Alan Melia wrote:

They take several 10s of seconds to reach usable brightness....longer than
tuble starters. No good for short spells of activity as they are only
becomming usable when they are switched off.

Hmmm, maybe this was true until the very last generation of energy-saving bulbs.
I bought a couple of weeks ago a bulb, rated for 85W electrical consumption, and
a light emission comparable (they say on the cardbox) to a normal lamp of 400W,
to give light to my shack, and it comes up instantly at full light.

I don't know how long it will last, it is made in China, and probably it will 
fail
in two or three months, but I paid 8 Euro for it, so it will not be a great 
loss.
But the bulb it replaced (an old one, that took 5 minutes to reach full 
luminosity)
did last for three years... and it still worked, I just wanted a bit more light.

BTW, I haven't noticed any increase in the RF noise, neither on VLF, nor on HF.
But probably having the antennas 25 meters away from the shack, with good coax
cables, helps...

73  Alberto  I2PHD