Hardware for 3.5km Wifi Bridge

Hardware Questions and Recommendations
1

Hi All,

I am in an amateur radio (ham radio) club and we have a radio tower on top of a hill. It is connected to the internet through 2 ubiquiti Litebeam dishes. One dish is on the Tower and the counter part in the valley at a friend's home.
They both run OpenWRT.
This dishes have proven to be unreliable, both with OpenWRT or original Ubnt firmware. The dish on the tower partially failed during a thunderstorm which was quite far away, it needs constant reboot. Add to that that the mechanical parts are quite wobbly.
As a matter of fact we are looking for some replacement hardware, ideally if it could run Openwrt that'd be great.

Requirements

  • Immune against electrical discharge
  • Able to output at least 30dBm between 5650 and 5850MHz (as licensed ham radio operators we are legally allowed to use that much power.
  • Being mechanically sturdy.

Thanks for your input :slight_smile:

1 Like
2

I can't help with this specific question, but just wanted to say hello from a UK amateur radio licensee. There are a fair number of amateur radio enthusiasts on this forum, and the integration between OpenWrt and amateur radio certainly interests me.

1 Like
3

You, clearly, have identified the antenna and alignment as issues. 3.5k has very little tolerance with misalignment with only 30dBm. Dishes may offer more tolerance than a Yagi but you know you would get more signal.
Regardless: why is stabilizing and aligning them not the first thing to fix?

Is your lan ethernet?

4

A Yagi should give decent reception.

I've read quite a few instances whereby cheap components conquer massive distances - just through the use of good alignment and hand-made waveguides.

Maybe some inspiration here: https://en.wikipedia.org/wiki/Long-range_Wi-Fi

I cannot find the original blog articles since search engines are awash with SEO spam which drowns the originals out.

5

5AC or M5?

6

Are the lans using a cable or wireless?
What country?

7

Thanks for all the replies.

@LilRedDog 30dBm (1W) on a 25dBi gain dish boils down to an effective radiated power of 55dBm (316W) on a regular antenna. It is plenty enough power. Professional Point to Point links use similar power figures.

The mount consists of a ball joint system, it is wobbly by design. We know for sure one of the AC chain on the moutain unit died a few weeks after we mounted the dishes. A few weeks later alignement was corrupted by strong winds. It is a 30m climb on an old Tower or we need to rent an aerial lift. As a matter of fact, if take some action we will replace the whole hardware.

The dishes are wired and powered using PoE.

We are in France.

@systemcrash A Yagi would do, but yet we need to find the proper networking device.

@hecatae It is 5AC version.