Old Radar / OFCOM EMF calcs.

[IanCC]

For anyone who comes this way in the future. It looks like the calc. in my original post is correct.

I communicated with Furuno, who agreed with my calc as far as 0.1296 which is the most difficult bit. When i pointed out that that was the time in seconds whereas for ofcom it needed to be minutes there previously very forthcoming communication ceased.

They had said they were certain that rotation shouldn't be adjusted for, but seeing how the ofcom seperation distance is 0.1 metres using the above calculation there doesn't seem to be any need to reduce it further.

 

[IanCC]

for anyone interested. Furuno sent the following:

Hi Ian,

Well, after much time and working out gains etc for the older Furuno Radars we have finally come up with the results as follows:

Input parameters
EIRP		=	2000000​	Watts
Max transmission time: My equipment transmits Y % of the time in any six minute period		=	0.0019​	%
Operating frequency		=	9410​	MHz
Calculated result
Separation distance R		=	0.88​	m

It took quite a few of us locally, and in Japan, to get this right so we are confident that the above is correct. The main issue with the OFCOM calculator is it really caters for omnidirectional antennas which of course a Radar is not so there were a few more variables to consider.

Luckily the safe distances for the Radars from the last 10-15 years are in the front of the operators manuals.

Best Regards

Brian Martin
Furuno (UK) Limited