Just how many hops can we make?

I am wondering if anyone has experience expanding Canopy Wireless service from a primary base station to several repeating stations. My question is, just how many continuous hops can we reasonably make, and at what distances?

We are in a very mountainous area, with high points that serve villages every 5 miles are so. At present we are broadcasting 5.7APs and receiving on 5700SMs, then repeating on another AP to another SM, etc. We are extending service 15miles (3 hops), and are starting to see lots of reregs. Any suggestions or ideas for a better design that won’t break the bank? Is three the max we should attempt? We seem to add about 20-30ms delay every hop.

I noticed the discussion from a few days earlier regarding a similar topic, but they were all using back hauls. I wanted to keep using APs because of their dual roles to service some clients as well. These are really small villages, and we often broadcast 2.4 from the 5.7 SM to keep it affordable for folks.

You can add hops until the latency and/or throughput are unacceptable. If your terrain permits, you can control the growth in the number of hops by using a single primary AP site for distribution to all secondary APs. You may need to install a single BH link to the primary AP site if it’s at a remote location. This combination yields 3 hops to any customer.

The re-registrations you’re seeing are unrelated to the number of hops, at least not directly; they are instead the result of an RF-related problem on an individual hop. Because you have created a daisy chain of links, proper synchronization becomes more difficult; you may need to reevaluate the timing source and frequency selection (both band and setting) for each hop.

If you’d like some help, post a more detailed description of your Canopy network.

In a mountainous region I probably would not use 5.7s for anything but backhaul as they are pretty much limited to perfect LOS.

I would use 900’s as they have excellent non-LOS performance at shorter ranges which will allow you to capture more customers per AP. The 2.4 also have good performance through some foliage, but definately cannot get around hills like the 900’s can.

You really want to try to keep your latency as low as possible - this is where the Backhauls make sense.

You could possibly offset the cost of the Backhaul by selling VOIP. You can partner with a VOIP provider and resell it as your own brand. Customers will probably want to keep a basic lifeline for emergency 911 calls just in case your network goes down but in all reality your service would likely be more reliable.

That being said, I can offer a few things to look at:

Make sure you are not using overlapping frequencies from one tower to the next. The manual describes which freq’s are non-overlapping.

I assume that you have used SM’s as RF spectrum analyzers and made sure you are using the quietest frequencies? You will want to check at different times on different days to make sure there is not a periodic transmitter operating.

What version of software are you running? We noticed a huge improvement in latency by migrating to 6.1 or later. Are your radios part of the Canopy Advantage Platform? That makes a big difference too.

Do your AP’s and SM’s have public IP’s on them? If so, you will want to change to a private network for the Canopy equipment. We have noticed a substantial improvement in network performance after getting the public IP’s off the Canopy’s.

Just FYI Check these out:
http://cgi.ebay.com/Motorola-Canopy-Ant … dZViewItem
Could come in handy when you are a little too far for just an SM, but still a little too close for a reflector.

Hope this helps

I can already tell this is going to be a great place for an isolated soul in the mountains of the Rockies such as me to get educated by real world users. Thanks so much for your recommendations. This weekend I am going to look closely and the recommendations, and, can you believe it, attempt a CNUT install on redhat. Our Software Version is still CANOPY4.2.3! I’ve just been so shy about upgrading. we had a really bad firmware experience where 4 of our radios were rendered useless, but I’ll save that story for a new topic called FIRMWARE JITTERS.

Jerry, I really appreciate the information regarding performance improvement. We are just now playing with VOIP, and our tests have been disappointing (again, I’ll save that for a new topic) Perhaps the firmware upgrades, non-public IP addressing and those cool new antennas may help use resolve this problem… after we figure out the GPS issue.

Best regards,


Teknix, you’ve got a new customer! I am looking forward to my order.

Here’s an example of what I am seeing on the 2nd of two primary base stations. The backhaul is just two miles away.
LUID: 005 : State: IN SESSION (Encrypt Active)
Site Name : Ridge Tower 1
Software Version : CANOPY4.2.3 Jul 23 2004 11:13:49
Software Boot Version : CANOPYBOOT 3.0
FPGA Version : 062403 (DES)
Session Timeout: 27, AirDelay 494
Session Count: 25, Reg Count 25, Re-Reg Count 33
RSSI (Avg/Last): 953/953 Jitter (Avg/Last): 2/1 Power Level (Avg/Last): -71/-71

now, this is our very first hop, and when I run pings, I’ll drop roughly 7% on a 1000 count. I reset the AP 39 days ago, BTW

This re-reg count has GREATLY improved since we changed the AP Sync Input to Sync to Received Signal (Timing Port) instead of Generate Sync Signal, but still, to drop so many packets… I am left wondering.