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ZL1ANM > CW 03.05.07 03:27l 54 Lines 1846 Bytes #999 (0) @ WW
BID : ZL1ANM87
Read: GUEST
Subj: Re: Simple 2 memory keyer?
Path: DB0FHN<DB0FOR<DB0SIF<DB0ROF<DB0ACH<DB0PKE<DB0RES<ON0AR<GB7FCR<ZL2BAU<
ZL1AB
Sent: 070503/0111Z @:ZL1AB.#06.NZL.OC #:59763 [AUCKLAND] FBB7.00i $:ZL1ANM87
From: ZL1ANM@ZL1AB.#06.NZL.OC
To : CW@WW
>Is there any simple way to produce a purely solid state 2 memory cw keyer ?
>
>Ideally I'd wanna build a small pcb and build it into the tin box that covers
>my old Wireless Set 18 Leg strap on key and a small battery.
>
>I certainly don't want mechanical keyers, laptops and other bulky stuff
>when /P.
>
>Would PIC chips be used ?
>
>I don't know PIC's, don't wanna spend dosh just for one project
>or learn a programming language for the same reasons ;-)
>
>Ideas welcome.
>
>- Andy -
>G0FTD @ GB7PZT
Take a look at page 14.8 of the 1992 ARRL Handbook. Described there
is a programmable CW ID'er for repeaters.
For your application, the entire upper half of the circuit diagram can
be ignored, since it consists of a 9-minute beacon interval timer and
an audio tone generator.
The relevant circuitry for your purposes consists of half of a 556
timer configured as an oscillator to provide the system clock for the
4040 binary counter, which addresses the data inputs of the 2716 EPROM.
The data programmed into the 2716 is taken from one of its output pins
(transistor buffering recommended in your application).
This is an 8-bit EPROM, so you could program up to 8 distinct messages
into it. A handful of resistors and capacitors and a couple of cheap
transistors complete the entire unit.
Advantages: cheap, readily available components
expensive crystal not required
5 volt rail, so 9 volt battery & regulator would work
CW speed can be varied at will by adjusting the 50K pot
in the 556 clock section
Disadvantage: messages cannot be changed during operation
The most difficult part will be finding a friend to burn the EPROM
for you.
73 de Neil ZL1ANM
T4 1.5à24
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