This simple power meter allows you to see the output power of a card.. it can help you check cables, cards, and antennas.
Here is some startling info I found out.
I tested 5 SR5s and 5 Senao 200mW prism cards
Senoa Prism gave 200mW/24db output everytime excpet once. 1 card put 17db.. that card is now set aside as bad
SR5 …100mW!!! max db is 20 and that is after setting tx-power to all fixed rates and then setting 30db!!!
this happens on all SR5!!!
hello?? there is something wrong here.
I use mini-pci board with routerboard 14 4-min-pci -pci card. I read the specs and it says max power for each slot is 2.5watts.
We looked up the specs on the SR5 and did the math. You need 5.25 watts for full power. So I got got out my routerboard11 1mini-pci -pci card and it says it can do 5watts.
guess what?
only 100mw on those as well. I tested on other hardware platforms as well and still on 100mw of power. I would name the other hardware, but I dont want my post deleted.
I think there is a major problem here. I hope someone else can buy the power meter and do the same tests.
I think we really need to bang on this hard, I am looking for some kind of hardware that can support the full 400mw of the SR5.
I talked to my vendor who resells Sr5 and he said Ubiquity told them when they announced the cards that nobdy could support the power and that the motherboard companies would have to catch up.
The biggest problem I see is that I can get 200mw out of the prism card, but only 100mw out of the SR5. I would be happy for now for 200mw out of the SR5.
other than that the power meter is great for finding bad cables and pigtails and such. Since I have bought it and gone out to all my nodes, I have found and replaced ~10 cables. Some had much more loss than others.. some lost 10db!. But now that I can sit at the bench and test cables, I was able to replace the cables with known good ones. This has increased my performance alot. I can now get 10megs 5 hops out
At what transmit rate did you test the SR5 radio at? You are aware that the transmit rate at 54Mbps is rated at 21dB +/-1 right? You might want to check with the spec sheet for this card and test each transmit rate (although power for 6-24Mb should be the same). Also verify that the card power settings are running as they should be.
I think Mikrotik would have to comment on if testing a beacon accurately reports the transmit rate power - I simply don’t know. But, if there is no link for the radio to negotiate a transmit rate, it seems like your test may not be accurate…can anyone confirm this?
Also, setting your card to 30dB…this is 1 Watt. The maximum that card supports is 26dB. Perhaps this is causing some problems too?
With the prism I get 24db in the same test. Also when I set it to 30db.. I first started at 14db and slowerly worked my way up. It was accurate to 20db..then as I raised the db above 20, the power meter never went above 100mW/20db
Another point is the power meter is designed to test the card, and it has a terminator on the other side for accurate measurments. So the meter is not supposed to be used when it is connected to a network.
I have set the power to default, and then I change it to all-fixed-rates.. ALso the power meter works in 5.8 , 5.3, and 2.4. I always change the frequency to 5785 before I start the test.
When it is default mode. It puts out 17db.
the routerboard14 states in the spec sheet that it on allows 2.5watts per card.
the routerboard11 states in the spec sheet that it allows 5 watts
The SR5 need 5.25 watts to run full power
when I put in a 2.4 prism card.. it runs at 24db /200mw or full power
this is in default mode
when I put it the SR5 in default mode. it runs at 17db/65mw
when I change the power mode to all-fixed-rates and then change the db. I can get it up to 20db/100mW
When I have the SR5 set as a station, it shows advanced-status in winbox. Which shows the db output range. it looks like this
6Mbps = 17dbm
9Mbps = 17dbm
12Mbps = 17dbm
18Mbps = 17dbm
24Mbps = 17dbm
36Mbps = 15dbm
48Mbps = 13dbm
54Mbps = 11dbm
here is another SR5 in the field
6Mbps = 19dbm
9Mbps = 19dbm
12Mbps = 19dbm
18Mbps = 19dbm
24Mbps = 19dbm
36Mbps = 15dbm
48Mbps = 14dbm
54Mbps = 13dbm
and here is a CM9 in the field
6Mbps = 12dbm
9Mbps = 12dbm
12Mbps = 12dbm
18Mbps = 12dbm
24Mbps = 12dbm
36Mbps = 10dbm
48Mbps = 8dbm
54Mbps = 7dbm
Now after testing lots of card I see that some card simply do not put out the correct amount of power.
I have seen a few prisms that put out 17db.. but I have yet to see any SR5 put out more the 20db.
I have ordered a new intel mb with 4mini-pci slots that states it has 18watts of shared power for the mini-pci..I should be getting that next week. Maybe that will change it ..
but the big fact remains that according to the Microtik specs showing 2.5 watts per mini-pci card on the routerbaord14, I think it is impossible to get full power, but what I do want is at least 200mw.. which I can see on the prism, so I know there is enough power for that.
The 802.11a specification uses OFDM modulation but also defines many other aspects of the signal. When an 802.11a device is not transmitting data, it will transmit short bursts (48uSec) of energy. These OFDM bursts contain four distinct regions resulting in a power envelope that is not constant with time. The bursts’ output power peak-to-average can vary as much as 8dB across the burst. The PM-2458 is designed to measure peak power, so what a user sees on the display of the PM-2458 is a power measurement that is quite a bit higher than the radio manufacturer’s power output specification (average power), as the meter samples these varying peaks. The meter will not display an average or constant power reading.
Interesting. Have you tried this test with a fresh install where the SR5 is the only card the OS has “seen”? I have run into some random problems in the past with radios after swapping out different cards. Any chance you have access to a spectrum analyzer for that band?
FWIW, We’re still using CM9 radios as we have seen too many issues posted about the SR2/SR5…they work great for some people, and not so well for others. We’re still excited about the SR9 (if it ever comes out) as it will make some of our deployments a lot easier (and cheaper) but I fear these same issues will hinder their success due to the power draw issues
We did test a couple of SR5 with a spectrum analyser and did not get any reading above 21dB. The radios was transmitting at 6mbps and we did set the radio in aling mode so it was always transmitting. The cards was installed in a wrap and a RB532. Both was pumping out the same amount of power.
These numbers corroborates reading I made on some p2p link I have made with SR5.
on what platform do you get full power?
It clearly states on the spec sheet that the routerboard 11/14/18 cant support the power needed to run the SR5 at full power. I am looking on http://www.routerboard.com and I cant seem to find any spec that show the maximum watts the mini-pci slots can deliver for the RB532.
The only way I know the watt usage on the routerboard11/14/18 is that I just bought 3 from wisp-router and it came with a spec sheet. I also bought a routerboard532, that has not arrived, but I am hoping it will also give this detail.
Maybe since Mikrotik built the RB532 they could share the spec here and not make me wait for mine to arrive.
I did tests in the 5.8 frequency, just like you said too. I dont even bother using the any other frequency.
Frequencies used for testing
5745
5785
5805
5825
and I was just looking for a spec that shows the SR5 using less power in other bands.. I cant find one, can you perhaps post a link please?
So I received a Routerboard 532 yesterday and tested all my new SR5s on it and even though inside the winbox, it says it is 26db, the power meter on shows 21db.. and it jumps around alot.. from 20.5 to 21.8.
the prism cards on the other hand stay steady at 24db.
If I set the power to default on the SR5s it show 17db and remains steady at the level.
SR5 tests were done at 5805 and prism test were all done at 2.412
I am still awaiting my new 4-minipic intel motherboards that say they share 18watts among the mini-pci slots.
Also I can still find no specs on the power output of the mini-pci slots for the RB532.. anybody have that info?
