I have an RB200 with a 4 CM9 cards in it currently. I would like to replace 2 of the 4 cards with SR5’s. Can the RB200’s PCI slot support that much current draw? I’m using a 12V DC power supply plugged in directly (no POE).
The RB14 cannot supply enough current to power the four cards. I had this situation myself and support confirmed it will not work.
So when using SR5’s I need to use a single-PCI to miniPCI adapter, or is it only in the RB200’s PCI slot it can’t do it?
The RB200 has the ability to make 15W for the entire board. The SR5 needs 4-5W avg and more for it’s max. Whatever you do, you will be on the edge of the limits. The RB14 LDO (power regulator changing 5V to 3.3V) can put out 4.95W and there is one for two mpci connectors (two LDOs on the RB14 board for a total for four mpci connectors). The SR5 is out of the mpci standard, so anything you do with it will be risky unless the platform was designed to support it.
John
Or you could put the SRs into only four or five of the eight slots on a RB18… 
Or you could use only one SR radio per regulator, and then pair it with a low-powered radio, so that you have a low-powered radio and an SR radio on each regulator, which would be 5 watts or less per pair if you didn’t turn the radios up too high… Also note that many switching and linear regulators can supply more current than they are rated for if they are kept cooled to temperatures below that of the manufacturers maximum rating, although I doubt if Mikrotik would recommend that… 
I would also think that you could pair a set of NStreme2 radios between one regulator, since one of the radios would only be receiving most of the time, significantly reducing it’s overall current draw…
Hitek
PS. I also notice that a company called SparkLAN is offering a high-powered Atheros based a/b/g Mini-PCI card, among other interesting products…
Sparklan website is saying +15dBm for “high power” card @ 54Mbps 802.11a/g…
19dBm for 802.11b.
Interesting, as the Ubiquity cards are either 2.4 OR 5GHz. This is still combined.
Also, it’s a type IIIB card, need 5V power. Not sure if all embedded router boards can do that.
Regards
Ummm… I think that the “III” in “Mini-PCI IIIb” means that the card uses the 124 pin connector, as opposed to the 100 pin connector of the older cards, and the “b” or “a” refers to the dimensions of the circuit board…
The CM-9 is a “IIIb” board…
Hitek
Thanks for that HiTek -
On the datasheet it says the PA is on the 5V rail for ‘a’ mode -
Might not work with everyone’s boards.
Regards
Oh, yea… I did see that… I think it meant that the 5 Volts is for the amplifier when using 802.11a mode. It’s still the same chipset, so a large portion of the current draw should already have been compensated for in the requirements of the built-in amplifer. In other words, if a separate amplifer circuit(still not sure there actually is one) is producing the the radio’s power output, then the chipset’s built in amplifer would no longer have to work as hard, drawing much less current than it normally would, offsetting the additional current required by the additional amplifier. Of course, as you say, if the additional current draw is now on the 5 Volt line, it could cause problems with some boards of limited current supplying capacity…
Hitek
Yup I agree, and don’t know what proportion of a “high power” WiFi card is for the power amp (TX) vs. the rest of the chipset.
I have asked MT support to confirm compatibility (no response yet) and will order some up for testing if they are going to be recognised in MT.
Regards
UniKyrn, I don’t get why you are bashing the wraps so much WRT to these cards…you haven’t even tried one. According to the whitepaper at ubnt.com, the wraps are listed in their compatibility list.
It’ the Sparklan part that says 5V on datasheet - not SR5
If I read the specks on the SR5 correctly worst case is 4.65 Watts. I assume that I can use the RB11 with a SR5 since it is showing 5 Watt max. Is this correct? After reading Tulle’s comment on the RB14 I am thinking maybe I can use a RB14 with 2 SR5 cards, as long as I only put 1 card per LDO and not use the other card slot? Is this correct? Is it possiable to change out the regulator to a higher power chip to get the wattage higher so that I can use the RB14’s that I currently have with the SR5’s?
Thanks
Mike
We may offer a RB14 with a higher power LDO. But, the 50% of the power used by the cards will be wasted by the LDO to make the 3.3V. So the efficiency is ~66%. The PCI specs have 20W as the required 5V for the PC PCI bus. So, with four cards running at full speed, you will use 30W. Also, the RB15 is not such a big board to dissipate 30W of heat. As I said, you are on the edge or over it. If your radios do not use the max power (which is usually the case – you are not transmitting all the time, you need to receive, and there are many other reasons for not transmitting), then it will probably work most of the time.
John
maybe add external power source to sr-2/5 ?
on the amp specs card could give us about 31dB output power at 5V (2,4GHz 11b) :shock: :shock: :shock:
btw i have done some testing with two SR5 and two SR2 on RB 14 (same
time of course) and all was working fine, but that was only test without any transmission…
Question 1) RB11 is it Ok for a SR5?
Question 2) RB14 is it Ok for 2 SR5’s on different LDO’s and not use the other MiniPCI slots on the board.
You could also use a DC-DC converter(which is a switching regulator, as opposed to a linear regulator, and will run at closer to 100% efficiency), powered off of the 12 Volt PCI supply line, such as this one that costs about $40US… This would supply enough current for all four cards on an RB14…
http://www.cd4power.com/data/power/ncl/pdc_wpn20r_a.pdf
Edit: You could also replace the 1.5 Amp LM1086 regulator that is on these boards with an 3 Amp LM1085(or even a 5 Amp LM1084 ), but you would need to make sure that the PCI slot could supply the required amount of current(or beef up the PCI slot by soldering a jumper wire to the the supply pins), and you would need to place a substantial heatsink on the board. You could also “piggyback” an additonal LM1086 regulator(with heatsink and ample supply current) on top of the existing LM1086 to double the current supplying capacity…
Edit-Edit As Tully said, these linear regulators dissipate the additional unused voltage as heat, so your configuration is definitely going to run hotter using larger or more linear regulators. You may actually realize less heat by replacing the linear regulators with switching regulators such as the one linked to above…
Also, RB11 specifications state 5 watts available at the Mini-PCI slot, so it is safe to use a 5 watt card in the slot. RB14 is rated at 5 watts per two slots, so as long as the combined current draw between each pair of slots does not exceed 5 watts, the card in question should work OK…
Hitek
Thanks Hitek146
That was the info that I needed.
Mike
I would try to change LD regulator…
soon my result in this tread..
Regards