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mikrotik_rb_751g-2hnd

Mikrotik RB 751G-2HnD

From documentation

Wireless device RB751U includes a 2GHz 802.11b/g/n wireless device built in. It has PIF (Planar Inverted F-Shaped Antenna) type antennas (2.5dBi) built into the case, and one MMCX connector for an optional external antenna.

RB 751U has 3 built-in wireless antennas:

  • Chain0
    • one antenna for TX
    • one antenna for RX
  • Chain1
    • one antenna for TX/RX
    • MMCX connector for external antenna

To enable the external MMCX connector, set “antenna mode: antenna‐b” in RouterOS wireless settings, in the HT tab of Winbox. Note: enabling the external antenna disables the built-in Chain1 antenna.

Default antenna setting

  • Use both chains for TX and RX.
  • Chain0 tx and seperate antenna for rx.
  • Chain1 tx/rx antenna.
    antenna-mode=ant-a
    ht-txchains=0,1
    ht-rxchains=0,1

Antenna settings

All internal antenna's disabled

  • Disables internal antenna chain1.
  • Disables tx/rx on chain0.
    antenna-mode=ant-b 
    ht-txchains=1
    ht-rxchains=1

Seperate tx & rx antenna's (chain0)

  • Disables internal antenna chain1.
  • Enables tx/rx on chain0 (seperate antenna's).
    antenna-mode=ant-b 
    ht-txchains=0
    ht-rxchains=0

Only one tx/rx antenna (chain1)

  • Disables internal antenna's chain0.
  • Enables tx/rx on chain1.
    antenna-mode=ant-a
    ht-txchains=1
    ht-rxchains=1

Transmit power settings

Maximum radiated power in The Netherlands is 100mW / 20dBm (e.i.r.p.).

Real vs Total tx power

  • Real tx power = single chain power
  • Total tx power = dual chain power

Example:
14dBm + 14dBm = 17dBm (logarithmic)
25mW + 25mW = 50mW

Configure tx power

Antenna gain in dBi, used to calculate maximum transmit power according to country regulations.

  • Antenna gain:
    antenna-gain=2
  • Frequency mode:
    frequency-mode=regulatory-domain
  • Country:
    country=netherlands
  • TX power mode:
    tx-power-mode=default

Current tx powers

  • Show current TX powers:
    /interface wireless> monitor wlan1 once 
                     status: running-ap
                       band: 2ghz-n
                  frequency: 2472MHz
          wireless-protocol: 802.11
                noise-floor: -109dBm
             overall-tx-ccq: 40%
         registered-clients: 0
      authenticated-clients: 0
                wmm-enabled: yes
          current-tx-powers: 1Mbps:14(14/17),2Mbps:14(14/17),5.5Mbps:14(14/17),11Mbps:14(14/17),6Mbps:14(14/17),
                             9Mbps:14(14/17),12Mbps:14(14/17),18Mbps:14(14/17),24Mbps:14(14/17),36Mbps:14(14/17),
                             48Mbps:14(14/17),54Mbps:14(14/17),HT20-0:14(14/17),HT20-1:14(14/17),HT20-2:14(14/17),
                             HT20-3:14(14/17),HT20-4:14(14/17),HT20-5:14(14/17),HT20-6:14(14/17),HT20-7:14(14/17),
                             HT40-0:15(15/18),HT40-1:15(15/18),HT40-2:15(15/18),HT40-3:15(15/18),HT40-4:15(15/18),
                             HT40-5:15(15/18),HT40-6:15(15/18),HT40-7:15(15/18)
        notify-external-fdb: no

Frequency

Channels (Europe)

ChannelFrequency (MHz)
12412
22417
32422
42427
52432
62437
72442
82447
92452
102457
112462
122467
132472

Channel 13 / 40MHz

  • Band:
    band=2ghz-b/g/n
  • Frequency:
    frequency=2472
  • Offset 0:
    frequency-offset=0
  • Possible widths: 10mhz, 20/40mhz-ht-above, 20/40mhz-ht-below, 20mhz, 40mhz-turbo, 5mhz
    channel-width=20/40mhz-ht-below
  • Dynamic Frequency Selection off:
    dfs-mode=none
mikrotik_rb_751g-2hnd.txt · Last modified: 2014/08/29 08:30 by admin