Hello Szigy, LF,
Sorry for my delaied answer. I will further answer in a personal mail.
About DFCW: Yes, the first you may use is Rik's QRS program (which i am
using too at the moment). With the two 12 V (up to about 10 mA) levels
from the RS232 you can directly steer a NPN transistor or a FET or an
optocoupler to push the PTT. The other one is needed for DFCW.
Realising the small frequency shift can be done in several ways of
course. It depends on your type of VFO. You told me to have a XTAL VFO.
So what you can do is just to pull the XTAL a bit. In my first DFCW
generator i did it with a simple NPN transistor (BC548C, just cause it
was available) that switches a small C against ground. C is some pF,
adjustable to set a proper shift. You can use varicap diodes
alternatively but actually it doesn't matter.
73, Stefan/DK7FC
Am 19.05.2011 09:50, schrieb Rik Strobbe:
Szigy,
I can offer you a software solution:
http://www.qsl.net/on7yd/zip/qrs408.zip
73, Rik ON7YD - OR7T
________________________________________
Van: [email protected] [[email protected]]
namens Szigy [[email protected]]
Verzonden: donderdag 19 mei 2011 9:39
Aan: [email protected]
Onderwerp: LF: FCW keyer...
rom: YO2IS
Some days ago had a nice random QSO with DK7FC on 137.7 KHz.
We started in QRSS then he come back with a loong DFCW message.
Unfortunately had no DFCW keyer capability.
Have built several PIC (16F84) keyers including the SM6LKM beacon
keyer modified by me for QRSS, but none has the DFCW option.
Being a H.M. fan am looking for some afordable ideas.
73& DX !, Szigy
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