28 dbi Parabolic anntnna

[cehan]

hello
my question related to high gain Parabolic Antenna 28dbi for wimax coverage reception
where my house is far from nearest wimax antenna (Tower) approximately 10 km..and i dont have wimax signal at all...i tried 24 dbi and i get into setting page that is 198.162.2.1 but it said that some setting connected most not. and signal level was so low...
is 28 dbi Parabolic Antenna solved the problem...or it is not just using high gain antenna to receive wimax signal can solve the problem.

 

[davenn]

hi cehan
1) do you have line of sight view to the wimax tower ?
that is ... no trees, building, hill ridges ?

if not, there in lies your problem. 2.4GHz is very line of sight and you would need a good path between you and the tower

just a thought

Dave

 

[cehan]

thanks Dave
there is line of sight, which means there is no vegetation or hill ridges.
is this means that 28 dbi parabolic antenna can solve the problem of receiving wimax signal or coverage from the tower.

 

[davenn]

It might do the trick

something I meant to ask in my last post ...
you didn't comment on how long the coax from your antenna to the modem ?

you need really good coax at 1GHz and up losses get high very quickly
something like LMR400 and less than 10 metres

something else you also need to consider ....
the tower transmitter is probably several 10's of Watts say 20 to 40 W
where as your modem transmitter is probably less than 1W
And your modem receiver may "hear" the tower transmitter my your substantially lower power modem TX
hasn't enough power to get back to the tower


Dave

 

[D.A.(Tony)Stewart]

Cehan, In order to solve your problem, you need to understand path loss of signal levels may be beyond your expectations. This range of transmission is normally performed by 50K$ microwave towers with big Andrews Dishes.

I would start by finding a program ( in Linux or XP ) that can read your wireless modem adapter's Receiver chip using a signal called the Received Signal Strength Indicator (RSSI) in dB. (THe bars indicator in WIndows is not very useful) , I haven't seen any wireless Routers provide this info, ( unless you can find a Telnet solution to the Router's Linux firmware )

Without this data, you are unable to get a handle on the problem.

With this data, you can see signals down to -100dB but need -75dB for reliable 11Mbps communication.

WiMax is "a standards-based technology enabling the delivery of last mile wireless broadband.

It does not guarantee anyone can receive at 10 km.

Alternate solutions are a daisy chain of routers which can act as repeaters using RIP protocol from friendly people who are willing to participate. I saw this in practise in border cities on the North Island of New Zealand along the West Coast, so Wifi can reach all the beaches area and downtown small villages. Only MAC registered Routers could tap into the network using RIP protocol.

Another solution might be Ham Packet Radio which I know started in Canada with 64kbps modems around Ontario here over 20 years ago. I haven't looked into it since.

If you could give any RSSI dBi level at some distance, then tell us what you have tried, then a solution might be possible, but without this, you need local support.

If you expect any answers here, you need to provide a LOT more info on hardware, software, and test results.

 

[vfone]

28dBi gain dish antenna definitely should solve your wireless communication issue at 10km distance, even your WiMAX system works in 5.8 GHz band (and not lower bands as 2.5 GHz or 3.5 GHz).
The only problem when using dish antennas for terrestrial communications is that they have very narrow beamwidth, and to make a proper point-to-point connection, you might need a kind of spectrum analyzer or a strength meter. Also you have to take care about Fresnel zone, avoiding big objects near the antenna following the recommendations in the link below:

https://en.wikipedia.org/wiki/Fresnel_zone

 

[fiwi]

,, vfone, he's right ...

 

[cehan]

As far as i remember it was -76dbm.

 

[tony_lth]

the sensitivity is related with modulation plan, what is it in WiMax?
64QAm is much different from 16QAM.