying one for self-defense, to keep other MP's away
from me two or three kHz.
I have receivers with solid-state diode mixers driving tandem 8 pole
filters. The first filter is 600 Hz, the second 250 or 500 Hz. One dB
blocking DR is 140 dB on those receivers, and I still can't get within
2 kHz or more of many rigs without hearing severe clicks. That's
true even when signals are 50 dB or more below the blocking point.
I'm amazed so few people complain about the clicks, I guess they
are either used to it or think it is not correctable. Someone needs
to get the manufacturers to pay attention to what they are doing,
because these problems not only aggravate other operators they
also beat the hell out of amplifiers and other components that
follow the rigs.
73, Tom W8JI
w8ji@contesting.com
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