> In the mid '80's, an outfit called Design Electronics Ohio, out of
> Groveport emerged with a product called the QSK-1500.( Does anyone
> know what happened to these folks?)
It was 1983/1984 ... the QSK-1500 was introduced at the 1984 Dayton
Hamvention. Design Electronics Ohio was Dr. John Sheller, K8RR
(then KN8Z). I was involved in designing most of the control circuits
and (hand) built most of the control boards. John designed the diode
and bias circuits.
The QSK-1500 pre-dated the Ameritron QSK-5 by 6 to 12 months but due
to the cost of the relatively large, "high power" pin-diode and large
RF clokes (the design used several hundred mA of turn-on bias current
to achieve sufficiently low forward resistance at low frequency, it
was expensive for the (cheap) amateur market.
With relatively low sales volume, the demands of John's dental practice,
my business commitments (I started building a group of TV stations later
in 1984) among other issues, DEO "went away" in late 1985/early 1986.
> I think Design Electronics was on the right track when they disappeared.
There were two problems ... availability of high-power, civilian, p/n
diodes and a cost point that most amateurs considered too high ($495).
The QSK-1500 never achieved the mass market acceptance it needed to make
DEO successful.
> If they are no longer in business, or are not interested in producing
> the QSK-3000, perhaps I need to look into doing it myself!
DEO is long gone. I've been away from the Columbus area for six years
now but last I heard John's health was such that I doubt he has any
interest in trying to revive the company.
> Can anyone furnish any knowledge of the company and/or experiences with
> the QSK-1500 or QSK-3000?
Other than one of the original QSK-1500s on my closet shelf and my design
notes (if I can still find them) ... John wrote about the unit in a Ham
Radio article in late 1984, I think. The article isn't complete (no real
construction information) but went into selecting the p/n diodes, bias
calcuations (forward current for "turn on" and reverse voltage for turn
off isolation), and t/r timing issues (I solved the "hot switching"
issue by routing the keyer output through the QSK-1500's control circuit,
keying the amplifier relay and diodes with leading edge of the CW,
adding 2 or 3 mS of delay to both leading/trailing edge of the CW and
passing it along to the transceiver.).
73,
... Joe Subich, W8IK/4 ex-AD8I
<W8IK@IBM.NET>
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