Help me with this B5C Link x 2

I have just setup a B5c Link over 14.6 Kms using B5c x 2 with 25dbi antenna. This link has 2 x 40 channel width.

the problem is the differential tx 448 and Rx 603 speeds which may be due to the Stream 4 not working
Tx steam details

Rx stream details:


is this an antenna problem – as a Hardware issue or is it due to alignment ?

Thanks in advance.

My first guess would be alignment + noise on the link. (Your chains are all over the place and you have < 22 dB SNR on most of your chains)

I would also check to make certain that you have a clear Line of Sight between the two radios and that you don’t have anything impinging on your Fresnel zone with Mimosa’s Design Tool (

I frequently see a similar problem, where one of the four chains either doesn’t connect or the indication in the radio is wrong. I don’t know which – the paths usually have some clutter, which could impact one polarization more than the other, but it only happens on one of the two frequencies. This happens on several of our dozens of B5c’s. It’s a mystery.

But your configuration shows an error, the antenna gain set to 0 dB. Thus your EIRP is shown as +24 when it’s really +49, if you have a 25 dB antenna. And you have the RSSI to prove it. I don’t know what country you’re in but I know in the US those frequencies are limited to 30 dBm EIRP, so that’s a total of 5 dBm conducted if using a 25 dB antenna.

Thanks William5 and Fred. BTW: Fred I’m not in USA.

We did work on the alignment – will little joy. Fred,William5 , Ive got noise on the link and am working on slanting the antennae to get a clearer channel. Hopefully this will allow me to get a 80MHz channel too. Any other suggestions?

will keep you posted.

Bigger antennas, 14.6 km is quite the distance.

I am curious what antenna you are currently using. RF Elements?

Looking at Mimosa’s Design tool, which is moderately accurate, you should be seeing 58-61 for your chains and there should be no reason for the chains to vary as much as they are.

what type of antenna you using?

A basic 25dbi oem brand from my supplier.

BTW: got it working really well at a Slant of 45, single chain, 80MHZ.

Phy connection 650 +650 … and throughput of 450-500 mpbs.

Signal strength of 58 - 60dbi.