[AMPS] Amp keying (was Bias for SB-220)

[Pete Smith]

At 12:14 PM 6/2/1999 -0400, Dick Green wrote:
...
>
>Unfortunately, the combined rig and amp delays shorten the length of each CW
>element. This is not a problem for speeds up to about 20-25 WPM, but may be
>unacceptable at higher speeds. The effect is a very choppy sounding signal.
>One solution is to use a keyer that allows the weighting to be adjusted to
>counter the effect. The transmitted signal sounds good, but the sidetone
>signal may be annoying if you don't like weighting. If the amp uses a delay
>circuit, it may be possible to adjust component values to shorten the
>combined delay to the absolute minimum required by the relays. I suspect
>that good sounding high-speed QSK CW can be achieved with a delay of
>10-15ms, which should be enough to switch a vacuum relay.

More than enough.  Scott, K9MA, has designed a vacuum relay QSK system that
takes advantage of the fact that the TS-930 turns on a +12VDC line 2ms
before RF output.  With appropriate current-limited power to speed up the
vacuum relay, that's plenty of time to make contact before the RF arrives.
He's been using it with a modified SB-220 for years.

73,  Pete N4ZR
Sometimes a tower is just a tower

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