Next Generation Beacons

1 GHz VCO-PLL Clock - CVCO55CX-1000-1000 ADF4107

Overview VCO-PLL DDS GPS reference Distribution amplifiers Service management Sequence PI4 Software


Emanuele, IW9GDC - "... I can really say that this hardware is actually the best ever made ..."


The OZ7IGY VCO-PLL board is heart in the Next Generation Beacons hardware but cal also be used for other clocking purposes. The VCO is locked by the PLL that is locked to a 10 MHz signal from the GPS board.. The use of GPS synchronization ensures accurate frequency. The output level is 0 dBm that can be fed directly into the DDS board or to a 1 GHz distribution amplifier if more than one DDS board needs the 1 GHz clock e.g. on a multi beacon site.

The VCO-PLL board uses an Analog Devices ADF4107 PLL that is controlled by an Atmel ATmega328 and a Crystek CVCO55CX-1000-1000 ultra low noise VCO. Alternatively a cost efficient Sirenza VCO190-992T VCO.

The VCO-PLL board also features an in-circuit serial programming (ICSP) connector for updating, configuration and service management.

The VCO-PLL board fits into a standard tinplate box or a milled alu-box.

The VCO-PLL board may also be used for other purposes where a 1 GHz clock is needed.

A 1 GHz distribution amplifier board is also available in case you want to connect more than DDS board, i.e. you want to have more than one beacon on the air.


A software package is available for setting up and managing the VCO-PLL unit.

Software support is provided on the above package. From time to time new functionality is added under tight version control. The package is available with both source code and a compiled .hex file. This way specific modifications may be applied for any given application.

When cycling the power supply to the VCO-PLL it is recommended to wait at least ten seconds to ensure all capacitors are properly discharged.


DC characteristics Unit Notes
Voltage 7,5 V - 15 V  
Current 110 mA  
Power consumption 1,5 W  
RF characteristics Unit Notes
10 MHz lock >-10 dBm Datasheet for ADF4107 says -5 dBm to +5 dBm
Frequency  1 GHz  
Output power 0 dBm  
Second harmonic <-30 dBc  
Third harmonic <-50 dBc  
Unwanted spurious <-70 dBc No 10 MHz reference signal found
Phase noise Please see plots below  
Ports Connector Notes
Supply 2 pin Molex  
10 MHz input BNC female  
RF out SMA female  
1 GHz lock TOSLINK (optional) A two or three pin Molex connector will also fit
ICSP 6 pin header Standard Atmel configuration
Service USB B, female  
Mechanical Unit Notes
Size 54 mm x 110 mm Fits into a standard tin plate box. Box is optional
Weight 45 g  

One LED indicates when 12 V is applied and another LED indicates when the PLL is locked.

Phase noise for the high performance Crystek CVCO55CX-1000-1000. Source: Crystek datasheet.

Phase noise for the low cost Sirenza VCO190-992T. Please note that the noise performance is limited by the spectrum analyzer, HP8593E.

Frequency stability vs. time for the low cost Sirenza VCO190-992T.


The price for an assembled, tested and ready-to-use VCO-PLL unit with a Crystek CVCO55CX-1000-1000 VCO is 1923 DKK* (~263 EUR).

The price for an assembled, tested and ready-to-use VCO-PLL unit with a Sirenza VCO190-992T VCO is 1020 DKK* (~137 EUR).

The time used for manual assembly and testing is two hours using solder paste stencil and oven soldering.

The price for the optional TOSLINK transmitter is 30 DKK* (~4 EUR).

The price for the optional metal sheet is 80 DKK* (~11 EUR).

The price for a VCO-PLL PCB is 210 DKK* (~28 EUR).

Example of a milled alu-box showing RF out at the top left. In front is from left the PLL lock LED, 10 MHz input BNC, PLL lock TOSLINK opto-transmitter, USB port and 12 V LED.

Unfortunately we no longer able to supply the milled alu-box.

Please contact us for a partially assembled unit or hard to find parts.

Additional shipping and money transfer cost applies.

*: Prices are subject to change due to exchange rate fluctuations.


Operational troubleshooting

Here is a guide to troubleshoot an operational beacon including retrofits.

Further information

Please contact Bo, OZ2M, at my call sign @ this domain.


Bo, OZ2M, www.rudius.net/oz2m