A 47.8-mile 3.4 GHz AREDN MESH link was brought online today linking Anchorage to the Yetna area. A few weeks ago, Bryan Emerson, KL4A, checked in with me to see about hosting a MESH node at his remote homestead in the Yetna area. After running some path studies and figuring out a technical solution, we decided to deploy a 3.4 GHz Ubiquiti RG26 dish with M3 Rocket radio to his site.
Bryan’s plan was to mount the dish at about 70 feet up his Rohn 25G tower to clear the local trees in order to get a true line of site to our Site Summit node. We built a Cat5e cable long enough to get out of his shack and up the tower and turned the unit on. Initial results showed that the remote unit could see our Site Summit and Hillside South nodes in Anchorage, and vice versa, but the signal to noise ratio (SNR) was not adequate to provide any actual data throughput. Bryan eyeballed the dish from the ground and decided that it looked like it might be pointed a bit skyward, so up the tower he went again. This time, he had a ground crew (his wife!) monitor the signal strength as reported by the radio on the web browser. He managed to get about 6 more dB of SNR wrung out by improving the aim, but this still wasn’t quite enough to do the trick.
At this point, things were looking pretty shaky and I was worried that we were out of luck. But, fortunately, I gave our MESH Mentor, Tom Delker, K1KY in Smyrna, TN a call to discuss. Tom suggested a couple strategies to try to make this work. First, we elected to decrease the link bandwidth from 20 MHz to 10 MHz. Second, we changed frequency to be clear of other frequencies were using for the MESH system. To affect this change, we had to consider 5 other nodes on the network and had to make similar changes to those units. When it was all said and done, we had it! A solid 6.5 to 9 Mbps link!
Tom reports that this is the longest MESH link he’s aware of our connected networks! (UPDATE – 3/1/2019 – turns out to be the 2nd longest link….just barely… the record is held by Andre, K6AH) And this wasn’t even a dish-to-dish link! It was a dish to sector antenna link! We know that a dish-to-dish link would absolutely have better performance, but we are happy with our results! Maybe a dish-to-dish link will follow?!
Many thanks to Bryan for hosting this node and doing all the leg work at the distant end. Thanks to Tom Delker for his solid advice and oversight. More to follow!
Kent Petty, KL5T
Anchorage AREDN MESH Network Manager