Make the move from 2.4Ghz to 5Ghz?

[Griminal]

I'm currently using two M2 units for a backhaul and I'm wanting to move to 5Ghz.

The link below is a picture of the current stats for the M2 unit. (24dbi grids on each end). Do you think with these numbers moving to a M5 with comparable grids on either end would be feasible? The pictured signal is average. (59-65 depending on the weather.) Channel width, etc are all in the picture.

http://www.grimsplace.com/images/wireless/bulletm2hp_stats.jpg

[Dave-D]

I see no problem at all moving to 5.8GHz.

Why not upgrade to 30dBi grids at the
same time? Price is only slightly greater
($100 will get you a very nice grid)
and you'll gain 12dB 'in the bank'. Dave

[Griminal]

You mean like this one: http://www.wlanparts.com/product/K-GRID-003-06

Thanks for the advice. I didn't want to sink $400 on "trying".

[Dave-D]

Um--exactly like that one.

I use that exact antenna for a Bullet 5
12Km point-to-point llink, and I've had
excellent results. It's also far more
rugged than the $60 grids from a more
famous maker you see everywhere. Dave

[Dave-D]

Griminal, did you choose something? Dave

[Griminal]

No. I think I'm going to hold off until Spring.... but I will be making the move.

[mjnavapo]

I am in a similar case.

I have a link PTP approximate 5.8 km (3.6 miles) with two BulletM2 and two dishes of 22.5dbi grid.

I get a signal from -70dBm

I would like to switch to 5Ghz, specifically the Nanostation5 for convenience to include the antenna, but not if the integrated antenna was short for my link.

[Dave-D]

mjnavapo, your current link isn't
performing very well. Can you
define your signal path? How
high are the two radio locations
and what is in between?

Users get good results with NS5
at this distance with an open
path, but you may not have one.
My quick guess is you should have
at least 10dB more signal. Dave

[mjnavapo]

mjnavapo, your current link isn't
performing very well. Can you
define your signal path? How
high are the two radio locations
and what is in between?

Users get good results with NS5
at this distance with an open
path, but you may not have one.
My quick guess is you should have
at least 10dB more signal. Dave

Hello, my link is not very good.

Between AP1 and AP2 nothing. But just denlante of AP2 are several large trees and the antenna transmitted between them.

If I put the AP2 in a position near where the trees have not before, the signal improvement, commenting about those 10db.

The problem is I can not change the location of the antenna, and for it to be put on the tops of the trees need to put a turret high.

I have read that for these conditions (trees) is better dual polarization antenna, so thought of putting NSM5.

Besides convenience for the antenna installation to be integrated on-AP, and is visually more beautiful than my current antenna 76x76cm, which is very big and ugly.
And by switching to 5Ghz, which in my area this band is not used, to avoid interference from other wifis, and security, as with other 2.4 ghz wifis could not detect my network.

[Dave-D]

This doesn't look good to me. For
example, you have two 22dBi antennas,
and with the NS M5 you will have 15dBi
internal antennas. That's a total path
loss of 14dB, when you already have
a poor path.

Remember: the NS M5 does not have an
external antenna; they are not an option.

If you do choose to go to 5Ghz for the other
reasons you mention, I would use Bullet M5
with 30dBi grid antennas. That would be good
enough for a 20Km path or more in ordinary
conditions, but your conditions are bad.

If you want a dual-polarity MIMO setup, you
would need two Rocket M5 with dishes. That
will be very expensive and ugly. Dave

[mjnavapo]

I think it could solve my problem with the trees to improve the signal, so I'm going to think about putting NSM5.

Circles I've made a link, but not if the values I have are adequate for NSM5, I have looked at the spec sheet and put on the most dismal values for link quality.

Even so just give me a link,
think I can run?
This calculation is reliable?
I have values that are appropriate for the calculation?
will have a yield less than my current 2.4 GHz or link to be dual channel the anger NMS5 faster while having less signal?

Here you can see the results of the calculation:
http://img40.imageshack.us/img40/6811/enlace5ghz.jpg

Greetings.

[WHT]

I have a link PTP approximate 5.8 km (3.6 miles) with two BulletM2 and two dishes of 22.5dbi grid.

I get a signal from -70dBm

You have a problem somewhere. Like about 20 dB less than you should expect.

[Dave-D]

Mjnavapo, your calculations seem fine.
With a path loss of 122, gain for two
antennas of 28 and rf output of 21,
the result is about -74dBm at the
receiver. This is marginal.

I would suggest you use better antennas.
Use two good cast aluminum 30dBi grids
at under $100 each. That will give you
another 32dBi, for -42dBi at the receiver.

That will give you far more than you
need--but the price is right. Note the
NS M5 has no external antenna port,
so you'll need to use Bullet M5 with
1X1 MIMO. Does this work? Dave

[WHT]

mjnavapo...

If you are running at MCS-7, I'll use 22 dBm TX TPO and -74 dBm RX levels for a path calculation, using 22.5 dBi grids at both ends for a 3.6 mile shot.

You should be getting an RX level of around 50 dBm. But you said you have trees in the way, so that will reduce the path by perhaps 10 or 20 dBm. This you already confirmed by getting a much better signal without the trees in the way.

So lets look at your idea using two Nanostation M2 radios (forget about 5.8 if you have trees in the path). The Nano has an internal 10 dBi antenna, so the -50 dBm number I mentioned above would now be only -75 dBm. Which is all right IF you had no trees in the way.

Edited for correction and clarification above: -75 would be marginal at MCS-7, but sufficient for MCS-1.

If you think the dual-polarity of the Nano M2 might help on the premise you are loosing a lot of VPOL signal and the HPOL might get through. So try this. Rotate your existing 22 dBi antennas to an HPOL position and see if that helps you. If it doesn't, then the Nano M2 won't help you either.

[Dave-D]

WHT, maybe I'm missing the obvious,
but I see no NanoStation M2 on the
Ubiquiti product list.

I had been discussing the M5. Dave

[WHT]

The Nano M5 would not be a good choice if he has trees in the way, that's why I mentioned the Nano M2.

He can find it at:
http://store.microcom.us/nsm2.html
http://store.wisp-router.com/itemdesc.asp?ic=NSM2&eq=&Tp=

[gullisig]

Here you can see the results of the calculation:
http://img40.imageshack.us/img40/6811/enlace5ghz.jpg

Greetings.


What program did you use for the calculation?

[Dave-D]

Both store links say 'January 2010'.
Ubiquiti doesn't even list NS-M2 on
their Website yet. Patience is a virtue....

Assuming his point about path loss
about 10dB due to trees at 2.4, and
at least 25dB fade margin at 5 using
30dBm grids, do you feel he should
wait for NS-M2?

Assuming the NS-M2 built-in antennas
will have gain similar to the NS2 [10dBm],
he will have even poorer signal than now. Dave

[mjnavapo]

What program did you use for the calculation?

http://www.ligowave.com/linkcalc/main.html

[Dave-D]

Mjnavapo, when I said your calculations
'look fine', I meant that the theory looks
good. I should have mentioned that you
didn't include any loss for the trees.

If you put in a 10dB loss for the trees
as you discovered by experiement, that
is OK for 2.4, but at 5 it would be even
higher. I'll do a wild guess of 15dB.

Try adding 15dB or more to your loss,
and see what that does. I think those
30dBi grids start to look good! Dave

[mjnavapo]

This is currently my link with Bullet M2

http://img21.imageshack.us/img21/8560/enlace24.jpg

I guess the height that the application will show soil, so there will have to add the height of the trees.
AP2 front of this all covered with trees of 3 to 4 meters (10/13ft) high, throughout the mountain that is seen in the image.

I did the test change the polarity and although I do not remember the exact results, if confirmed as horizontal polarization works a little better than vertical polarization.

Assuming that the vision was optimal, without trees in between, the NS5M are sufficient to cover a bond of about 3.5 miles to the maximum rencimiento, or even be the perfect visibility is too far for a NSM5?

[WHT]

Try adding 15dB or more to your loss,
and see what that does. I think those
30dBi grids start to look good!By what process do you think adding more gain would help? The process of how trees disrupt a wireless signal is not by attenuation.

[Dave-D]

He says that moving the radio so
it avoids the trees increased his
2.4 signal by 10dB (if I read him
correctly). So by experiment,
it appears the trees attenuated
his signal by 10dB. Bad logic? Dave

[Dave-D]

Mjnavapo, the path loss of about 122
that your calculation application shows
is about right for an open path. It does
not include terrrain loss, such as trees.

With a perfect path, the NS M5 should
be good for a 5Km path. You can easily
do the calculation yourself. NS M5 has
internal antennas of about 15dBm gain.
Maximum rf is 27dBi; I would use 24. Dave

[WHT]

The trees are not significantly attenuating the signal, where attenuation would be the partial conversion of the radio wave to heat by an intermediate media, resulting in a decrease signal arriving at the receiving point.

The reduce signal at the receiving point is caused by tree induced destructive interference. Texas A&M published a paper explaining the process.

[mjnavapo]

In this photo you can see my link:

http://img248.imageshack.us/img248/4075/enlacewifi.jpg

The photo is from tomanda zoom position AP2.

AP2 front of two pine trees about 40 meters. The AP2 broadcasts in a hole in between the two pines.

Until about 700 meters from AP2 is trees (olives), about 4 meters of the lowest emission line of wifi.

As shown in the photo, the AP1 it looks good from the AP2.

[WHT]

That's the "keyhole" effect. Even though you might even indeed see the other antenna, the Fresnel interference is causing a reduction in the received signal.

[Dave-D]

'Keyhole effect', 'destructive interference'--
whatever. The question is whether higher
gain in the path will ovecome these effects,
which combine to decrease signal.

So what is your conclusion, WHT? Dave

[kilos]

Are you able to raise the local AP by a few meters to test the signal ?

[WHT]

Destructive interference would also be increased with higher gain.

For the same reason receiver amplifiers aren't effective. They increase the targeted received signal as well as the ambient noise, so the net gain a zero.

[Dave-D]

I would guess 'destructive interference'
would have the same percentage effect
on the signal, and would only go up in
that proportion to the power increase.

In any case, beside the obvious (moving
the radio/antenna), where does this
leave poor mjnavapo--with no NS M2
in sight? Dave

[WHT]

He needs a better path. Raise one of the antennas or invest in a chain saw.

[Dave-D]

So, mjnavapo, back to what I said in
your first response--post #8. You
have a poor path. I still believe you
can 'power through' it using those
two big grids. But I can't prove it.

Good luck with this! Hope your
neighbors don't complain about
the missing trees in the morning. Dave

[mjnavapo]

I made a new test:

Behind the house is the AP2 is a small hill of about 15m higher than the house. From this point forward no trees (are lower), so that the vision is perfect.

I could not try with my antenna 22.5 dBi but I tried with a similar 24dBi.

MCS7 mode:

No network traffic: AP1 60dBm / AP2 50dBm
With maximum traffic (35Mbps transfer constant): AP1 60db / AP2 60dBm

Why not AP2 increases traffic signal?
Why have not always 50dBm at both ends which is the theoretical signal if the test conditions are good?

[mjnavapo]

He returned for another test like the one above.

I put the antenna of AP2 in an area where trees have not before, the antenna is again a 24dBi antenna instead of my 22.5 dbi.

No use of the network:
In a sign of AP1 have 58dbm
In a sign of AP2 have 50/52dbm

With use of the network, maximum transfer rate:
In a sign of AP1 have 58dbm. CCQ 95-100%
In AP2 have 59dbm signal. CCQ 75-90%

Do these values are appropriate for a 3.5-mile link BulletM2 mode MCS7?
AP1 Why is always the same sign, both without traffic and with traffic on the network?
AP2 Why have different signal when there is traffic when there is traffic on the network?
Why the CCQ of AP1 is high and the AP2 is lower and variable?

Greetings.