AP control of SM TX power

Doesn’t seem to work on PMP100’s, in this case 900MHz running 11.2

is that true, or am I missing something.

Thanks in advance,

Homer W Smith
CEO Lightlink

Working fine here in 11.0.1 on a 900 omni, don’t have anything newer deployed. Looks like the clients on this AP are 9.3 or higher. Definitely works on 10.5 clients, I haven’t looked at the 9.3s

What versions are your SMs?

There are 9 clients, all running P10 11.2 FPGA 111010

Of these some are running at -80 as requested by the AP,
and the others are running at their normal output of -55 or whatever.

I am trying to get everyone down to bare minimum to minimize reflections and
multi path distortion off of valley walls or whatever. It seemed to help a few
stabilize and stop session counting.

Others are still session counting, even ones running at -80, and I have the
AP set to 10db, so its waves don’t reflect all over the place.


How close are the -55 ones? These things can only turn down their TX power so much. If they’re only across the street you might need lower end antennas or attenuators.

Also, -80 I find very very low for 900 MHz. Since there’s so much noise it’d be really hard to maintain any 2X efficiency and them baby monitors/video senders could become extra deadly. I’d suggest -70 or -75

right, thanks for the closeness tip, I will check that out.

No noise here, this is primeval woods. Will watch out for the
baby monitors however.

Probably I should talk to all of the customers…


Not so fast :slight_smile: Your other posts say you are in NY - about the only place you can get away from 900 MHz noise is in the middle of the Pacific. I think at this point you’d even have to coordinate frequency plans in Antarctica lol.

900 MHz is used in a lot of things that consumers have and don’t even realize it. Video senders, wireless alarm and security gear, and the cheap cordless phones. I had a VTech phone that was sold as 5.8 GHz. In reality it was 5.8 from base station to handset, and 900 MHz on the return path. Don’t forget about all these fancy smart power meters, either.

Another thing that is more apparent in 900 MHz is self-interference. With the time delay of signals bouncing around in the vicinity of an omnidirectional AP, it’s very possible that your -55 client’s signal is reflecting off of something and interfering with your -80’s. With 900 MHz passing through and penetrating so easily it’s pretty easy to end up with a mess. This is why pretty much every other vendors’ 900 MHz sucks in comparison to the Canopy FSK full power, low-bit-density stuff.

The Canopy gear has a low end receive sensitivity of somewhere around -94 dB. 1X operation requires a minimum of 3 dB SNR to get basic function. Won’t be great performance but it will work. 2X required 10 dB SNR. So, assuming there is no noise; reflective surfaces like rocks, steel, or water; or any weather effects like thermal layering and rain fade; the absolute lowest 2X you should (in theory) be able to get is at -84 dBm (ish)

A little story about interference… we have an omni of our own sunk into a sort of gulley or valley. Was running fine for a couple years with less than a dozen clients. All of a sudden these two houses were having horrible problems that looked like interference. Couldn’t tune it out, spectrum analysis just showed a mess, couldn’t find any interfering equipment at all. So during one site visit, the our customer got permission from the neighbors who were gone for a day or two to kill power to their house. Our tech went over and did just that… presto, service for all! No idea what was causing that and it’s never come back.