YO4HFU
GPSDO VE2ZAZ

 

under construction 06.2020

 

 

Modified version of VE2ZAZ GPSDO

- More square wave outputs: 0.5MHz, 1MHz, 2MHz, 2.5MHz, 5MHz, 10MHz
- Additional sine wave output: 10MHz
- Replacement of LTC1485 by 74HC04
- Replacement of output driver MC3487 by 74HCT541
- Simplified filter stage for 0...5V OCXO tuning range

VE2ZAZ GPSDO use 1pps GPS receiver. OCXO frequency is controlled by uC software FLL. VE2ZAZ MonTrol software helps for GPSDO control and status monitoring.

Note about 1pps GPSDO
- Good quality OCXO or double OCXO is required. If LOCK status can't be steady achieved, then is better to replace the OCXO. I have bad experience with Bliley NV74A 10MHz OCXO. Two pieces were tested with same bad result. After OCXO replacement by KVG oscillator, the FLL LOCK condition was fast obtained.
- For very high accuracy the system needs enough time for stabilize (hours, days).

 

 




Schematic VE2ZAZ GPSO
Connector Wiring
PCB

 

 


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