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MyThoughts
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Nstreme Dual Questions?

Tue Sep 05, 2006 4:20 pm

Before I go switching one of my PtP link to nstreme dual I had a few questions:

1. Does the tx/rx-frequency have to match at both ends or does the rx interface automatically follow the tx host?

2. What is the best way to fail-over to one interface if the other fails, is it built in? or do you need to script?

3. The link I want to switch over is not feasible to do in 5ghz range (already tried), does Nstreme dual stay stable and preform ok if both tx and rx radios frequencies are in the 2.4 ghz range?

4. Does anyone have any recommended configurations for doing this with RB532's (i know 800Mhz processor is recommended, but I am changing a bonded link to this, I don't want to change hardware), ie. framer policy/limit settings?
 
jober
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Wed Sep 06, 2006 5:36 am

I did a screen shot of the dual nstreme interface in winbox. I hope this helps.

http://www.dslreports.com/forum/remark,16848002

Also I don't think you could run the link in 2.4ghz only. The docs say that you need 200mhz of channel separation. Dut then again I haven't tried it.
 
Connor9220
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Wed Sep 06, 2006 8:20 am

I don't understand why you need 200mhz separation.. What does Nstream Dual do that requires that much separation? You would think if the channels don't overlap, that would be enough.. I've got some Nstream dual links up and running, and don't have 200mhz, and they suck when you send and receive at the same time.. It's almost useless. MT can you all give some insight on the need for that much separation and what your doing that would cause us to need that much?
 
complete2006
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200 MHz separation

Wed Sep 06, 2006 9:54 am

If you don't understand why 200 MHz separation is neccessary then look on the hardware design of the WLAN cards or better look at professional ptp-microwave equipment. Thy have a separation up to 1080 MHz.
 
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dbostrom
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Re: 200 MHz separation

Wed Sep 06, 2006 3:38 pm

If you don't understand why 200 MHz separation is neccessary then look on the hardware design of the WLAN cards or better look at professional ptp-microwave equipment. Thy have a separation up to 1080 MHz.
Begging the question, how is that we have 802.11a and/or 802.11b equipment colocated w/far smaller channel separation within the respective bands and working quite well?

And what about running nstreme dual w/5Mhz channels? Do we still require 200mhz separation, the same as much larger nominal occupied bandwidths? If so what's the rationale? It can't be magic so there's got to be an explanation solidly rooted in physics and/or crappy transceiver implementation.

I suspect that running the two sides of the connection on opposite polarities with antennas of sufficient gain and separation to produce strong rejection of cross-polarized signals would be of some help here.
 
miahac
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Wed Sep 06, 2006 4:02 pm

I know nothing of this but I suspect the 200MHz seperation mentioned is only required for a dual polarized antenna. If you are running 2 sepearte single poles seperated by several feet, it may not be required. Please flame me if I am wrong.

That brings me to the following question.
Any suggestions for the following configuration?

I am getting ready to set up 21 mile link (34km) from a 155' (~50m) rooftop to a 100' (~30m) tower. I will need a minimum 10mb down and 5mb up usable bandwith. I was planning to use a 532 on each end with 2 x sr5 each and 2 pac wireless 32dbi on the rooftop end and a single 28.5dbi dual polarized radiowaves on the tower end.

I can go with a PC system instead of rb on the rooftop end with little effort but on the tower end I would need 2x150' (50m) of LMR to do that, and loose 2/3 my signal into resistance.

Also I live in Kansas. Here almost every day is 15-20mph winds in the afternoon. Storms every month have 60mph winds. Wind load and structural integrity is almost as important for reliability as signal.

The rooftop side will have more local interference because it is downtown.
 
jober
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Wed Sep 06, 2006 5:12 pm

I know nothing of this but I suspect the 200MHz seperation mentioned is only required for a dual polarized antenna. If you are running 2 sepearte single poles seperated by several feet, it may not be required. Please flame me if I am wrong.

That brings me to the following question.
Any suggestions for the following configuration?

I am getting ready to set up 21 mile link (34km) from a 155' (~50m) rooftop to a 100' (~30m) tower. I will need a minimum 10mb down and 5mb up usable bandwith. I was planning to use a 532 on each end with 2 x sr5 each and 2 pac wireless 32dbi on the rooftop end and a single 28.5dbi dual polarized radiowaves on the tower end.

I can go with a PC system instead of rb on the rooftop end with little effort but on the tower end I would need 2x150' (50m) of LMR to do that, and loose 2/3 my signal into resistance.

Also I live in Kansas. Here almost every day is 15-20mph winds in the afternoon. Storms every month have 60mph winds. Wind load and structural integrity is almost as important for reliability as signal.

The rooftop side will have more local interference because it is downtown.
What is the frequency range on that 28.5dbi dual polarized radiowave antenna? 5.1 to 5.8?

The Dual Nstreme link I have is less then a mile. One side is on a roof top but the other side is in a building. I have to shoot through 1'' mirrored and tinted glass at a 45*.
I use a via 533 on the roof top and an AMD643000+ in the building side.
The link does 65 send and 65 receive but only 90 on both.
The web link I posted shows the config.
Oh, and the antennas are all pac wireless panels. 19dbi in 2.4 and 24dbi in 5.x.
 
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dbostrom
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Wed Sep 06, 2006 5:22 pm


Also I live in Kansas. Here almost every day is 15-20mph winds in the afternoon. Storms every month have 60mph winds. Wind load and structural integrity is almost as important for reliability as signal.
Be sure to equip the dishes w/radomes. They're not only good for ice, they also do amazingly good things for windloading!
 
Connor9220
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Re: 200 MHz separation

Wed Sep 06, 2006 7:31 pm

If you don't understand why 200 MHz separation is neccessary then look on the hardware design of the WLAN cards or better look at professional ptp-microwave equipment. Thy have a separation up to 1080 MHz.
As someone stated, why can you co-locate a radio on multiple channels and not have this kind of problem.. Example, putting 2 2.4Ghz cards in in a RB532, run 1 on channel 1 the other on channel 6.. As for Professional ptp-microwave eq, I've seen a Tsunami 5ghz system using 5772 and 5872 Difference of only 100Mhz or so. It's a full duplex system.. Only thing I notice is that it's frequency's are determined by a band-pass combiner/splitter.. Which may make this possible. One other thing, WHY can't we see the CCQ for the links??? This would be VERY helpful it determining self interference issues
 
jober
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Tue Sep 12, 2006 5:43 am

Heres an antenna that looks good for singal antenna dual nstreme links.
http://www.mtiwe.com/data%5Cimages%5Cpr ... nvh_v2.pdf
 
miahac
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Sun Sep 17, 2006 3:42 am

Heres an antenna that looks good for singal antenna dual nstreme links.
http://www.mtiwe.com/data%5Cimages%5Cpr ... nvh_v2.pdf
Thanks for the link but I think I am going to need about 20dbi of headroom. I will try it for a couple shorter links I am looking at.
 
jober
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Sun Sep 17, 2006 4:56 am

Yeah, I did not really mean that it would be good for long links. SORRY!
I was just looking around and saw it so I posted it for future reference.
I'm thinking I may try it for my colo link to save some space. It's a short link.
Last edited by jober on Wed Mar 28, 2007 8:56 am, edited 1 time in total.
 
jo2jo
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Wed Mar 28, 2007 1:55 am

its a great antenna, but its expensive ~$300

super pass also has some 2.4 and 5ghz antennas in one
:beep :beep :beep
 
jo2jo
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Sun Apr 08, 2007 4:05 am

can anyone answer one of the original questions:

2. What is the best way to fail-over to one interface if the other fails, is it built in? or do you need to script?
:beep :beep :beep
 
bushy
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Sun Apr 08, 2007 6:52 pm

I use a simple script in case one of the pair of links fails. All it does it set the two remote cards in AP-bridge mode and the two near-side cards in station mode. The traffic will flow away over whichever link is still working. Tag on a script to send an email/sms message to your phone and that s it.
 
jo2jo
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Sun Apr 08, 2007 7:01 pm

beautiful....
i also assume that you are not using WDS since you switch to
ap-bridge and client mode. are you only passing layer 3 traffic?


what actually happens on NStreme 2 when one link fails? im assuming the entire link fails.

thanks
:beep :beep :beep
 
bushy
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Mon Apr 09, 2007 12:25 am

....
what actually happens on NStreme 2 when one link fails? im assuming the entire link fails.
thanks
I should have said thats what the script was for , in case one link fails and kills the Nstreme2 link .

Works like this :
If wlan1 and wlan2 are part of the Nstreme-dual interface.
Give wlan1 and wlan2 ip addresses as well as the Nstreme-dual.

Add a netwatch to trigger the script if it can't ping the nstreme-dual interface on the remote box.

The script does this : disables the Nstreme-dual interface, and changes the two cards from "nstreme dual slave " to "station"

On the remote end , add the same script but set the two cards in "ap-bridge" mode

Add on an email script to let you know the link is in trouble.
 
Skaught
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Re: Nstreme Dual Questions?

Tue Sep 11, 2007 6:28 am

Has anyone tried a single standard antenna with a combiner? I would be likely using the hyperlink one (seems to be the only one I have found) and put them in separate bands. One in 5.3 and the other up in 5.8.
 
steveloomis
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Re: Nstreme Dual Questions?

Tue Sep 11, 2007 6:25 pm

In response to the question about the 200 Mhz separation. The transmitted signal extends beyond the exact frequency in what is called sidebands and noise. These sidebands are much weaker than the main signal, however, in the presence of a very sensitive receiver, these sidebands can be "heard" if too close in frequency. Full Duplex means transmit and receive at the same time, not alternatively so the receiver is always listening and must have "space" between the transmit channel and receive channel. The radio cards we use do not have much in the way of selectivity (filtering) of adjacent side bands, so we must use as much channel spacing as possible for Full Duplex to work effectively.

On another note, horizontal and vertical polarity mean little up close to the antenna. Antennas are not perfect either. There are side lobes in addition to the main lobe, that extend in many directions and are easily received by a co-located receiver regardless of the polarity. Vertical spacing of the transmit and receive antennas should help provide isolation between the transmitter and receiver. Too many varibles to give anything beyond general guidelines. Trial and error works and is where this forum is valuable in sharing what works.

I hope this helps in understanding a little about Radio Frequency fundementals.

:D

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