Message-ID: <36EA71BD.A87FA869@sault.com>
Date: Sat, 13 Mar 1999 09:10:06 -0500
From: "Rod Mayward" <rodbarb@sault.com>
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To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Re LF Xtal/mixer Exciters/Synthesizer
References: <3.0.1.16.19990222092454.2f0f994a@mail.cc.kuleuven.ac.be>
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Hi Rik
Did you ever get a chance to scan the schematic and get it on your site for
others to download?  Thanks
Rod
KL7RG/8

Rik Strobbe wrote:

> At 13:01 19/02/99 -0500, you wrote:
> >Hallo Lowfers,
> >
> >Peter, G3LDO mentioned his difficulties to build a reliable and stabile
> >exciter for LF and describes the solution developed by DJ1ZB.
> >
> >I myself also had my difficulties to build a solution from scratch. After
> >experimenting with 5-6 MHz VFOs and frequency dividers, I came accross a
> >nice synthesizer kit. With a frequency range between 1 Hz (!) and 54 MHz
> >(!) it is a real overkill for the LF band, but the features contained in it
> >are excellent for what we are doing. The resolution is 1 Hz, the accuracy,
> >once calibrated is in the same range and long time stability is excellent
> >
> When I started on 136 I just used a simple VFO on 8.6-8.9MHz, divided that
> by 64 and got a nice and stable 136kHz signal. Although it had a +/- 5Hz
> shortterm and a +/- 50Hz longterm drif it was perfect suitable for normal CW.
> When starting with slow CW this drift was not tolerable and I decided to
> built a PLL VFO. I checked out for some special PLL IC's but either they
> were hard to find or far to expensive, so I just took a handfull of
> ordinary CMOS IC's (CD4000 series) a constructed a simple PLL VFO on 8.6MHz
> in 64Hz steps. This signal was divided by 64 to get 136kHz in 1Hz steps.
> Total cost was about 1000BFR (25 Euro), half of it spent on thumbwheel
> switches.
> I ended up with 9 CMOS IC's (OK, you can do it with a single specialized IC
> but these CMOS are available in any electronics shop and alltogether
> cheaper than a PLL IC). Everything fits on a 6 by 9 cm piece of 'testboard'.
> I there is interest I will scan in the schematics and make it available.
> But do not expect something special it is just a 'textbook' PLL system.
>
> 73, Rik  ON7YD
>
> Rik Strobbe  ON7YD
> rik.strobbe@fys.kuleuven.ac.be
> Villadreef 14  B-3128 Baal  BELGIUM   (JO20IX)