>From Dave, N1EA came the following great advice:
"You use the computer to drive a keyer (the MM-3?)
- and this keyer drives several relays - each of which is the
same type of relay and keys each separate transmitter.
The chief reason for using relays - is that you completely ISOLATE
the different transmitters from each other - they are controlled
electromagnetically by relays - and there is NO direct connection.
RS sells a small relay that looks like a yeast cake - but flatter.
About 3/4 inch square and 1/4 inch high - it has little pins to fit
into a pc board - it is very fast. (Anyone out there know this unit's
RS cat. number?).
They also had a "reed" type relay that used to look like one of those
glass vials that were covered by knit cloth that they administered to
people who had fainted in church. Anyway perhaps a poor description
but they are cylindrical about 3/8 inch in diameter and about 1-1/4
inch long. I believe they had three or four pins to mount on a pc
board.
You can do "ugly" construction - which is excellent. Use crazy glue
to glue the parts to the pc board. Then use the "legs in the air" to
do point to point wiring. It works excellently - in fact when people
make receivers using this method of constructions they get lower
noise and better rejection - less problems with instability -
especially on V and U HF.
The trick is to find a fast switching relay that won't die.
Then put them in parallel to key the transmitters. Use the same
relay in each key line - so that the keying characteristics - you
probably will have to change the weighting of the program to send
good CW on the air.
Also among the files in the MILL program you will see files (JPG) and
GIF files which show how to make a simple relay driver to key a
transmitter - you will just use this to key several relays -
(I have not yet found these illustrations, but am poking
about, hi).
Now that is great info from one of the reflector's patriarchs!
Thank you, Dave!
73, Jim KH7M
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