Max Transit Duo - the two modems report different connection qualities


#1

Background:
We have a Max Transit Duo with both modems equipped with Verizon SIM cards.
When connected, the dashboard reports one as being “Connected to Verizon” and the other as being “Connected to VZW”

The details are also different:
Cellular 1 reports

  • LTE Band 13 (700 MHz)
  • RSSI: -44dBm SNR: 17dB RSRP: -74dBm RSRQ: -13dB
    Cellular 2 reports
  • LTE Band 13 (700 MHz)
  • RSSI: -57dBm SNR: 0dB RSRP: -82dBm RSRQ: -10dB

Why would there be this quality difference between cellular 1 and 2?


30LTE vs 20+usb modem
#2

Suspect that the cellular connections is connected to different nearby cell towers this why different signal info displayed. Beside that carrier info “Connected to Verizon” or “Connected to VZW” is query from the cellular module and look like different info returned by the carrier.

Please further compare the Cellular Engineering data to confirm the Cellular 1 & Cellular 2 connection status.

Do further check on the “Cell ID” for the cellular connection and it should give you some hint for the different.

Please open a support ticket here for support team to check if you need more help.


#3

Hello @zegor_mjol,
To add to @sitloongs comments, we normally do not use the antennas supplied with the routers from Manufactures except for pre-delivery configuring and basic testing.

The antennas we use vary depending on the customers site and requirements.
Results are also affected by:

  • 700Mhz travels a long way, it is normally in a high density areas to have connections to multiple towers
  • the way you have connected the antennas (cabling type & quality, length of cables, connector types)
  • the antennas you have chosen to use
  • the proximity of the antennas to each other and other RF equipment
  • the layout and angles that the antennas are install

Here are results from a MAX Transit Duo as monitored from within InControl2, even through both SIM cards are for the same ISP, one of the modems shows the Carrier name in all capital letters and the other is in lowercase letters. You can also see here that the each of the modems are tuning to different towers by the Cell ID.

(click on image to enlarge)

Happy to Help,
Marcus :slight_smile:


#4

Thanks for the information. According to IC2 they both connect to the same tower, however the MAX Transit reports that the cell IDs are different (off by 1 from each other).

The location is rural, so there really is only one tower here.

The set-up is that the MAX Transit is in a basement surrounded by concrete - not a good RF reception environment :slight_smile:. The signal feed is from an outside Yagi antenna (pointed at the tower) to a WeBoost for rebroadcast in the basement (for phones as well as the MAX Transit). Given that path I had expected the two MAX radios to read identically for a given carrier.

My concern is that the two readings might indicate that I should set something up differently. In the meantime, things are working OK, so no trouble ticket is warranted, I think.

(Ordinarily the two radios are set up with different carriers (VZW and AT&T), FWIW.)


#5

Hello @zegor_mjol,
Word of advice, never use a mobile/cellular repeater to feed your mobile/cellular modem.
Part of the reason is that the modems are MIMO, so each antenna needs a separate & clean signal path, mobile boosters can not facilitate this requirement, in actual fact they tend to hamper (interfere with and prevent) good MIMO & true LTE.

Your antennas on the modem need to be in a XPOL layout if you are in a rural environment.

Have a look at these previous threads and the discussion with @Joey_van_der_Gaag and myself, there is some good guidance and examples that may help you.

Depending on which country you are in, there will be a local Peplink Partner that can help you experienced in RF (I’m based in Australia myself). You can also continue to reach out here in the Forum to some of the experienced RF technicians that are members.
Happy to Help,
Marcus :slight_smile:


Exterior antennas and Amplification BR1
#6

Just to add to @mldowling’s reply,

If you do not use a MIMO (2-in-1) antenna or two seperate 4G antennas for each Transit DUO modem, you will not be able to recieve 4G speeds.
As Marcus says, using cellular repeaters will most likely only give you worse results.

My personal advise would be to use a MIMO flatpanel antenna or two directional yagi antennas with a horizontal mounting or 45 degrees polarisation bracket.

MIMO flatpanel antenna:

Directional yagi antennas with one horizontal mounting bracket:


#7

Thanks to both of you for the MIMO explanations (and recommendations) w.r.t. LTE connectivity.

In our case the booster + Yagi antenna do improve the overall speed (the location is quite marginal w.r.t. the tower), but my take-away from the explanations is that we get the benefit of only one channel, that the diversity component is simply not there for our system, due to the single antenna. Is that correct?

Assuming that I have only one coax cable run - anything else I should consider to improve connectivity?

Assuming that I can add a second coax run, but only to a pole about 50 feet or more distant from the first antenna, can one mount a second (diversity) antenna there? Or asked differently, how far apart may the two polarization (±45 degrees) antennas be and still be jointly functional?

FWIW: We are on Verizon and AT&T in the US, connecting on bands 13 and 17 (700 MHz)

I appreciate your patience with me :slight_smile: - RF level network technology has so far been beyond the scope of my core competency.


#8

Hello @zegor_mjol,
With both the information from @Joey_van_der_Gaag and myself, see if you can work through the antenna selection guide from Telco Antennas at https://www.telcoantennas.com.au/site/what-antenna-do-i-need, although it is primarily written for Australia, the fundamentals are the same for anywhere in the world.

You will need to run at least two additional antenna cables (Minimum LMR400 or LCU400 cable).

Use with s suitable high gain antenna setup using antennas like these:
or
or two(2) of

(These antennas can be found here at https://www.telcoantennas.com.au/site/catalog/all-antennas/list-frequency/700mhz

As you have a MAX Transit DUO, you will then need to feed the two antenna feeds into a suitably frequency match RF splitter, this is immediately going to halve your RF signal strength.

Connect your MX Transit DUO using short RF 50Ohm patch leads.

Only use 50Ohm RF Cable and 50Ohm RF splitters, not TV or Consumer Satellite cable or splitters which are 75 Ohm.

I would also highly recommend that you add lightening protection to the antenna feeds, lightening at over 400 meters (1/4 of a mile) can still produces enough energy to damage equipment connected to external antennas. https://www.telcoantennas.com.au/site/catalog/surge-protection

There are partners here (including myself) that can put together all of this as a kit for you to self install if you like. Shipping from Australia can be expensive and take some time, so best to source locally where you are.
Happy to Help,
Marcus :slight_smile:


Need advice before purchase
#9

Very helpful - thanks!

Z


#10

One more question: I have two antenna mounts, each with a 50 Ohm coax cable. However, they are approx. 75 feet apart. Can two antennas (with the ±45 degrees offsets) still be effective, though that far apart?


#11

Hello @zegor_mjol,
The recommendation is to keep the antennas reasonably close when they are phase inverted, when properly installed the phase inverted antennas will not interfere with each other, separating them by 22+ meters (75 feet) does not offer any performance advantage with the frequencies, you may actually reduce the performance advantage of the MIMO equipment especially if you have differing cable lengths, cable types and antenna types, keep all the RF cables the same in length and in quality (such as LMR400 or LCU400 including the connector), this is important where there is low signal to begin with and you are using a MIMO capable solution.
Happy to Help,
Marcus :slight_smile: