Cards losing signal.

RouterOS Wireless Networking
1

Hi,

I have run across a problem of late and am stumped for a solution.

I have noticed that certain cards are suddenly losing 10-20dB signal for no apparent reason. The cards include the Mikrotik R52 (abg), Senao NMP-8602 (abg) and Senao NMP-3602 (bg).

The information I have is:

  1. The cards are at various sites spread across the city and are not always in the same area.
  2. The signal strength drops to -91 to -94 from a range of -70 to -80.
  3. Some sites do not have the routerboard earthed. (earthing the board in some, but not all, cases prevents the problem from re-occurring)
  4. Some sites do have the routerboard earthed.
  5. The problem re-occurs at the same sites.
  6. The power feed to the sites vary. Some are municipal AC, others are UPS and others battery.
  7. One site changed the card to a CM9 which lasted longer, but also lost signal.
  8. A Senao SL-5354MP has worked at a problematic site for 3 months. The routerboard was replaced recently and the new R52 card lost signal overnight.
  9. The cards mostly (but not always) lose signal overnight.
  10. The weather does not seem to be a factor as this has happened in good or bad weather.
  11. All cards are Atheros based chipsets.
  12. Time between installation of card and loss of signal varies from 3 weeks to 5 minutes.

Does anyone have any ideas?

Regards,
Wispy

2

From what you are describing it sounds like you are having the same issues as in this thread.. http://forum.mikrotik.com/t/wireless-card-recieve-blows-issue/7930/1

You basically have two options..

Replace your antenna’s with antenna’s that are DC Grounded.

Replace your wireless cards with XR2/XR5’s..

I went through over 40 cards before I figured out what was causing it.

-Gerard

3

I don’t remember seeing that the XR5 had the same improvements for the grounding and voltage tolerance. Can anyone confim if they do or not?

4

AFAIK the XR5’s do not have a diversity switch, and the diversity switch is what is failing on the other cards.

-Gerard