Packet loss C5x





Good day

I have deployed a backhaul between me and a high site consisting of a C5x between both sites and a 30dBi parabolic dish on each end. (My point is just a relay between the studios and the high site)

I use this to send audio to the FM transmitters of 2 radio stations. The traffic is very minimal on the link - about 500kbps with both audio feeds.

When using the audio encoders at the studios which send the audio with the RTP protocol which uses UDP, you will get the occasional glitching sound on radio.

I then created a streaming server on my server where the studios will use software on a PC to encode the audio from the audio interface and stream it to my Icecast server. The decoder at each FM transmitter will connect with my server over the backhaul to receive the audio feed. From time to time the audio will go silent on radio and then start playing again. This happens when there is a sudden huge amount of packet loss over the backhaul and the decoders buffer runs empty.

I have written a script on my Mikrotik router to monitor the backhaul radio on the high site end as well as the decoders at the transmitters. The script just ping the devices with a packet size of 1000 and a timeout of 30ms and logs it in the Mikrotik router log.

What can I do to reduce this packet loss or completely eliminate it?

I have included screen shots of backhaul radio dashboard information as well as the spectrum analysis.

I hope the information is sufficient. Let me know if more information is needed.

Kind regards,
Claude

Try to change frequency and reduce channel to 20mhz and test it.

Hi Jorge

Thanks for the reply.

I have changed the bandwidth to 20 MHz, but it didn’t made any difference. There is a lot of consecutive packet losses for about 3 seconds and the audio drops out on FM radio. My script on the Mikrotik router does a ping with a time out of 30 milliseconds and packet size of 1000.

I will try a few different frequencies. The spectrum view from the C5X shows that the link between me and the high site is very congested.

I will reply with my findings of changing frequencies in a few days.

Thanks