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Hi

I have a ship with four pontang omni 493 omnidirectional antennas installed, two on each side of mast mounted vertically and horizontally separated and connected to a RUTX50 modem.

I've noticed in some very remote locations in which only one 4G cell tower is present with one transmitter (1x1). On the rutx50 only one of the mobile antenna ports on the modem can be used to receive this signal rather than any of them. I understand that there is only one transmitter and cell tower but my question is, why can't the modem then simply operate in SIMO? and thus try to receive this signal across any of the four antenna ports?

The reason I'm trying to find this out is all the antennas have a minor obstruction being the ships mast, hence as ship pivots around it would be good if any of theses antennas can capture the single cell towers transmitters signal in a SIMO method.

I also understand that when a MIMO tower is present the above issue will no longer be a problem.
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Hi again

So I've got the system up and running and with these high gain long range omnis it is able to connect to multiple bands including 4G and 5G.

I still seem to find that antenna port 0 appears to be the "make or break" port.. For example if I plug into port 1 2 3 and leave port 0 unplug it doesn't seem to get any signal at all? Why is that? I thought port 3 would function?

Is there a way i can test every antenna, I don't see any info in the GUI about each antenna, i just want to make sure there all available / working.

I would like to confirm that MIMO is operating (when i have a mimo tower)
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It is likely that fact that 0 port acts as the primary transmission port and you are in an area with poor transmission. From some testing I have done, in most cases, even without antenna attached to port 0 decent speeds were achieved.

The router itself, unfortunately, does not have features to measure/evaluate the input of each antenna port separately, the AT commands manual does contain such commands as well.

Overall, the device is intended to be used with all antennas attached, thus I suggest to have that whenever possible.

Best regards,
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Ok so I figured out the problem and it's actually nothing todo with the antennas, the problem is the tower closest to me with the best signal strength is a telstra very low capacity (98mb) single transmitter tower using 4G band 28 or 750 mhz. My modem keeps connecting this tower and does not seem to want to use weaker but much higher capacity towers. I went to band select and I disabled 4G band 28 and as soon as I did that the modem used another tower and performed CA between multiple 4G bands and even used a 5G band and the speed shot right up to around 70mbps. The annoying thing is I don't want to have disable 4G band 28 entirely... Because if the modem connected to a MIMO 4G band 28 tower with more bandwidth, then it would be one of the best bands due to how far the signal can travel.... Problem is we will be on project in this location at sea for awhile.. Is there any kind of script i could run on my modem so that higher frequency bands are utilised first? Or some way around this besides blocking B28? Once again really appreciate your support.
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Band and cell tower selection is performed by the modem module, which runs software from Quectel.

However, if you know that you are going to be stationary for a while, you can lock router's modem to a specific cell tower, and reset to automatic cell selection afterwards. For further instructions, refer to this page. 

Alternatively, if you can send/receive SMS to the device, you can configure multiple device configuration profiles: one with band 28 disabled, the other with the same band available. 

Profiles can be created in System -> Profiles -> Profiles page. Profile to be used can be set via SMS remotely, a scheduler, which is also available in the WebUI, or by triggering the input pin of the device.

Best regards, 

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Hi so I ended up keeping prim 0 and diversity 0 on the same sides separated by spacial diversity likewise otherside was prim 1 and diversity 1. The prim of both are the upper antennas. I believe though an element of horizontal diversity was introduced when swapping port 1 and 2 around, the vertical diversity effect was reduced due to obstructions and hence the throughput seemed less. I'm no expert but i think the vertical spacial diversity of prim and diversity antennas being on the same side vertically separated out performs have the two diversity antennas crossed over.. Any thoughts?
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You should stick with what gives the best performance.

Could you try to perform some speed tests, with diversity antennas from ports 1 and 2 disconnected, to check, how much of an impact do they have on overall throughput?

Best regards,

3 Answers

+1 vote
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Hello,

The thing to note about RUTX50 is that different antenna ports serve different purposes. However, in any case, the device has one primary and one diversity antenna for receiving signals of each frequency range (lower/middle/high/ultra high).

Thus, in order to increase the reception area I would suggest to try a different antenna arrangement, as it depends on how the antennas are distribted in your case.

Best regards,
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Hello

Firstly thanks for your information it's much appreciated and will help me configuring them, as I will make the upper two antennas located port and Starboard of vessel the prim and diversity.

And the lower two antennas can be number 3 and 4.

Can I make a suggestion that this is actually illustrated in the routers manual? And also on the box of future production? Currently all it says is mobile for all four ports giving no indication of which is the primary, diversity and the other two.

Thanks
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Hello,

It is always advised to use RUTX50 with all four antennas attached for the best performance. Besides, technical details can get confusing for many users and antenna arrangements become relevant in more elaborate cases such as yours.

I will, of course, address your suggestion for consideration.

Regarding your setup, based on the picture you have provided, I would suggest to place antenna 4 above antenna 2, as antennas 1 and 4 (I assume they correspond to most left and right ports on the router) are used for transmission, thus placing them higher, would provide a better line of sight as well as better coverage.

Best regards,
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Hi thanks for the info but I'm a little confused.

Let's imagine we looking at modem and have port 0,1,2,3 as per your photo. Left to right.

Are you suggesting? I have port 0 and 3 antennas as the highest antennas located port and Starboard of mast and then having 1 and 2 as the lower antennas. Should i place 1 under 0 and 2 under 3?
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That is indeed the arrangement I suggest to try.

Best regards,
0 votes
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Thanks for your on going help

Attached is the current antenna layout / port config i'm using (the one you suggested)

I guess I have a unique situation at present in which the only celluar tower near is a 1X1 transmitter at 750 Mhz, the signal strength is fairly strong and I can achieve 40 mbps speeds when port 0 antenna has line of sight in our project location when connected to this tower. The issue is because the modem is only using port 0, when the vessel is facing a certain position (heading) while at this fixed location at sea, the ships mast obstructs this signal to antenna 0.

Please see my antenna layout photo below, I guess my question is, would there be a way to capture signal no matter which position the vessel is facing? could I perhaps have port 1 (diversity port) connected to the lower antenna on the oppersite side of mast? that way with a 1x1 tower transmitter scanario like mine which is fairly uncommon, we can collect this signal in almost any position at this location without the mast obstructing  during certain headings? Or am I not understanding things correctly?

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I guess what I'm trying to say is currently i believe due to the cellular tower (1 lte transmitter only) the rutx50 modem is only operating in CAT1, therefore my question is, to improve received signal on both side of mask, shall i have the primary antenna and the diversity antennas opposite sides. Thus this would be swapping ports 1 and 2.
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Try that.

In theory, the way diversity works is that it compares signal received on the primary antenna to some threshold value and uses the signal received on that primary antenna for further processing, if that signal is above the threshold.

If the signal is below the threshold, signal on the diversity antenna will be checked. Thus, if the diversity antenna is on the side, where signal coverage is better than the one reaching primary antenna, diversity antenna should be utilized.

Best regards,
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Thanks for your answer yes that's exactly what I'm trying to achieve here! Understand once we reach a mimo lte or 5g tower this won't be as much of an issue but at the moment with this single transmitter I'm getting poor downlink at certain headings due to the primary port 0 and diversity port 1 being on same aid of mast. I will try it now.

Kind regards

Aaron Giovenco
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It would be interesting to hear your feedback, as I have never seen RUTX50 yet used in such configuration.

Best regards,
0 votes
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Will do shortly.

Problem is very dynamic environment.

Last night connected to 4x4, single band 750 mhz LTE tower and was pulling 50mbps up and down which isn't bad.

Main issue is high signal to noise teletonika environment but on a ship that's very hard to reduce with omnidirectional antennas unfortunately.
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Didn't mean to write teletonika*