I wonder if the "channel shifting" feature of the M9 (and 3 MHz BW) can be enabled in AREDN? These are available under a standard Ubiquiti load.
The reason is that I use a pair of nice interdigital filters milled out of a solid block of aluminum and they are tuned to 914 MHz and 4 MHz BW. This lines up nicely with Ubiquiti - but these two choices do not show up in the AREDN mesh.
It should be possible to shift the center frequency, but I was told that 4 MHz is the widest it will go without the passband getting lumpy. Anyway, I would really prefer to leave the filter tuning alone. If the feature is not available, I will revert to Ubiquiti and do something different for the mesh link.
Thanks
Ken
One would think it be easy to do (was some of my first words on the subject) but with the way the open source drivers and 3rd party programs used in a Linux Operating system are written it's really not that easy requires some changes and may not be able to be toggled on and off. I'm not sure I see us putting the effort into this at this time. Not sure what future will bring so won't comment on that.
Do you need the filter ? I know of one site that was using filters on 2.4GHz with Linksys and assumed it was needed for Ubiquiti and they later found out it added no real advantage and only hurt SNR by attenuating signal.
In addition the signal would still be 5 MHz wide which if you mean the filter is only 4MHz wide you would still be in the lumpy rolloff for 500khz each side.
I know by now that it is rare indeed to find something that is easy. But from what I Googled, I think you have to: modify a county table showing the power/frequency/bandwidth you can use in that country and then encrypt and sign it with a key, insert it in the right place and then it becomes available to your application program.
The M900 will be co-located with a 927 MHz repeater (running 100 watts at the transmitter end) so the filter is absolutely necessary. Rockshields might be needed too (to prevent the M900 from radiating garbage into the receiver antenna of the repeater).
>> 900 MHz is the one WIFI band where you find (analog) repeaters sharing the same tower top as the WIFI. That includes repeater linking for the lower bands. If you consider paging transmitters etc., there are a lot of powerful signals to dodge. I imagine that is one reason why Ubiquiti included the narrower bandwidths.
The standard bandwidths on the Ubiquiti firmware include 3 MHz and (I think) 1 MHz. I was using 3 MHz in my testing. 1 MHz is still a lot better than the next alternative of 56 kbps.
I found 900 Mhz was the only band that would penetrate the trees in the direction I needed.
What would be the best way to connect two meshes together using the standard Ubiquiti (or other) software?
Ken
Ah very good points on the strong signals, especially the ones on the site you are going to be using. I can see that you would indeed likely need/want the filters there.
The best bet would probably be to put two two wifi points up running AirOS, treat them as a network link, and run a tunnel across the the link is my suggestion, though I seem to recall the AirOS doesn't support tagged VLAN 1 so may need a smart switch in the mix.
There is a "todo" to provide a backhaul interface (likely vlan3 but may change) that be similar to DTDLink and Tunnel combined in that no tunnel overhead be needed and it wouldn't presume the link to be lossless, but that won't make it in untill next version at the earliest as current beta version is feature frozen. Once that is put in it would likely be the prime method.