Content-Transfer-Encoding: 8bit
Message-ID: <5.1.0.14.0.20020814112140.00b41ad8@pb623250.kuleuven.be>
Date: Wed, 14 Aug 2002 11:32:04 +0200
To: rsgb_lf_group@blacksheep.org
From: "Rik Strobbe" <rik.strobbe@fys.kuleuven.ac.be>
Subject: Re: LF: Oscillator Stabilty for QRSS?
In-reply-to: <DSkaxPADChW9Mw8f@telemetry.demon.co.uk>
References: <000a01c242fb$2b68ace0$7211f4cc@jsm>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Sender: <majordom@post.thorcom.com>

Hello Tom and Steve,

Some years ago I built a 3.5MHz QRP TX using a 3.58MHz ceramic resonator. 
After some experimenting with the caps (to compensate the temperature drift 
of the ceramic resonator and the FET) I obtained a drift of less than 
10Hz/hour. Divided down to 136kHz this would be a drift of 0.4Hz/hour, good 
enough for QRSS at 3 or 10 sec/dot but maybe a bit on the edge for the TA 
stuff at 1 min/dot or slower.
The frequency range was 75kHz at 3.5MHz, so that would be about 2.8kHz at 
136kHz.

73, Rik  ON7YD

At 09:10 14/08/2002 +0100, you wrote:
>Steve
>
>Buy one of the ceramic (as opposed to quartz) resonators in the 2.5 MHz
>region and use in a VXO circuit. About 100pF variable gives me band
>coverage. Divide by 18 for 136 output, any drift is also divided by 18.
>It's nice and stable for normal CW operation but I have never actually
>measured its stablilty so have no idea if good enough for QRSS.
>
>73, Tom G3OLB
>
>In message <000a01c242fb$2b68ace0$7211f4cc@jsm>, Steve McDonald
><jsm@gulfislands.com> writes
> >Perhaps someone who has already 'been there' can offer their advice.
> >I would like to start building the exciter stages for what will be my 
> 136KHz tx