The addition of RF elements horns to a PTP550 link

In a previous series of articles we talked about a new Cambium 550 link and the noise challenges we had.  You can start your reading in Part one and Part two.

Due to the frequency challenges, we decided to upgrade the dishes to RF Elements Ultra Horns.

If you recall our spectrum looked like this before.

After the horns. While not a night and day difference you will notice several improvements across the band.  Less red and yellow on the scan and sharper drop-offs. We saw the most improvement in the 5160 area and the 5720 ranges.  And this is with the horns pointed right at the source of most of the 5GHZ noise.   Not much you can do if you are pointed right at the noise.

What did this mean for the link? It meant we were able to find a 200 meg increase because we were able to obtain better modulation on the link.

So while we were not able to filter out all of the noise we wanted, we were able to increase our MCS rates on a very noisy link to increase bandwidth and increase the reliability of the link.  Before the horns, the MCS rates would be in a constant state of flux dealing with noise.

PTP 550 continuation

In a previous post, I mentioned a 5-mile link using Cambium PTP550s and why frequency matters. Today we enabled the second radio and have some results from that.  First, let us talk about some of the parameters.

As you can see from our frequency scan we have a very noisy frequency.  Without DFS we have very few open channels.  Due to this, the results you will see later are not optimal.  The limiting factor is the noise on the band.

After much channel selection, this is what we ended up with. As you can see we are just running a 40mhz and a 20mhz channel.  This is because the band is so noisy.

As a result of the frequency, this is what we have ended up with for quality and capacity. The second radio is less than optimal, but it is passing solid data.

So what do speed tests look like across the link?

Single Radio Speedtest

Using channel bonding

Some of you may still be asking, it should be more. If you have noticed the noisy frequency band has been the greatest factor on this link.  In the quality and capacity screenshot, you will notice the 2nd radio only has a 45% capacity.  This is due to channel selection. If we could get better channels this would improve the link.

Wo what is the answer? Better backhaul antennas are upgrade number 1.  Currently, we are using UBNT 2 foot dishes, which were chosen due to the gain needed on this link. Secondly, when DFS is certified for these radios we will have more channels available.  The frequency scan shows the DFS channels are less noisy in this area, which will increase throughput.

Just for giggles, we had the tech on-site run a speedtest.  This was through a wireless router with a 100 meg ethernet port plugged into the local router.