[Amps] Cell phones, digital cameras and RF

Roger (K8RI) k8ri at rogerhalstead.com
Mon Mar 5 12:43:06 PST 2012


On 3/5/2012 12:40 PM, Fuqua, Bill L wrote:
>    How many times have you taken a picture of an amplifier tube glowing very red with the cover removed and with a cell phone or digital camera?
> I have done it a number of times and yet the relatively intense RF electric fields seem to have no effect. I have taken photos of my 4-1000A amp with
> bright red plate and probably 6 or 7kV p-p rf only a foot away or so.
> They must be very well shielded!

They are poorly shielded, but their operating frequencies and physical 
construction makes them pretty much immune to HF.
I've never used the camera in the cell phone because no matter how many 
pixels they brag about they are limited by the laws of physics and that 
tiny lens.
Even the digital SLRs are limited by the lens but with those you can get 
the equivalent of a good 35mm film.

The camera in the cell phone is "handy" for some things but not for 
images you wish to make full screen on the computer or prints that are 8 
X 10 or larger.  At least I've never seen one. Some smart phones have 
promised to take multiple images and  combine them for resolution.

73

Roger (K8RI)


>    73
> Bill wa4lav
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