In our current setup, we’re using a Tektelic Kona Macro gateway that is outputting the max 27dbm as per NA regulations that currently has a 3dbi antenna. The gateway is mounted approximately 35m high while the two devices (Barani MeteoHelix and MeteoWind) we’re having connection issues with are just over 5km away. We should have a good line of sight to them with no significant obstructions in the way. We should be receiving uplinks about every 10mins, but at times there are large gaps between communication (sometimes over an hour). The MeteoHelix is seeing RSSI values consistently between -100 and -105 with the SNR values varying a lot, but typically being less than -2/-3 (sometimes as low as -9). The MeteoWind shows slightly better values across the board while also being slightly more consistent with uplinks.
We saw significant improvement after mounting the antenna to the east side of the pole it was mounted on, facing the direction of the devices compared to the opposite side it was on. We can perhaps try and mount it even higher up as well.
I’ve been researching antennas, their workings, and how they effect the communication with devices. It seems as though a 3dbi antenna like we have is rather low and I’m curious if upgrading to about a 6dbi antenna would improve the situation. I understand that too high of an antenna gain will reduce the beam width, which would negatively effect its span. I’m curious as to how drastic this trade-off is with the more dbi an antenna has.
If anyone has any suggestions / advice regarding this it would be greatly appreciated.
Rather than the Forum volunteers having to go off and research can you provide links to the devices you are using?
In general and in most parts of the world if the transmitter device (be it GW or node) is set to the max local limit then that limit is generally set assuming a specific gain for the associated device antenna - typically a 2.15/3.1dbi device with a good polar coverage. Moving to a higher gain device generally assumes that increaed gain is achieved by concentrating the delivered real world tx power into a narrow beam, as you have read, delivering a higher EIRP in the line of the beam. Where there are limits to TX power this usually then means you have to reduce the physical TX power to keep the beam power within the EIRP limits.So short answer is no a higher gain ant is effectively a zero-sum game and no benefit overall is acheived, though such techniques can be applied when looking to specifically reach/hear a targeted node at a given distance/direction.
It should be noted that as the gain increases so real world ant’s start to deveate from the classic/ideal isotropic radiation pattern and either a beam deflection (up/down/horizontal - dpending on how engineered and target deployment application) and/or notching in the beam polar diagramme starts to appear. This notching can cause its own problems as it is a reduction in sensitivity around the notch - think of the ant as drawing an archery target with different rings of sensitivity centered on the device…improving sensitivity out to the horizon can cause a reduction in gain at intervening points…deploying a beam targeted to the horizon say 10, 30, 50km away might cause problems at say 4-6 (oops!), 12-15, or 18-24km away or whatever.
Without us doing investigation can you confirm if the nodes also have 2.15/3dbi ants attached? If not and if they are say 0dbi, -3dbi, -7dbi or whatever, then there is scope to improve by enhancing the node ant, keeping the GW ant as is.
Even an apparently solid signal can sometime show variability depending on local environments - local interferers etc. - or intervening objects - a passing train, lorries, even buses etc that pass between nodes and GW’s…
How close to the pole is your antenna mounted? Too close and the pole will distort the field of the antenna resulting in unpredictable results.
I’ve seen 3dbi antennas on both node and gateway result in excellent result for over 10 mile line of sight deployments with hardly any missing uplinks.