Guys
Newbie to the forum, Hope to chat to you all for a long time to come
Looking at putting a longrange BH probably looking at multiple BH units
Could be a couple of hundred KM in 3rd world desert Location
Has anyone done this before?
What sort of distance is honestly likely?
Number of Users likely to be fairly high
With IP Telephony VOIP SIP G729
What top Tips do any of you have
Dave
Guys
This solution will likely be daisy chaining from one tower to the next
with subscribers at each tower connecting via a lan solution
Has anyone done this, ???
Dave
It could be done. For such distances you will have to use conectorised BHs and you will have to do calculatinos for the size of the parabolic antennas. There is link calculator on this site.
For the Voip, keep in mind that if you use the netowork for voice new rules aply. For example, BH20 will never go to the max of 14 mbps. The limit will be 3000 pps.
Erkan
Much appreciated for the response.
Can you point me in the direction of papers on this subject
with respect to BH and Voip
The Daisy chain effect of installing numerous BH links will obviously
be cumulative. Therefore the entire system will be at 3000pps
as you say.
David
Erkam
So we are talking 3000pps at the 64byte per packet rate of wireless
limit imposed in the canopy network system???
Dave
What are the hops are you planning. Do you want to go with BH10s and 20s or OFDM radios? If you give more info, we could suggest more.
canopy BH 10/20 dont attempt more than 30 miles, though I had a test upto 88 miles, but I am against having such long hops with BH10/20s. If you want really long hops, OFDM radios are better options and they handle more pps than the canopy BH10/20
Well, it is likely to be consecutive hops and this could be over 200km.
Therefore a sequence of BH will be used between sites down a chain
of locations.
Much like you would implement a Microwave backbone across multiple
microwave shots, but using Canopy BH instead.
The OFDM is a likely candidate. However Have you used this type of topology. a-b-b-c-c-d-d-e-e-f type linking all along a set of locations
strung across the desert highway. at each location a number of phones
and computers will be stationed and the link continues down a further BH to the next location.
Dave
We have used 3 hops, ab, bc, cd and the all the hops are within 45 km; we have done with 10 mbps backhauls, which run effectively even in C/N of 3 dB. We have very small bandwidth requirement.
If you go with BH20, you should at least have 10 db of margin. The receieve sensitivity of BH20 is -79. You should have enough antenna gain to have a fade margin of more than 25 dB, if you want to make 40-50 km hops.
As long there is enough fresnel clearance, enough fade margin, and enough throughput needed for your needs, you should be fine having a daisy chain of 5-6 hops.
nepalkin
cheers matey, The requirement at each drop will likely build over time,
a PC and a IP Phone at each is the minimum at that would be required.
i will bear in mind as you say the 10dB margin very important.
what do you have at each site?
I expect that the site will grow, and therefore the solution will not
last long and require replacing.
I will speak to motorola on Monday and ask their advice on this.
Dave
All,
thanks very much for your support thus far
i have found out that the idea is to run
28 (twenty eight) BH hops out into the desert
The hops will have a PC and an IP phone on each hop
This should be interesting.
Has anyone done this type of link before over this number of hops
Dave