I've just been given a 4 foot 36 watt flourescents lamp and HF gear it will be interesting to see how long it lasts and how it copes with the cold in my shack. I notice that at switch on there is a blue glow around the cathodes so I assume it's starting in cold cathode mode so I will be careful not to start it too often and then only run it if I'm in there for an hour or more.

They may be starting fast, but no blue glow (or if it disappears too fast to be seen) means no prolonged cold cathode operation

Some Instant Start ballasts however can run the tubes nearly half second in this mode (estimating what i seen..) and that is not good



Consider this :

Emergency inverters run a 36 Watt tube at about 4..6 Watts, no cathode heating. That is just marginally over the power it takes to overcome the "evil blue" discharge phase, so bad but not THAT bad to the lamp

After one power outage (10 minutes max to battery depletion) of such underpowered run, especially in worst case conditions (weak battery in inverter makes it underpower more), there sometimes allready is some visible blackening on the ends of the lamp. After few such runs a lamp can get RDed...



Half second Blue glow * 120 starts = 1 minute Blue glow

120 starts * 10 = 1200 starts = 10 minutes Blue glow

Start the lamp 4 times a day and you get those 10 minutes in less than a year... And that is the evil Blue glow itself, not some "not so bad" underpowering of the EM inverter

I think mine does the blue glow for around a second I've not timed it yet. It actually didn't do it last nite when I put it on its now in its working position when I saw the glow it was standing vertical on the floor now it's in the more normal horizontal position can this affect it in any way?? Il keep an eye on it and see how it goes.