Hello guys,
I’m using an Heltec HT-M02 in my open pitch mine. I did some site survey and works just fine with two directional antennas. Now I putt 4 directional antenas and the covarage seems to be reduced.
Do you guys thing that can be something about the power of the antennas? I’m not an expert in this issue.
Following some photos of the project:
Here the datasheet of the antenna:
Please any advice will be very welcome!
Is there something wrong with your receive or transmit?
could you provide the para of 4-way power divider?
You just mentioned: It’s normal in two directional antennas… do you use the 4-way power divider or 2-way power divider(for two directional antennas)?
I think it’s not helpful for the covarage using the 4 antennas. The antenna gain is 7dBi，But a 4 ways divider’s insertion loss is at least 6 dB. In this case it equivalent to connet a 1dBi omnidirectional antenna.
@jasonXu
The problem is with the gateway received packets. I aware that 4 antennas could result in a reduction in the transmitt part of the gateway however I didn’t know that these 4 antennas could reduce the reception part in the gateway side. We were using these antennas because I did some site survey and the covarege was really better than a ominidirection antenna.
@jasonXu we use a single 4-way power divider.
@Supporter always that i putt some parallel antennas I will have reduction even in the reception side? Thanks for the advice!
Using a splitter is completely useless. One issue is the reduction of power to each antenna -6db but more importantly is the phasing of the antennas Beams will not be correct as no phasing harnesses has been used And would be difficult to design and implement the phasing of the beams . And as an asides an antenna Is the same for Tx And Rx so the receive will be -6 dB though the splitter and then the phase interference from other antennas which is unlikely to add any gain more Lilly loss. Just use a food omni antenna that does not have a very high gain as that could lead to a beam pattern than will be very narrow and not cover all the site and could need a down tilt that causes even more problems. Buy a goo antenna that has say 6-8dbi gain and is designed to not require a ground plain and not one from China as most do not meet spec in my testing. Simon
From the images it looks like you have used a couple of T connectors to connect the antennas.
If you are connecting 4 antennas to the one radio output or even 2 antennas to the one output you will need to phase them correctly. You can do a cheap and nasty phasing harnes using Coax and tune all your coax feed lines corectly but you will need to know what the feedlines are that are integreated in to the antennas.
The other issue is for every connector you have inline you reduce your db, same goes for any splitters etc. Same goes for lightning arestors.
I would agree with @Sivaelid. use a good quality omni or even better yet a monopol with a ground plane.
