From: DL4YHF@aol.com
Message-ID: <cf.16a5057.27a07ad0@aol.com>
Date: Wed, 24 Jan 2001 13:37:04 EST
Subject: LF: Re: QRSSS and IC706 stability
To: rsgb_lf_group@blacksheep.org
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Hello Mike and group,

Mike wrote

> Firstly, the frequency stability - presumably of my IC-706 Mk1 - was 
> not good enough for the 30s dot setting. After a long warm-up 
> period, it settled down to a ragged line that wandered all over the 
> screen. My son opened a window in the next room to the shack and 
> the Loran lines moved off the screen completely! Does anyone else 
> have experience of this? I believe a high stability oscillator is 
> available for the 706.

I am also using the old IC706 (at DF0WD) and also got some problems with its 
stability (a matter of some Hertz at 10.137 MHz). The thing gets much worse 
if you use it for transmitting.
I did some test with very slow PSK (and other modes) some weeks ago,
and noticed some dramatic "curves" in the loran lines after switching from TX 
to RX (I use the 706 to drive a transverter).

There is indeed a temperature compensated oscillator availabe, it is a small 
SMD part called "CR-502". It is specified for stability of +- 0.5ppm in the 
temperature range from -30°C to +60°C (so it should be ok). The frequency of 
this oscillator is exactly 30 MHz, so it can be "tied" to any 10MHz reference 
because it has a frequency control input (I already drilled a hole for a BNC 
connector into the housing for that purpose).

Ironically, I am waiting for two weeks for that part now. I will keep you 
informed if I know more about its performance if you like.

73's Wolf.