Strange that the tide level affects those frequencies differently.

Are you running horizontal polarity? What antennas are you using? How high are they above MSL?

Tom

use biger antennas. For a reliable link you need at least -65. Use XR5 also.

isnt DFS supposed to help with this? it will automatically pick the right frequency if the link goes down? Not sure, but worth looking into.

use biger antennas. For a reliable link you need at least -65. Use XR5 also.

Getting a small script is much much simpler, and cheaper, than installing two huge dishes.
Your suggestion is illogical.

use biger antennas. For a reliable link you need at least -65. Use XR5 also.

Getting a small script is much much simpler, and cheaper, than installing two huge dishes.
Your suggestion is illogical.

Actually, his suggestion is appriopriate. When you establish a link you have to provide enough signal strength to cover such changes in propagation. Even if conditions are better, -72dBm is low signal. It should be stronger anyways.

unfortunately off the top of my head i cant think of a way to script frequency changes off signal strength

The R5H connects at 54 Mbps at -72dB. That is neither low nor slow.
Why should it be stronger? Just to waste time, effort, money, and spectrum?

use biger antennas. For a reliable link you need at least -65. Use XR5 also.

Getting a small script is much much simpler, and cheaper, than installing two huge dishes.
Your suggestion is illogical.

use biger antennas. For a reliable link you need at least -65. Use XR5 also.

Getting a small script is much much simpler, and cheaper, than installing two huge dishes.
Your suggestion is illogical.

then I wish you a happy long struggle with your logic.
-72 is just too low to be reliable on that distance.

The R5H connects at 54 Mbps at -72dB. That is neither low nor slow.
Why should it be stronger? Just to waste time, effort, money, and spectrum?

Because you have to provide at least 22dB SNR and usually about 10 dB more to cover for propagation changes.

Less signal means problems, like what you have.

unfortunately off the top of my head i cant think of a way to script frequency changes off signal strength

Why not?
Surely scripts can check the signal strengths and change frequencies, right?

• Add a New Schedule under System>Scheduler (alternately, you could add this as a System>Script and just call it from the scheduler with '/sys scr run scriptname' as your scheduler event)
• Name it as you wish, set your Start Time as startup from the dropdown
• Set you interval as you wish (I recommend no less than 1 minute, but prefer 5 minutes to allow clients to register successfully and signals to settle)
• Paste the code below into the "On Event" box
• Edit only the last word of the first 8 lines, leave everything else as is.
  • wlanname is the name of the wireless interface to affect
  • dbm0snr1either2 means: monitor dbm only=0, snr only=1, either=2
  • mindbm and minsnr are the minimum numbers you will accept
  • freq1 and freq2 are the frequencies to toggle between (make sure they are in the correct band for your interface and country)
  • checkdelay is the number of seconds between samples
  • samplescount is the number of samples to average together during each run

:local wlanname wlan1
:local dbm0snr1either2 0
:local mindbm -85
:local minsnr 12
:local freq1 5200
:local freq2 5800
:local checkdelay 5
:local samplescount 4

:global newfreq 0
:global avgdbm 0
:global avgsnr 0
:if ([/int wir get [find name=$wlanname] frequency]=$freq1) do={
  :global newfreq $freq2
  } else={
  :global newfreq $freq1
  }
:if (![/int wir get [find name=$wlanname] running]) do={
    /int wir set [find name=$wlanname] frequency=$newfreq; :log info "Switching to $newfreq MHz due to no clients registered."
    } else={
    :for i from=1 to=$samplescount do={
      :set avgdbm ($avgdbm+[:pick [/int wir reg get [find interface=$wlanname] signal-strength] 0 ([:find [/int wir reg get [find interface=$wlanname] signal-strength] @]-3)])
      :set avgsnr ($avgsnr+[/int wir reg get [find interface=$wlanname] signal-to-noise])
      :delay $checkdelay
      }
    :set avgdbm ($avgdbm/$samplescount)
    :set avgsnr ($avgsnr/$samplescount)
    :if ((avgdbm<=mindbm && (dbm0snr1either2=0 || dbm0snr1either2=2)) || (avgsnr<=minsnr && (dbm0snr1either2=1 || dbm0snr1either2=2))) do={
      /int wir set [find name=$wlanname] frequency=$newfreq; :log info "Switching to $newfreq MHz due to dBm average of $avgdbm and SNR average of $avgsnr over the last $samplescount samples."
      }
    }

Is there a way to set tx-power without loosing the connection?

You only change the frequency from 5620 to 5660 and that makes enough difference to solve your ducting/over water wierdness issues?

RK,

It was great chatting with you and I hope you enjoy the script. It was thoughtful of you to pay for the work and then let the community benefit from it freely.

If you or anyone else should have a need for advanced MT scripting and design, please do not hesitate to call on me!

-John

INSTALLATION INSTRUCTIONS:
While I love the cmd line for everything else, scripting is not in that category.
Within Winbox...

• Add a New Schedule under System>Scheduler (alternately, you could add this as a System>Script and just call it from the scheduler with '/sys scr run scriptname' as your scheduler event)
• Name it as you wish, set your Start Time as startup from the dropdown
• Set you interval as you wish (I recommend no less than 1 minute, but prefer 5 minutes to allow clients to register successfully and signals to settle)
• Paste the code below into the "On Event" box
• Edit only the last word of the first 8 lines, leave everything else as is.
  • wlanname is the name of the wireless interface to affect
  • dbm0snr1either2 means: monitor dbm only=0, snr only=1, either=2
  • mindbm and minsnr are the minimum numbers you will accept
  • freq1 and freq2 are the frequencies to toggle between (make sure they are in the correct band for your interface and country)
  • checkdelay is the number of seconds between samples
  • samplescount is the number of samples to average together during each run

Code: Select all

:local wlanname wlan1
:local dbm0snr1either2 0
:local mindbm -85
:local minsnr 12
:local freq1 5200
:local freq2 5800
:local checkdelay 5
:local samplescount 4

:global newfreq 0
:global avgdbm 0
:global avgsnr 0
:if ([/int wir get [find name=$wlanname] frequency]=$freq1) do={
  :global newfreq $freq2
  } else={
  :global newfreq $freq1
  }
:if (![/int wir get [find name=$wlanname] running]) do={
    /int wir set [find name=$wlanname] frequency=$newfreq; :log info "Switching to $newfreq MHz due to no clients registered."
    } else={
    :for i from=1 to=$samplescount do={
      :set avgdbm ($avgdbm+[:pick [/int wir reg get [find interface=$wlanname] signal-strength] 0 ([:find [/int wir reg get [find interface=$wlanname] signal-strength] @]-3)])
      :set avgsnr ($avgsnr+[/int wir reg get [find interface=$wlanname] signal-to-noise])
      :delay $checkdelay
      }
    :set avgdbm ($avgdbm/$samplescount)
    :set avgsnr ($avgsnr/$samplescount)
    :if ((avgdbm<=mindbm && (dbm0snr1either2=0 || dbm0snr1either2=2)) || (avgsnr<=minsnr && (dbm0snr1either2=1 || dbm0snr1either2=2))) do={
      /int wir set [find name=$wlanname] frequency=$newfreq; :log info "Switching to $newfreq MHz due to dBm average of $avgdbm and SNR average of $avgsnr over the last $samplescount samples."
      }
    }

RK,

I have created a script to meet your exact specifications (well I had to add a few specs that were critical, but not considered). Please contact me via AIM (see profile) if you would like to proceed.

The script features the following:
Global variables to set desired minimum dBm (default=-85) as well as minimum SNR (default=12), interface name (in case you have more than 1 wireless interface in the AP, default=wlan1), the two frequencies (default=5200,5800), a check delay in seconds (checking 4 times as fast as possible rarely produces different numbers, so I put a short delay between each of the 4 values to be averaged, default=5), the number of checks to average together (default=4) and the ability to choose whether you are swapping based on dBm (default), SNR, or either. Finally, it logs all frequency swaps as script info, showing the frequency it changed to as well as why (no clients or it lists the average dBm and SNR values).

It will swap frequencies if NO clients are registered (in other words, signal so poor they dropped) as well as if they are registered but do not meet the qualifications you specified in the variables.

You will be able to get it to execute as often as you like using the System Scheduler, and while you can choose 30 seconds if you like, I would recommend something more like 1 minute as a minimum and 5 minutes preferred. Bringing the link back up within 5 minutes is still a might better than having to keep an eye on it. Plus, with a longer time between execution, you may wish to increase the number of samples in the average or extend the delay between samples.

Besides the variable definitions and easy to read formatting, it's just a lean 12 lines of code for fast execution and low cpu overhead.

-John