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
Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm
|
