Hello,

we have done some testing. We have Point-to-Point link with the same devices on both sides, the same directional antennas. The only difference is that on the one side we installed Atheros CM9 and on the second side Atheros SR5. On both side we limited communication speed to 6Mbit and configured the same values for tx-power.

We suppose that there should be different signal level on both sides according to fact that SR5 uses 400mW and CM9 under 100mW.

But the signal level is the same. So how can I exploit feature of 400mw?

On both side we limited communication speed to 6Mbit and configured the same values for tx-power.

We suppose that there should be different signal level on both sides according to fact that SR5 uses 400mW and CM9 under 100mW.

But the signal level is the same. So how can I exploit feature of 400mw?

If you set the tx-power the same on both ends, then both ends are transmitting with the same power. You would expect the power levels to be the same in that case. If you leave the tx-power at default, the sr5 will use higher tx-power than the cm9 is capable of, and you will see higher rx signal on the cm9.

But I need to compare maximal values.

You know, we would like to use SR5 cards for long-range link but after installation our pratcical tests says that results are the same with SR5 or CM9 cards. How is it possible?! I suppose I should get better signal level using SR5 thanks to ability to transmit higher power.

Maybe I misunderstood what you said. You said you configured the tx-power to the same on both ends? That means (to me) that you set the tx-power to the same value on both ends, which would mean you are reducing the tx-power on the sr5. Is that correct? Leaving tx-power to "default" will give you maximum output power on both cards, which is what I think you want.

yes, please leave `tx-power` to `default` if you want the cards to work at their maximum. if you change this value, the cards will not work as good.

yes, please leave `tx-power` to `default` if you want the cards to work at their maximum. if you change this value, the cards will not work as good.

If you are not in Region 1 (Brazil, Canada, Taiwan, USA) and aren't a newly minted idiot like me, you may want to skip reading the rest of this post

Certainly YMMV and we may have made a cockpit error, but we think it is true that when we follow that suggestion, namely "leave `tx-power` to `default`" (and certain other ducks are lined up as required), we get 19 dBm for the power output of a RB532+RouterOS+SR5 for 6-24 Mbps, 15, 14 and 13 dBm for 36, 48 and 54 Mbps, respectively, on station units. Reference: Winbox/Interface/Advanced Status. We haven't yet found the idiot light for the master unit

If our readings are correct (and that is a big IF), that falls a tad (actually 2-6 dB short of the power necessary to put a RouterOS link, e.g., in parallel (for redundancy) with other commercial equipment (Orthogon, Trango Atlas, et al) which are claimed to output 21-25 dBm to the integrated antenna which is typically 23 dBi.

We may have found that a RB532+RouterOS+SR5 with a configuration as seen below the sig is _said by the Advanced Status tab_ to produce 22 dBm at 6-24 Mbps, which gets us into the range of other commercial equipment with antennas which can be supported by typical extant towers in our rural area in which towns are typically 25 miles apart (lore: the distance a stage coach could go in a day). A lot of times, the country side is peppered with smaller communities at say five to ten mile intervals.

What are the reasons a configuration which doesn't follow "leave `tx-power` to `default` "will not work as good"?

a) the routers will fall over (Internet dean Randy Bush's famous words in the pagans discussion)
b) the power supply will fall over
c) the SR5 will fall over
d) all of the above
e) some of the above
f) none of the above
f) something else of your choice.

Thanks for your time and thanks for sharing your knowledge of facts gained through more experience than we've had to date with MikroTik.

Kind regards,

ldv

[vaden@LabTest] > interface wireless print
Flags: X - disabled, R - running
0 R name="wlan1" mtu=1500 mac-address=00:15:6D:10:36:67 arp=enabled
disable-running-check=no interface-type=Atheros AR5213
radio-name="00156D103667" mode=station-wds ssid="LabTest" area=""
frequency-mode=manual-txpower country=united states antenna-gain=0
frequency=5825 band=5ghz scan-list=5745-5825 rate-set=default
supported-rates-a/g=6Mbps,12Mbps,18Mbps,24Mbps,36Mbps
basic-rates-a/g=6Mbps max-station-count=2007 ack-timeout=dynamic
tx-power=22 tx-power-mode=card-rates noise-floor-threshold=default
periodic-calibration=default periodic-calibration-interval=60
burst-time=disabled dfs-mode=none antenna-mode=ant-b wds-mode=dynamic
wds-default-bridge=wds-bridge 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 preamble-mode=both
compression=no allow-sharedkey=no