Message-ID: <4FC09285.2060102@kpnmail.nl>
Date: Sat, 26 May 2012 10:21:25 +0200
From: pa3abk <pa3abk@kpnmail.nl>
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References: <495778BC-4950-48D3-B5E4-4DBCE69D729C@numeo.fr> <4FC00C2E.6070101@iup.uni-heidelberg.de>
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Subject: Re: LF: 475 kHz exciter
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On 26-5-2012 0:48, Stefan Schäfer wrote:
> I've been thinking about using the 2nd D Flipflop of the 4013 and 
> build a divide by 4 circuit. With this exciter one could easily use a 
> HF TRX like the IC-706 and drive the exciter by transmitting QRP in 
> the 160m band. 1900 kHz will then result in 475 kHz and the frequency 
> accuracy should be fine. In Split-mode one could transmit on 160m and 
> receive directly on MF. Using 3x 150 Ohm / 2W in parallel and another 
> 1 kOhm resistor in series with 2 antiserial Z-diodes should be OK for 
> driving the input of the 4013 and getting a perfect SWR for the TRX... 
> Maybe this is how i will do it.
A similar set-up is running for some time here.
I started with de QTX 100W design with a 2MHz x-tal driven.  (I'm also 
one of those lurkers of this group)
Frustrated by the single channel I realized thet the TS-440 has an "all 
band" option.
Simply replaced the the X-tal with a "dummy"-driven single transitor in 
saturation, which fed de CD4024 by 4 divider.
 From the dummy there is an attentuation by 4. Drive from the TS440 is 
full CCW, almost zero.
It produces100W from 400-600kHz.  Off course only non-lineair modes can 
be used (CW, Opera, Slowhell ect)
There is small interface which plugs into the transverteroutlet which 
drive the  fast reed antenna relais.

Also experimented with a  mixer from 2MHz to 500kHz  which works fine, 
only it requires some caution in relation to the drive.
Otherwise a wide noiseskirt is included. The PA is not lineair and whole 
circuit has a certain "treshold".
NL 600m license is restricted to CW only, we consider Opera when 
prefixed with a morse ID a such, the rest which follows is just test and 
tune signals :-)
The divider route is therefore best suitable in my case.
Jan/pa3abk

-- 
pa3abk<->  dordrecht jo21it