The following outlines how I established a portable GPS Disciplined Oscillator for use with my microwave Transverters. The unit is based on the Trimble Thunderbolt and the object of the Project was to allow the “Thunderbolt” to be used in the field as well as in the radio shack.
Prior to commencing the project I reviewed as many articles as I could find on the internet as I was not looking to reinvent the wheel. While there are many excellent ideas appearing in the articles I could not find an article that satisfied my requirements. My needs were quite simple I thought and really centered on a high percentage of usage away from the home QTH.
For portable work there was a need to allow the unit to be operated on 12 volts DC making it compatible with all of the microwave transverters and other portable equipment used by me for field days and portable style operation. In addition there was a need to make the change over process from AC to DC as simple one and ensuring that the unit would also be polarity protected.
“Those of you who have operated portable will know how easy it is, even for the most experienced operator, to make a mistake, in the haste of the moment, when setting up a portable station, to reverse the supply polarity and without polarity protection the ultimate failure occurs! The result equipment destroyed.” The challenge, in fulfilling these requirements, was to make sure that the solution adopted was cost effective. By the way the total cost of my project was under $200 and has resulted in a very functional and flexible piece of equipment.
In developing this project I was determined to use readily available components and to make the unit as light as possible while allowing it to be robust to allow it to survive Field Day activities.
An explanation of the Project will follow shortly.