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From: "Dave G3WCB" <ganymede444@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
Date: Thu, 2 Apr 2009 20:21:37 +0100
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Subject: LF: QRSS / beacon test on 503.7kHz [resonators]
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Rik, LF,
I use a Murata 1 Mhz resonator, divided by two for a 500 kHz
direct-conversion RX. It drifts about 10 Hz per hour, about the same as your
4 Mhz unit. It tunes the whole 500 kHz band with a 150 pF series capacitor,
and is fine for CW and other casual listening.

For transmitting, I use a 5040 kHz crystal divided by ten. This is a very
common reference clock crystal, and I found that if I unsoldered the top of
the can and scribbled on the quartz plate with a soft graphite pencil, it
tuned down to 503.7 kHz very nicely.

73, Dave G3WCB IO91RM

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org
[mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Rik Strobbe
Sent: 02 April 2009 08:09
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: QRSS / beacon test on 503.7kHz


Hello Mike,

I am using a "clone" of the M0BMU design. It is a 4MHz ceramic
resonator VXO, divided by 8 to get 500kHz.
It tunes the entire 501-504 band (in fact 500-505) and after some
warming up it is reasonable stable (drift of less than 10Hz/hour).
As it was meant for CW QSO's there was no need for further
stabilization, I am sure that with some kind of temperature control
stability could be improved significantly.
Actually the frequency stability is best at the lower band end (large
tuning capacitor), so 503.7kHz is not optimal.
I noticed that the VXO drifted up about 30Hz from 21:30utc till
05:30utc, during this period the shack temperature dropped from 22C
to 14C (thus about 4Hz/C)

73, Rik  ON7YD - OR7T

At 00:13 2/04/2009, you wrote:
>Hi Rik,
>
>What kind of resonator are you using? There has been talk of using
>ceramic resonator's on HF beacons but some question if they can be
>tamed down to stay put on freq. Are you using a crystal heater on
>that resonator?
>
>Mike
>WE0H
>/16
>
>
>
>Rik Strobbe wrote:
>>Dear all,
>>
>>I just started a QRSS10 beacon on 503.7kHz (right now 503.705 but
>>it might drift down some Hz over the next hours).
>>The beacon will start every 15 minutes at +6 minutes (so xx:06,
>>xx:21, xx:36 and xx:51) and the message takes about 7,5 minutes.
>> From +6:25 to +6:30 it will be "key down" for the "blue trace" on
>> the G4GWT beacon monitor.
>>ERP is about 200mW
>>
>>73, Rik  ON7YD - OR7T
>>
>>Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
>>
>>


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