Using an SM for an uplink from provider

I am woking on starting my own little WISP, to extend to some of my friends and family in the community. I have an ideal tower at about 80ft on a hill. About a mile away I have a “friend” that can get high speed internet access. I live about 1200 ft from the tower.

One of my plans is to get a cyclone type omni AP to mount to the tower and to start with two SM’s one on my house and one on my friend’s house. I will get some type of “business” internet account at my friends side, but the question I have is can the equipment (especially the SM) be used in this fashion?

I also have the option of receiving wireless access from another WISP, but my house is too low. The option would be to mount a reflector and SM on the tower. (Distance is 8.5 miles) I have tested this, and received the following data (RSSI = 858-908, Jitter varies 1-4) The one thing that concerned me while testing this was I lost connectivity for about 30 seconds twice in about 1 hour. I know I have a ridge between the provider and myself, and I barely sneak over it. Is this RSSI to close to the 700? It is a 2.4Ghz system.



Yes, you can use an SM for your connection to the Internet. You should set the AP’s DataDown to 50% (75% is the default) to get the best speed. The agregate speed for all users, however, will suffer with this configuration, for two reasons:

1. The uplink travels to the AP over shared bandwidth.

2. Every data packet essentially travels this shared bandwidth twice. A packet from the Internet travels via shared bandwidth from SM to AP, and again from AP to the user’s SM. This assumes both SMs are registered to the same AP.

Bringing service directly to the tower would be a better solution – if the service available to you meets your needs. To bring service from your friend’s house, Motorola’s preferred configuration would be to install a pair of Back Haul units from your friend’s house to the tower, then connect the tower’s BH to the AP. The BHs and AP need to be different frequency bands; e.g., 5.7GHz BHs to a 5.2GHz AP; using 5.7GHz for both, even when different frequencies are selected, may or may not work and is not supported by Motorola.

To save some money, you could actually start with a standard AP with a 60-degree directional antenna. Install it on the tower and point it towards your friend’s SM for the primary link. You can very likely get the SM on your house to work since you’re so close, even behind the AP. I have one SM currently operating 1764 feet (according to the SM) behind an AP; the signal strength is marginal (-80 to -82 dBm), likely made worse because of some trees, but the connection is reliable… so far. Another thing to consider is that you can likely get two used APs, and maybe even new APs, for less than the cost of a single Cyclone Omni.

Fortunately, you should not need a CMM (a significant additional cost) for this small Canopy network unless:

A. There are other Canopy units operating nearby on the same frequency bands. If the competing Canopy units are at least 5 miles away, they’re not an issue. You may or may not have problems when they’re closer; there are posts in this forum where technicians have made them work as close together as 30 feet, but this is a recipe for problems, according to Motorola.

B. You install multiple, same-band APs on the tower. If you install an off-band BH link, however, you can use the timing signal from the BH on the tower to provide timing for the APs.

Good luck!

First of all thank you very much for your response.

If I only have 3Mbps or less of Bandwidth it shouldn’t matter because the system handles approxamately 6Mbps actually throughput correct?

Someday I would like to have more bandwidth than this, at that time I would definitely look into adding a BH unit. Unfortunately where my tower is bandwidth isn’t.

Do you dislike omni-directional AP’s? I would like to run a 2.4GHz AP, but if I use another wireless provider, there system is running at 2.4Ghz and the SM from them would be about 8 to 9 ft away from my AP. I know I lose a lot of range moving to the 5.2 euipment, but does the 2.4 equipment penetrate through foliage a little better than the 5.2?

Thanks again,


Yes, 2.4 is better than 5GHz for foliage; if this is a concern, however, 900MHz would be a much better, albeit a bit more expensive, choice. You need to consider all factors – cost, range, interference, NLOS, foliage, number and direction of customers – to make the best choice for your situation. The best choice, unfortunately, might not fit your budget.

Even if you don’t bring 2.4GHz service to the tower, 2.4 may be a bad choice for your own service because of the interference from the competing system when trying to reach your customers. 900MHz is also problematic because of interference from neighboring frequency bands (paging and cellular) and city utility SCADA links often in the same band.

I don’t have a problem with an omni on the AP, just with the premium price for a Cyclone conversion unit. I suggested the possibility of 1 or 2 standard APs simply to keep the initial cost down. I admit this may be shortsighted because of the limited directional coverage.

If you proceed, please keep us informed of your system’s performance.

Careful climbing the tower!

I will definitely post back. Thank you for your help!

I have decided to get my bandwidth from another provider about 8.5 miles away, and I have my 2.4GHz SM near the top of my 80’ tower I put the rest of the equipment (except for the SM) into a 18" x 18" x 6" box to protect it. It isn’t outdoors but in a very unclean steel building. In the box I have a isobar surge protector with the Adapter for the SM plugged in, and two more adapters for the small switch and the 802.11 WAP. (The place the box is in is hard to get to so the 802.11 is just for trouble shooting with a laptop.) Even without the cover on the Power Adapter for the SM gets hot to the touch. If the cover is on the box it gets even hotter. (Hotter meaning touchable, but not for very long). I need to check into the supply voltage, but that is the only idea I have. Unless the 110’ to the SM is too much? I would accept any thoughts



The SM can be 100m (300’+) from the power supply. If the PS is too hot to handle, then maybe it’s bad or, as you suggest, the voltage could be high. You could try the Canopy international power supply (100-240VAC input), but they’re tough to find in the U.S. I bought one on eBay for $35 with shipping; it’s a switching PS, instead of a transformer, so the waste heat is reduced.

Temperature, hot or cold, can be an issue for all of the stuff you’ve put in the box. Metal or non-metalic enclosures work best when it’s hot; 18x18x6 would run $50 (painted steel) to $100 (non-metalic). If you’ve built a box out of wood, the wood could be adding too much insulation. has free shipping on Adelet fiberglass enclosures – “For a Limited Time Only!” They also have enclosure coolers, but they’re expensive. The cheapest enclosure heater I’ve found is from has free software you can download to calculate heat dissipation.