Rain/Snow Fade for PTP 600

We are doing a PTP project for a customer. The link distance is 40 miles, and the area in Canada that the link would be deployed in experiences heavy rain/snow throughout the year. These two factors have caused me to be concerned that the link may lose significant dB through a heavy rain/snow storm which would render the link unusable.

Does anyone know how to factor these variables into LINKPlanner or if there is reference table for 5 GHz explaining rain/snow fall vs. dB loss and distance? I want to make sure that we have sufficent Fade or System Margin in the event of a heavy rain/snow fall so the link may only be slightly degraded and not lost.

In my experience with 5 Ghz I noticed an attenuation of about 10-15 db on 30 km links in case of really heavy rain.
Snow can be a problem if covering and remaining on the antenna surface, but of course you will use some sort of parabolic dishes with radome, so it shouldn’t be an issue.

Yes, we will be using 4 or 6 Ft. RadioWave Antennas w/ Radome. I thought there might be some reference material to calculate this. Rain MM/Hour -> Frequency -> Distance = Attenuation

I talked to one of the Technical Manager’s at Motorola. He was able to provide me with a chart displaying this very thing. Also, supposedly LINKPlanner considers rainfall for the area when calculating availability.

I have a 30 KM intergrated PTP 400 link with one end on a 1280 metre mountian which gets lots of rain / snow we dont see any adverse affects. The robust modulation modes that the PTP 400 use certianly help. You may see some fade and drop in modulation modes but total link loss is unlikely.

Our link will be just over 60KM and going by the chart we should see maximum of 13 - 15 dB of attenuation in a heavy rain storm. This won’t be enough to lose the link, but it would be severely degraded.