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Expected distances for a low level mesh

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W6AE
Expected distances for a low level mesh

I'm looking to install a mesh in parallel to a radio link system for an annual public event this year in order to test throughput.  I'll likely be the only person active on it to check connections, but if it works out OK, I'll be looking to expand its use next year (have to work on getting traffic to one node that will be too far for normal communications at this time).

Most of the nodes will be mounted next to tents, and might be elevated 10-15'.  For the outside areas, I'm looking at 5Ghz Bullets with either a short Alfa antenna (dual band - says 9 dB for 5Ghz, or a longer single band that is rated at 12 dB.  The longer antenna has a mounting bracket to make installation easier, the shorter one does not - would have to have some other mount for it. I expect to use anywhere from 3 to 5 of these.  I don't have the time to raise funds to get MIMO for most of these spots.  The entire center of the event is flat, but will have temporary booths installed for vendors and the like.

My question is this:  what would you expect the effective range of a node mounted as such?  I'm trying to tailor the install to include them.  Our end-to end distance will be about 4500'.

In the center, I'll have at least one Rocket with an appropriate MIMO antenna that I hope to have up higher - probably in the range of 20-40' - I know this won't speed up the outside nodes, but our traffic needs are typically slower (right now, we're using Icom D-Star with one of the programs to chat and send notifications). 

I might even be able to gain access to a building at one edge of the event - if I can, I might be able to put up a sector antenna that might bridge things a bit.

Any thoughts?

W6RUF
W6RUF's picture
Clear line of sight between nodes?
Will the outside node antennas have a clear line of sight (LOS)  between them or to the center MIMO node?  Are there buildings or large metallic structures in between?  Are you using omni antennas just to lessen setup time?
Can’t buy a Bullet plus other antenna for less than the cost of an M5 Nanobridge (which are MIMO radios).
The MIMO Rocket at the center, Why have a MIMO if none of the others are MIMO? 
In clear line of sight outdoors I have two M5 Nanobridge radios connecting to two separate mountain top Sectors at 34 to 36 miles.  They stay connected all day every day regardless of rain fog, hot sun etc.
You're on the right track, M5 is superior to M2 if you can’t set antennas higher. Some Omni Antennas have a slight elevated lobe pattern which might be a problem for you In a dense non-LOS situation.
 
W6AE
With the antennas up around
With the antennas up around 10-15', there should hopefully be line of sight to the center node.

As for why the MIMO in the middle when nothing else might be (unless I'm able to use the building I mentioned), it is because I have it, and it can still function in the middle.  It will also likely be the one that is elevated the most over the site, either from a pneumatic mast on a trailer, or on a tripod on top of a semi-truck trailer that is usually right next to us. 

I will take a look at the specifications on the antennas to make sure that I am within their expected lobes.
AE6XE
AE6XE's picture
The max link rates with a non
The max link rates with a non-MIMO or single antenna device is 65Mbps.  If it can use the short guard interval, then maybe 72Mbps in 20Mhz.  Cut these rates in half for 10Mhz channel.   Max data throughput for the applications will be much less than this.   If on 2Ghz, using 20Mhz channel on ch -2 goes out of band edge, have to use 10Mhz.  

Unless you already have the bullets, I'd only get MIMO devices.    A 1 mile or less link, if clear LOS, you should readily be able to get 144Mbps link rates with a clear part 97 channel, more easily found on 5Ghz.

There are numerous people in my area setting up in parks and vehicle antenna mounts or tripods.  But we have the luxury of mountain peaks and hills in the area.   Just recently the City of Irvine RACES 'IDEC' group demoed to the City E-Manager and had 2 park locations in the city, going up ~8  to ~10 miles to a tower site, on 5Ghz MIMO devices.  the downlink to the City PD EOC was 3Ghz, probably another ~8 miles.  They streamed 2 HD video signals from both locations in to the EOC and had a Voip conf call across all the sites all at the same time.  The demo ended with streaming video from an airborne drone flying around the park in to the EOC -- the cherry on top.

Joe AE6XE
W6AE
Thanks for the information. 
Thanks for the information.  I already have several Bullets in hand.  The antennas for the Rocket are more expensive.  I'll see what I can obtain between now and then.  I have a month to have everything in hand, loaded, and tested. Most of my units are 5Ghz.

Our bandwidth needs are going to be low at this time.  We're using D-Star to send messages between locations - it is faster than analog, but the Bullets themselves are going to be faster. 

In any case, I'm prototyping the system this year with the hope we might make greater use of it next year. We will still use the D-Star system for this year as our primary unless we have a failure.

I still need to work on our off-site location to include it - it really isn't LOS due to buildings and trees. I'm considering nodes out between.  There are agencies involved that might have a network between sites - I'm looking to contact those people to see if we can get a tunnel on it for next year.
AJ6GZ
Options

If on an extreme budget, I would go for a Nanostation Loco.  Same price as a Bullet + Antenna, however you've got a 13db directional MIMO antenna.  After that, the full size Nano, another 3-4dBm for another 20 bucks.

But since you've already got the Bullets, go for it!

I recently did an event shooting point to point 5.8ghz 1500' thru a row of vendor ez-ups and rental vans (that weren't there when we set up!), a chain link fence, and the corner of a metal clad building. The clutter that rolled in knocked a good -8-10 off the rssi but it worked. One end was non-MIMO and i forget the data rates we got but it was enough for the 6-8mbps of planned traffic. Both ends were only around 9ft up with 23dBi panel antennas.  It was a last minute non-critical test setup and certainly a learning experience of a compromised environment... but hey only one way to find out how far you can push it!  Since your application should be a true mesh you should end up with connections between closest nodes so you won't need to hit the full 4500ft on one link.
 

W6RUF
W6RUF's picture
Send me a message with date
Send me a message with date and location, Sac is about an hour 30 min drive from here.  Maybe I’ll cruise up just to see it.  The San Joaquin Valley Mesh group has some really good people in it, if you need help we can bounce up there for you no problem.
W6AE
Expected distances for a low level mesh

Thanks to everyone for their input.  I'm keeping an eye on available equipment that I might be able to obtain prior to the event.

W6RUF - you have email.

KD6EPQ - thanks for giving me something similar to that what I might expect.  The node in the middle will be the one elevated the most within our area unless I get access to the roof of a building off to one side. The one side where I'm likely to see vendor EZ-ups to the center will be around 1,300'.  From the center to the other side will be longer (about 2,000'), but should hopefully have less clutter.  I'm awaiting a map of the venue with markings so that I can plan.

I'm looking to have a few directional antennas available just in case I need the additional signal strength. I have one node that will be offset a little that will probably be a clean path to multiple nodes as well - I just want to ensure redundancy.

Thanks everyone!

BTW, depending on what we find, it might be possible that more nodes and/or capabilities may be deployed in the future!

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