[Biggles]

I remember reading the spec supplied with our microwave link network and in the part dealing with predicted outages, they were never proven to be 100%. Some of the longer distance links (40km+) understandibly were less reliable, but surprisingly the very short hop high capacity links still were under the 100% mark. I have been on microwave link planning courses before, albeit a long time ago, and I suppose there are so many variables that mean a link can never be bomb proof. We used to expect the long links, which often were across high ground to drop out occasionally, but all panic was let loose when one of our main bearers went down, sometimes for a few minutes, then bounce back unexplained. We always used to keep our equipment cabinets locked, just in case a bored and inquisitive site sharer was poking around and switching things off! The other problem is aerial riggers occasionally disconnecting the wrong dish when there are about twenty on the mast to choose from and the cable i.d. markers are missing.
Alan.