We are using the Mikrotik R11e-2HPnD, which is a MIMO radio device. We are using a Gateworks modem on top of this for the web interface. We are trying to get HD video from one point to another using 2 radio sets. However, after certain distance we are able to ping, but no video is being obtained. Could this problem be due to the improper pointing of the antenna ? We are using a 24dBi Tp-Link directional antenna on the ground & 5dBi antennas over the transmitter. Kindly let us know if anyone has faced this problem ?
It could. Mentioned device is just a wifi card, you need to analyse what the hosting devices on both sides say about the link quality and check the rest.
Thanks a lot. We also analysed the RSSI at the receiver & found that it was around -54dBm. This was at a distance of approximately 2 kms. The MCS being used at the radio was MCS2 . The camera encoder feeds the transmitter radio at 11Mbps max for a 720p quality. So I wanted to make sure if it was only the problem with the pointing of the antenna or any other reason. The test was carried out in an open field in a remote place with no interference. The transmitter antenna gains were 5dBi & the receiver as I mentioned earlier was 24dBi. I also used another LCom Directional antenna of 18dBi, but with the same results.
Very insufficient info. How the link exactly looks like? What are the devices on both sides? What sustained data flow are you able to pass with which ccq? What are the signal levels on both sides? What are the spectral scan results?
The link consists of a Mikrotik R11e-2HPnD device at the transmitter & the same device at the receiver. The terrain is basically something like a grassland & the transmitter was at a height of around 10ft above the ground level & the receiver is at the ground level. They are separated by a distance of around 1.6Kms.
Since it is a MIMO device, we use 2, 5dBi Omni-Directional Antennas at the transmitter & 1 Omni-Directional (5dBi) & a Directional antenna at the receiver. The transmitter is connected to a camera for streaming HD quality data flow at the input (720p) which outputs the data into the radio at 3Mbps.
The data flow obtained at the receiver was an average rate of 13 Mbps & the ccq waqs 80%. The RSSI at the receiver was -54dBm. Since it was a remote area, we did not do a spectral scan as there are no other devices in the vicinity. I have attached the snapshot of the page of the receiver for your reference taken at the point when the streaming failed. Thanks a lot for your time.
You should use directional or at least panel antennas on both sides and the same for both chains or better dual polarised antennas. Make sure the fresnel zone is free, you could need to rise the antennas higher above the ground level. Consult configuration questions on openwrt forum or the forum related to your devices, you are definitely not running ros.
Thanks a lot. Therefore it will not be feasible to use directional antennas at the transmitter & the use of omni-directional antennas on the Transmitter is a better option for us. We use simple 5dBi rubber duck antennas on the Transmitter (2 in number). Therefore by your suggestion, we can obtain a fresnel free zone in this case, right ?
I am really sorry for I did not understand what ros stands for ?, but I will post the same query on the openwrt forum as well . Thanks a lot for your time.
Ok. Ros stands for routeros. In this case you should have bigger antena on the vehicle maybe just one single chain, set fix low mcs to avoid jumping between modulations and on the base use panel or a set of panel antennas to cover necessary range. These things are very hard to guess and estimate, you need to test and try what fits the best. But it is general discussion about wifi physics.
Thank you, that is correct as we do not use the ROS with the MIMO radio as it is a min-PCI based device. However we also have a Mikrotik Metal (R2SHPn) which has the ROS & hence the necessary flexibility in order to set the MCS & Transmitting power & several other parameters. We will also test with this as you have suggested & will check. Thanks a lot for your time.
