Until I started experimenting with QSK timing, I never used a scope. Now, I
leave it on-line all the time and I would never do without it. It's
interesting to not only hear, but see the effects of an amplifier's
electronic bias circuit on a keyed waveform. I should have mentioned that I
also use an accelerated "speed-up" circuit on all my amplifier's vacuum
relays. Between the speed-up circuit and the auxiliary open-collector, I've
never seen hot-switching on my scope. A good acceleration circuit coupled
with a Kilovac HC-1 is tough to beat.
Incidentally, Kenwood makes a great, "near lab quality" scope in their CS
series. I have a CS-4125 which I believe sells for around $380 from Print
Products International ( www.prodintl.com ). It's accuracy and resolution
is far better than the ham-oriented monitor scopes.
-Paul, W9AC
-----Original Message-----
From: measures <2@vc.net>
To: Paul Christensen <paulc@mediaone.net>; AMPS <amps@contesting.com>
To: <amps@contesting.com>
Date: Thursday, May 18, 2000 2:29 PM
Subject: Re: [AMPS] QSK5 Unit
>
>>I think the speed you need depends on whether you can get a good early
>>'transmit' signal from your exciter
>
>As an alternative, I presently use a CMOS II keyer with an "auxiliary"
>open-collector transistor to ensure that the amp is keyed fractionally
ahead
>of the transceiver. The primary keyer output connects to the transceiver
>key jack in a bussed arrangement to all my transceivers. Then, the
>auxiliary open collector is run in parallel with the transceiver's external
>amp relay or open-collector. In effect, I have a key bus of open-collector
>outputs that run into all my amps. With the bussing technique, I do not
>need to worry about switching or directing the control of my amps; it's all
>automatic and transparent to me and hot-switching is avoided at all keying
>speeds. The keyer's auxiliary output ensures that the amp "makes" fast
>enough, then the transceiver's own amp key line ensures that the "break" is
>adequately long to avoid hot-switching on waveform's trailing edge.
>
? A break delay necessarily subtracts from the next make. QSK has way
more gotchas than it looks. An o'scope is indispensable.
cheers, Paul
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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