Solar extension cables

When I got my VP1 I decided to mount the whole lot on the roof of my house which is not that high as it is basically a bungalow with loft conversion. Now I am thinking of moving the ISS down, leaving the anemometer etc up there. However I really want to leave the solar sensor up on the roof as well. I know I have to make a mount up but what I need to know is how long can an extension cable be for the solar sensor before I get some signal loss? I think I can get the ISS mounted suitably within the 40ft of cable the anemometer has as standard but it would be shaded for part of the day, would this be too much for the solar sensor.

Any views on this would be much appreciated.

I extended my Davis solar to about 40 feet and it’s fine. I’m sure there is some small loss of accuracy but it’s OK for me.