Re: SK3 and touch paddles (long!)


From: Robert J. Gobrick (
Date: Fri Jan 05 1996 - 23:05:12 EST

Hi Rich,

Good work on your archive retrieval.

Some quick notes on the touch paddles (I know you didn't want to do this
commercially), but Ramsey has two items you may be interested in. One that
they offered in their new catalog (by the way Ramsey Electronics has really
gone upscale with their catalog and they look like they are really going
upscale with some of their new kits) is a simple Touch Switch Kit (which
uses the CMOS circuit you talk of) for $6.95 US.

Also I was able to buy from them, as a spare part, the two paddles they use
on their fancy touch paddle keyer CW-700 Micro Memory Keyer. I think they
sold me the touch paddles for $4 US. Their touch paddles differ from the
ones in my "Copperhead" keyer which, as you mentioned, needed the side of
your hand (which rested on a copper pad) as well as your fingers to complete
the dits and dahs. Their paddles are a "etched" pc board of spiral hot and
ground lands which only need the resistance of your fingers to "gap" the
circuit. I am sorry to say that I still have not got around to finishing
building my "ultimate" low cost backpacking keyer using these parts. I have
found no better portable paddles that would put up with a little abuse in my
backpack - I just can't force myself to buy one of those beautiful German
made Shurer mini iambic paddles and just "toss" it in my rucksack.

Anyway good luck and keep us informed on your progress for your "travel" rig
for your next trip to Poland or wherever you head off to (Albania??)

73/72 Bob VO1DRB/WA6ERB

>Some more questions
>I once built touch paddles with a few cheap CMOS chips. The working
>principle was the conductivity of the skin, and that has inherit
>problems. One is that to measure conductivity, you need two points of
>contact. So it wasn't enough to touch the plates with thumb or finger,
>in addition to that the hand had to rest on a base plate. Moreover, if
>my hands were extremely dry, it worked erratically. Luckily normally the
>excitement of a CW conversation keeps my palms quite moist! ;)

>VO1DRB/WA6ERB, from 16 Nov 1994:
>> I am still working on a project of mounting the Curtis keyer in a little
>> case and mounting a pair of $4 Ramsey capacitance-touch paddles and
>> circuitry in the same case - that would make it small, light and cheap.
>> I have used touch paddles before (have a paddle called the Copperhead
>> that was in May 1991 73 magazine and it really does work half way
>> decent.
>I think the Copperhead design works on the resistive principle, but how
>about the Ramsey paddles? Do they work well? - I am not really looking
>for a commercial kit, but rather for a good, small, reliable design that
>I could reproduce myself. Low power consumption is essential.
>Richard Hieber, DL8MFQ/AA8CP
| Bob Gobrick - VO1DRB/WA6ERB/VE2DRB - Newfoundland, Canada |
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