How do you know when your wireless cards are putting out max power?

In the wireless screen there is a field "Antani Gain" what should go here? the gain of your antani that is connected to the card?

On the window "TXpower" there are four choices default, all rates fixed, card rates, and manual. What should be selected here? When I go to manual I show 17dBm

If these above items a specfic for a particular wireless radio were do you get the settings that you should be using?

-------------------------
I have a 1/2 mile 5.8ghz link that has just crap signal at -85 to -90 and won't run more than 6meg. I have tried everything from replacing antani's, cables, connectors. Clear line of site from the top of our building to the tower. We were using a direcinal 22db grid to a 10db omni, switched the 10db omni for a 14db panel (5.8) and went from -85 to -79. Then switched the panel to a sectored 16dbi (120 degree) and it's stable at -79. (short 6 foot cables on both sides. Both units are the rb230 units, ntream off, no turbo mode at 5825 mhz. (with antani's that match that fequency)

---------------------------
I had planned on running 802.11A links to each of my wireless relay sites (six of them). And then 802.11b down to the customers. If I setup wds on the 802.11b links at all six relays do I still have a need for the 802.11A links?

--------------------------

Can Prisim pmcia cards run wds? I tried turning one of mine on for a test and gave me an error?

---------------------------
IF you turn wds on can my clients connect as they do now? I use the Linksys GS routers with sevasoft software loaded and autenticate via ppoe?



Regards,
Michael

Hi Michael

You are clearly having some kind of link loss that you shouldn't have according to your description.... but let's start with some replies to your questions.

Antenna gain is used by the router OS to calculate the maximum "legal" output power, what it does is to;
- take the country setting (which you may or may not have set) to find the maximum allowable output power (usually 30dBm)
- subtract the antenna gain you have set (which should be set to what your antenna specification says)
- and then automatically adjust the output power of the card to get the maximum legal output from the antenna

Exampel
Country = Sweden -> maximum legal output = 30dBm
Antenna gain = 22dBi
Maximum output from card -> 30 - 22 = 8dBm!!!

However you also need to include contacts, cables, pigtails etc in the "antenna gain" value... so from your specs you would get something like this for each antenna gain
Your building;
22 dBi antenna - 6 feet cable (not specified what type so I'll go with RG223) - pigtail (not specified either so Orinoco it is) - connectors if more then absolutely needed (antenna to cable, cable to box, box to card)

22 - 3.16 - 0.7 = 18.14 in real antenna gain on your building, that would give you a maximum legal output limit from the card of 11.86dBm!

Link site 16 - 3.16 - 0.7 = 12.14 antenna gain - > 17.86 dBm legal output limit on power from card

So if you set the country/antenna gain values you might get lower output then you expected

Now for what you should be able to get;
Let's say that we have 30dBm out from each site (just to be legal).. and a 1/2 mile line of sight (do you really have LOS? LOS is not just line of sight... you need a clear fresnel zone, that's about 21 feet radius around the line!!!)

Some numbers, almost legal numbers to
pOut = 12 dBm (power from card)
Ltx = 4 dB (link loss on transmit side, cable + pigtail)
Gtx = 22 dB (antenna gain transmit side)
FSPL = 105 dB (link loss with clear fresnel zone)
Grx = 16 dB (antenna gain receiver side)
Lrx = 4 dB (link loss receiver side)
Formula is pOut - Ltx + Gtx - FSPL + Grx - Lrx = Pin
Pin on link site should be 12 - 4 + 22 - 105 + 16 - 4 = -63dBm!
And the other way 18 - 4 + 16 - 105 + 22 - 4 = -57dBm (better antenna on receiving side)

So... there is something stealing your umph - bad cabling / bad connectors / not clear LOS etc.....

What kind of cabling (brand) do you have? Do you have any sharp corners on the cable?

I have a 3.5km link that runs on -70dBm (2 RIC522 integrated antenna/router) with legal settings so you should have better then -79!

Hope this was clear and readable, don't hesitate to ask if I wasn't clear

/Jörgen

http://www.smyth.net/tower.jpg

Looking at this picture you will see our tower on the moutain (large hill) over looking the town.

The cable runs to the antani's are 25 ft lmr-400. On the center poll is a 16db omni using 2.4 ghz to customers. On the right poll is a 8db 5.8 mhz omni.

We have changed the 8db omni to a higher quality 10db omni with no noticable change.

Changed the 10db omni to a directonal panel (which you can see mounted at the base of the 2.4ghz center poll.

Changed from the directional panel to a 16dbi 5.8gh sectored antani that is 120 degree wide 8 degree horzontal and horzontal polarzation yesterday.

Changed the polorzation on our building from vertical to horzontal. This antani is a 22 db grid antani.

http://www.smyth.net/tower_box.jpg

picture of the inside of the box
---------------------------------------
http://www.smyth.net/office.jpg

picture of the old roof installation for referance to the tower on the mountain.

--------------------------------------
http://www.smyth.net/office1.jpg

Closer to what is actually isntalled on the roof now. But I have removed the 5.2ghz dish on the right and moved the 5.8ghz to the right poll.
--------------------------------------

We had a nice 5.2ghz link using those two identical dish antani that you see in the above office.jpg picture but when we put up a taller tower on guy wires the dish was too large, to heavy, and the wind would cause the tower to move around alot. So we moved to 5.8 because I could use more power and thought I could get a longer distance link than the 5.2.

My next relay is to be from the tower over to fm radio station tower which is less than 5 miles and is almost shooting right back over my office roof (but about 10 degress off). My office can not see the fm tower but can from the relay tower pictured.

I havn't installed on the fm tower yet because I can't even get my relay link to work.

The 2.4ghz link however seems to do excelent execept for one spot in town (that has clear line of site but there must be some other interfearance) and it is a very small area of about 4 bussiness store wide.

---------------------

Thank you ver much for the above information in your reply, it is very imformative!

Reagards,
Michael

Wow, with line of site that clear, and distance that short, you should have NO problem making that run at 54mbps.

The only thing I can think of is maybe some of those close by roofs are causing singal refraction/reflection problems. Perhaps taking your patch on that side up another five feet might help significantly.

It's difficult to tell, but it also looks like you don't have any up-tilt on your antennas - which is going to DEFINATELY be necessary (and downtilt on the other side too!).

Hi again

I have to agree with Nick here... that link should perform very well!

One stupid question, how about polarization? Have you checked so that all antennas are aligned the same way... and double-checked by rotating one? Bad polarization can cause a loss of 20-30dB

Also, what's the box that the cable seems to run through on the hill? Seems to be some kind of connector/adapter between the pigtail and the box..

/Jörgen

Hi again Michael

I see some different information in in your posts.. you started by stating that you had 6 feet low-loss cable and now you say that you have 25 feet lmr-400?

Could you check that you haven't accidentally gotten the LMR-400-75? That could explain your bad numbers!

Also, a "detailed" spec of what you have in each transmision line would be great.

As an example;
- card (Prims)
- pigtail (Orinoco mmc - N-male)
- adapter (50 Ohms N-female - N-female)
- 3 ft LMR-400 (50Ohms N-Male - N-Male)
- bulk-head adapter (50 Ohms N-female - N-female)
- 25 ft LMR-400 (50Ohms N-Male - N-Male)
- antenna 22dB (brand xxx)

With such a spec it's easier to do the proper math... the example above would cost you;
- card (Prims)
1.3dB - pigtail (Orinoco mmc - N-male)
2 * 0.5dB - adapter (50 Ohms N-female - N-female)
0.33dB - 3 ft LMR-400 (50Ohms N-Male - N-Male)
2 * 0.5dB - bulk-head adapter (50 Ohms N-female - N-female)
2.6dB - 25 ft LMR-400 (50Ohms N-Male - N-Male)
0.5dB (connector on antenna)
no cost, just gain - antenna 22dB (brand xxx)
So.. a loss of about 7dB just in this line!

and yes, I KNOW that these are grossly oversimplified numbers.. so all of you reading, please don't flame me. I'll do beter when I get Michaels specs

Also, please check that you do not have any 75Ohm connectors, bulkhead adapters etc.... that would kill your link! Assuming of course that you are using 50Ohm gear?

/Jörgen

Ok :)

On our building I have an rb230 with a prisim 2.4ghz card and an ar5211 5.8ghz card. The 2.4ghz is the omni on the right poll in the picture. The 22dbi grid antani for for freq 5825 which is showed under the 2.4ghz omni in the picture has been moved to the right poll. The radio is feed by a power over ethernet adapater and the radio is connected to both antani's with lmr-400 10 ft lenth cables. No other connectors other than the pigtails from the card to the outside of the box.

On the tower is an rb230 with prisim 2.4ghz card and an ar5211 as well. The 2.4ghz prisim card is set for 30mw output and feeds into a 1 watt amp into a 12dbi omni with 3 degree downtillt. The ar5211 is hooked directly to a 22dbi grid antani for freq 5825. The Omni is feed with a 25 foot lmr-400 and the 22dbi grid antani is feed with a 10 foot cable.

Both grids have been changed from vertical to horizontal yesterday. I get a -79 strenth at this time. The link speed is 6meg using normal 5ghz setting (non-turbo, or netstream). If I push the connection speed up it just jumps all around up to about 36meg for a few seconds but normally just stays at 6meg. If you try to lock the speed at anything higher than 6 the connection drops.

tx/rx ccq is 34/32
ack is 33
tx mode is set to manual with 17 in each of the fields.

-----------------
I am on the way to the tower at this time to replace the rb230 with an rb500 using the 400mw sr card for 5ghz.

I will post the results later this evening with some new pictures.

I also over nighted a new full set of pigtails for this installation as well.
-----------------

Thanks!
Michael

Hi again

Looking forward to hearing the results... problems like this is fun when you're not the one having to fix them!

If I where to do your link, knowing what I do from the few installations I have done AND if I was sure I would not need NStreme2 I would go with the integrated rb500/22dB antenna (RIC/522) on both sides. Of course that means that I would have to place a switch and another unit for the customers at the tower but I would still do it this way.

That's what I am using on my rock-solid 3.5km link (upgraded to SR5 cards by Mikrotik before delivery) and people are right when they say that big ears are more important then a big mouth

That combo gives me an excellent sensitivity on the rx (the SR5 are MUCH better at listening then the standard cards!) and I do not have any loss except for the pigtail so they can hear almost anything.. -94@6Mb compared to -88@6Mb for the CM9. That's a cool extra 6dB margin without any fancy antennas!!

Counting in a few feet cable, some connectors and such I would loose another 2-6dB compared to a standard setup with a CM9 or R52 card and external antenna.

/Jörgen

Had some nice weather so I was busy doing some tests today.

I reconfigured the 5.8ghz antani's. At the office 22dbi grid vertical polorized. At the tower a 10dbi omni. Both sides using AR5211 cards (65 mw I belive). The signal strenth became a solid -79.

After reading about power amp's in a different thread I decided to remove my 802.11b (yes defferent freq) from the tower box and unplug it. The 802.11a signal strenth became a solid -74.

I was very excited to see that singal change because it gives me an idea of what is going on.

Now for the bad news. Removing my amp my 802.11b clients droped signficant.

from - to
-73 to -93
-75 to -95
-76 to -89
-70 to -91
-62 to -82
-65 to -84
-73 to -92.

The cable run from the radio to the omni is a 25 foot lmr-400 cable.

I took all new pictures of both sites and will post soon.

Some additional information
the 5ghz 5825 shows a ccq of 33% and ack of 33
below is the card setups:


0 R name="wlan1" mtu=1500 mac-address=00:01:24:70:33:25 arp=enabled disable-running-check=no
interface-type=Atheros AR5211 radio-name="000124703325" mode=ap-bridge ssid="SmythNet" area=""
frequency-mode=manual-txpower country=united states antenna-gain=0 frequency=5825 band=5ghz
scan-list=default rate-set=configured supported-rates-b=""
supported-rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps basic-rates-b=""
basic-rates-a/g=6Mbps max-station-count=10 ack-timeout=dynamic tx-power-mode=default
noise-floor-threshold=default periodic-calibration=default periodic-calibration-interval=60
burst-time=disabled dfs-mode=none antenna-mode=ant-a wds-mode=disabled wds-default-bridge=none
wds-default-cost=100 wds-cost-range=50-150 wds-ignore-ssid=no update-stats-interval=disabled
default-authentication=yes default-forwarding=yes default-ap-tx-limit=0 default-client-tx-limit=0
hide-ssid=no security-profile=backbone disconnect-timeout=3s on-fail-retry-time=100ms
preamble-mode=both compression=no allow-sharedkey=no

1 R name="prism1" mtu=1500 mac-address=00:02:6F:01:D2:8F arp=enabled disable-running-check=no
interface-type=Prism prism-cardtype=200mW radio-name="00026F01D28F" mode=ap-bridge ssid="Inet02"
area="" frequency-mode=manual-txpower country=united states antenna-gain=0 frequency=2437 band=2.4ghz-b
scan-list=default rate-set=configured supported-rates-b=1Mbps,2Mbps basic-rates-b=1Mbps
max-station-count=30 tx-power-mode=default periodic-calibration=default
periodic-calibration-interval=60 dfs-mode=none antenna-mode=ant-a wds-mode=disabled
wds-default-bridge=none wds-default-cost=100 wds-cost-range=50-150 wds-ignore-ssid=no
update-stats-interval=disabled default-authentication=yes default-forwarding=yes default-ap-tx-limit=0
default-client-tx-limit=0 hide-ssid=no security-profile=default disconnect-timeout=3s
on-fail-retry-time=100ms compression=no allow-sharedkey=no

Ok this is the current set of pictures (directory browsing is turned on so you can see the pictures)

http://www.smyth.net/wireless/

It really sounds like there is a problem with your cable, pigtail, antenna, or jumper. Have you tried replacing all of these items one at a time. Are you sure you don't have water in one of your connectors, or corrosion?

I need to re-ask/restate a few questions:

1) How do I know that my cards are putting max power out? Prisim cards have a selector of 30mw, 100mw and 200mw. But the ar cards do not.

2) If I turn on WDS on my routers can my clients connect normaly or do they need to change the way they connect? (currently using sevasoft ios on linksys GS routers) And I authenticate the users via ppoe/radius.

3) When using a 22 dbi grid antani to a vertical omni... I know about turning the center element vertical (the diagram shows me this). but should I also turn the grid as well?

Ah yes.... I forgot about those,
#1, Easiest way to see/set the tx-power would be to use winbox, it's all there in the interface (interfaces / wireless / tx-power). Granted the CLI is the "proper" way for us old timers to go but still there is a few things to be said for GUIs to

Otherwise you'll have to set the card to tx-power-mode=manual-table and then go to the submenu "manual-tx-power-table" and define what you want it to use, this is a slightly hotter then legal setting
/ interface wireless manual-tx-power-table
set wlan1 manual-tx-powers=1Mbps:24,2Mbps:24,5.5Mbps:24,11Mbps:24,6Mbps:24,9Mbps:24,12Mbps:24,18Mbps:24,24Mbps:24,36Mbps:17,48Mbps:17,54Mbps:17

#2, Never used WDS, can't say anything about it. I use WiFi only for static links between locations and then copper cable to workstations

#3, Uhmm..... good question, on a parabolic antenna you would just rotate the head but on a grid???? Since the reflector isn't round I (just my personal though on how I would have done it) would have rotated the whole antenna to get the polarization correct... just like with a flat-panel antenna. Anyone here that knows for sure how this works?

/Jörgen

How do you know what settings to use for each type of card?

powers=1Mbps:24,2Mbps:24,5.5Mbps:24,11Mbps:24,6Mbps:24,9Mbps:24,12Mbps:24,18Mbps:24,24Mbps:24,36Mbps:17,48Mbps:17,54Mbps:17

is for which of the radio cards?

Hi again

Well, basically the command should state which card you are tampering with
set wlan1 manual-tx-powers=1Mbps:24,2Mbps:24,.... would be the card wlan1
and set wlan2 manual-tx-powers=1Mbps:24,2Mbps:24,.. would be the card wlan 2 etc

I guess your browser did a line break on the config line, here it is in code view, this is supposed to be on one line Hope this helps

/Jörgen

Actually Joe, that wasn't quite the answer I was looking for. Let say I have an sr5 card. How do I know what the max numbers I could use use for each setting?

-----------------------
Still don't know If I can turn on wds on the access point and my normal linksys customers will still connect as normal. They just connect to the ssid, and authenticate over pppoe.

------------------------
I havn't tested this yet myself because the unit that I have in the tower right now is a prisim card that doesn't seem to work with wds. I get an error stating it dosn't work when I try to switch it.

------------------------
I want to program this new unit I have with sr5/sr2 cards so that I can do wds on the 2.4ghz band but at the moment I cant get the unit to connect at 5ghz to the backbone link.

Which is what most of this topic has all been about.

I am down to two theroies.. my signal can't reach me because i have a 10dbi 5ghz omni on the tower and I am below the signal. Or 5ghz wont shoot through single pain (no uv filtering) glass.

-Michael

a couple of answers to your q's:

regarding the grid antenna polarisation - you have to turn the whole antenna. The polarisation marks go across the narow part of the grid, so that when the 'wings' are spread outward, it's vertically polarised...

regarding WDS on an AP - no, your clients won't have to change the way the connect... you can run both, but I'm not sure about using PPPoE & WDS on the same interface...

--edit--

Also, if your omni is high up, and the grid low down, it is as you think it is - the omni has an uptilt (about 15 deg, I think) in the polar pattern... you need a grid at the top pointing down to your office link...

Hi Michael

Seems I misunderstood your question, I thought you asked HOW to set the tx-power... the values of max tx-power can easily be found if you look at the specifications for each card, you might be able to tweak the card above those values but you usually end up with horrible side-frequencies that will bring FCC down on you if they find out

SR5
http://www.mikrotik.com/Documentation/sr5_datasheet.pdf
CM9
http://www.mikrotik.com/Documentation/5g_agp3.pdf
R52
http://www.mikrotik.com/Documentation/R52bA.pdf

/Jörgen

Yes, that is the information I was looking for. I do not want to over-power or push the limits on anything but I did want to know what would be the limits as to what you could enter in the tx levels.
-----------

Hey Bruno, I mean Normis :twisted:

Does ppoe continue to work over wds network?

Thanks
-Michael

Hi Michael

Any luck on this? Have you gotten the link up to a decent signal level?

/Jörgen