Message-ID: <4DD55989.1050002@iup.uni-heidelberg.de>
Date: Thu, 19 May 2011 19:55:21 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: RE: FCW keyer...
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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: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.org] namens Szigy [yo2is@9a0tcp.ampr.org]
> Verzonden: donderdag 19 mei 2011 9:39
> Aan: rsgb_lf_group@blacksheep.org
> 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
>