Our 'ON0WV' repeater system has been running for 3 years with a triband antenna
DIAMOND X6000, as three repeaters ( 2m / 70cm/ 23cm ) were QRV from this
location -
see
X6000 specifications here.
We have experienced that during rainshowers, strong static discharges were noticed, producing QRM on the repeater signal, going from crackling (like a machine gun) to a constant whine, making any QSO impossible.... strange, as the antenna is announced as 'DC grounded'.
After replacement of the X6000 with a new antenna (dual band type X300, as 23cm was discontinued), we have opened the X6000 to analyze status of the 'guts'. No water dripping out .... that is a good start !
But, much to our surprise, the lower end of radiator came loose.... because a small PCB, making the junction between lower and upper end of radiator and acting as a support for small ceramic condensator, was completely burnt through! See picture below ....
This PCB burnout was sure not caused by too much power : never, on any band, there has been more than 50w applied.... So, came to conclusion that the PCB failure was due to the fact that the top radiator section can become loaded by static rain / wind, and then regularly discharges by arcing towards the lower section (only this one is DC grounded!) producing heavy QRM - and this arcing is slowly burning through the PCB !
Suggestion to DIAMOND Antenna Corporation: put in parallel to the condensator a resistor, enabling discharge to ground of static buildup on top radiator.