[GPS_Standard] Replacement 10 MHz Oscillators

[Bert, VE2ZAZ]

Hi P M,

I am afraid this kind of stability will not be good enough for long term
control. Remember that the end-to-end electronic tuning range on the HP
units is 1Hz! GPS Systems will disciplin these oscillators for a few years
before requiring re-alignment with the adjustment screw. A 10Hz end-to-end
range will still work with my GPS-Derived Standard design. I have not tried
a wider tuning range though. Regardless, this would mean that after a few
hours you would lose the ability to disciplin your oscillator.

Designing a good OCXO is a very challenging task... You need to understand
the physics of crystals. Selecting the right crystal cut and optimal
operating temperature requires knowledge beyond most hobbyists's abilities.
You also need to promote the right oscillation and reduce the spurious ones.
I leave this to experts. There is nothing wrong about trying though... And
besides, I don't know your level of expertise. :-)

Have fun...

Bert, VE2ZAZ

----- Original Message -----
From: "P M Gant" <ha5rxz at gmail.com>
To: <gps_standard at mailman.qth.net>
Sent: Thursday, November 08, 2007 3:15 PM
Subject: [GPS_Standard] Replacement 10 MHz Oscillators


I have spent the last week experimenting with replacement homebrew
oscillators for use in the GPS standard. After some work I now have a
fixed 10 MHz oscillator that drifts less than 3 Hz per hour after warm
up, this unit is single ovened but well insulated from the outside
world.

My next task is to turn this unit into a OCXO so I am looking for tips
about the recommended +/- frequency spread, control voltage and types
of varicap to use. All suggestions are welcome.

HA5RXZ
______________________________________________________________
GPS_Standard mailing list
Home: http://mailman.qth.net/mailman/listinfo/gps_standard
Help: http://mailman.qth.net/mmmain.htm
Post: mailto:GPS_Standard at mailman.qth.net