Gas discharge tubes (selection)RF Power
A total of eight gas discharge tubes with different static spark-over voltages are available. To select the correct gas discharge tube, the following criteria must be known:
The required static spark-over voltage (consider the lowest possible voltage from the tolerance range!) is 1.5 times the peak voltage on the transmission line. The following formula is applicable for the peak voltage, if VSWR = 1 @ sea level and 40°C.
For multicarrier systems, the (in-phase) peak voltage must be calculated as the total of all single peak voltages:
This consideration does not involve effects of the modulation. They have to be added according to the selected modulation principle.
The admissible RF power versus the VSWR is shown in the following diagram for HUBER+SUHNER gas discharge tube (valid also for non-ionized equivalents):
* non standard values
With low RF power values (e.g. pure receiving operation in a transceiver system), we recommend the application of the GDT with the lowest dynamic spark-over voltage.
