2 B5-lites on same pole same direction?


#1

I would like, if possible, to mount a pair of B5-lites on a pole pointing 2.5km away to a similar arrangement. I have an ideal path over a valley, no interference.
My questions are:

  1. Can I get the full speed out of both radio sets, ie is there sufficient separation of frequencies to operate both at full width, it seems like there may be.
  2. How far apart physically should the two devices be separated on the same pole?

Thank you – lee


#2

This is a topic I’d like to see an official answer for…

My impression is, yes, you could put 2 on the same pole pointing the same way. BUT, you would have to maintain frequency separation, and you would likely have to play with the bandwidth and power levels to limit interference.

I think with enough frequency separation those aren’t too hard to address.

That said, what exactly are you trying to do by using 2 distinct radios?
Perhaps there’s a better method?


#3

Well, this is not an official response, but I did lookup the B series resources which give a very good overview of Co-location of radios. Though there is not an exact covering of this particular situation, the principles can be applied. First though the links for a more through and official covering:
http://backhaul.help.mimosa.co/backhaul-faq-gps-glonass

In here they talk about having ~10 feet of distance between Co-located “non-Mimosa” radios. This is essentially what you are going to have by running 2 B5-lites because they do not have synchronization of any kind. (The longer deal is under “What are the guidelines for collocation with non-Mimosa radios?”)

My recommendation would be to use a B5/B5c if you want to get more throughput, if you are trying to have redundancy, then the two B5-Lights will work, but you will want minimally 15 MHz of channel separation and you will want to use as small of channels as possible to minimize interference between the two radios.


#4

Thank you both @William5 and @Bryan1 So factors involved in this are:

  • Existing setup radio 1 pair: 45mb/s (5.8GHz), radio 2 pair: 65mb/s (3.65GHz). Mounting is a vertical pole either side with guy wires. 2 x 10lb radios top and bottom with 12" separation. I would like to reduce the load/weight on the structures.
  • The 2 links are load balanced and redundant with equipment either side of the radio bridge.

The goal is to have 2 radios primarily for redundancy, secondarily for aggregation of bandwidth, 1 gigabit bandwidth ideal.

As I can’t get 10 ft separation and the requirements seem a little critical (for me) for 2xB5’s, I think I’ll replace the 5.8GHz with a B5-lite, that will get us enough bandwidth for now. I can than wait for further product developments and/or ponder a B11 or B24 for the redundancy and hope Mimosa make a 3.65Ghz product in the meantime.


#5

Based on your distance of 2.5km, I think that the B24 might not be a option. The stated limit is 3km, and you’re right there at 2.5km.

I would use the designer that they offer — you’ll get a better sense of what will work, or rather what is more likely to work. The designer is not perfect science, but it is quite good at what it does. I have a 19km link that shouldn’t work, because they state not more than 12km… but, it works fine.

If you didn’t already purchase the B5-Lite, you might consider the B5 instead. We use both, and the B5 is really done quite a job for us. The other advantage is that when you want to replace the 3ghz radios, you can just add another B5 pair, and have the best of both worlds. 3ghz frequency pairs are quite a challenge to work with given the limited channels for that band.

I realize cost is a factor, but if you’re already using 3ghz, you’ll find these are MUCH less costly to move to than it appears given the benefits possible.


#6

@Bryan1 - unless I’m misunderstanding, it seems you are saying 2xB5’s would be better than 2xB5-lites? Why would that be? I’m looking for reasons to justify the budget. $300 vs $1200 to double the bandwidth is a hard sell unless I can provide other reasons.

thx BTW


#7

GPS + bigger and better antenna + you can split your channels and do all sorts of cool stuff with the B5. If the link might have some noise the B5 will perform better in many ways. But if you don’t need the extra speed then you should be fine.


#8

The primary reasons in my view… “–>”

–> 25dBi antenna vs 20dBi (minor difference, but it’s more than 3db so it can matter)
–> IP67 va IP55
–> Collocation vs none
Dual Link vs single
TDMA-FD vs no TDMA-FD
–> 4x4 vs 2x2 MIMO
–> 20/40/80 dual vs 20/40/80 single channel widths
8deg beam width vs 14deg
–> 20w radio vs 15w
Load Balancing vs none
GPS vs none (only applies really for TDMA Collocation)

I have a site that’s 1.5km, and I get a solid connection as just over 1gb thru the connection, so, call that 500mb both ways since the numbers usually shown are aggregate My physical speeds show as 1.733gb. In heavy weather I’ve never noted it below 1.040gb physical.

My B5-lite – not even close to .5km… 867 physical, and 520 true.

On my B5’s I can change a channel on the fly if needed and not lose the link. On B5-Lite, you will lose the link.

edit
The office I have using the B5’s in this example have 26 computers connected, as well as a voice link and a few printers to top off the cake.
They use some top heavy thick client applications as well as the usual array or low traffic applications.


#9

I concur with @William5’s view…

But I’m looking at the idea that you currently have 2 radios following the same path. If you have thoughts of redundancy on a minimal budget, I’d agree that B5-Lite would be the way to go.

But, if you’re planning on future growth, then I would be leaning towards the B5 and it’s better functionality and performances.

Wireless uses only go up, never down, so we built out with that thought in mind. Mixing and matching according to each case, but really planning that we’re always going to need more.

If within range — I’d even go with the B24 in your case because that is a true 1gb connection, not half-duplex like 5ghz.
It costs slightly more than a B5, but no a ton more.


#10

After reading this I’m convinced we should get a B5 and I’ll probably be told to leave the 3GHz as backup.

65mb/s is good enough for emergencies IMO, the higher bandwidth is for internet use, not WAN (VoIP) use which remains fixed.

Thanks a lot for your input, much appreciated.