Max Transit Cat 18: Same signal with 2x high gain antennas and 2x stock antennas vs 4x stock antennas

I have a MAX Transit Cat 18. Here’s what I’m getting with 4x stock antennas all on Verizon.

I then swapped out both Main 1A and Main 1B antennas to use two Wilson weBoost High Gain LPDA Antenna - 311228 antennas. The signal tanked so far that I got 0.67 Mbps down and it errored on upload. Does anyone know why this is happening? Is it possible that the mismatch of stock and high gain antennas is causing this to happen? Do I have to have 4 of exactly the same antenna to work?

PS: I also have two Wilson Pro IoT 5-Band direct connect amplifiers. I tried putting them on the two high gain antennas and I get a similar result.

What were the signal readings with those massive high gain antennas connected?

Too much again - where RF noise is also amplified and drowns out the usable signal is a thing.

Also Which ports did you have connected? You’ want to put the wilsons on Main1A & Aux 1A as a pair or Main1B and Aux 1B.

Okay I just did three tests to give you a better idea of the numbers for each setup. It seems my signal strength and speed tests do fluctuate so there’s a little grain of salt with these numbers but they do give the general idea.

  • TEST 1: Stock antennas
  • TEST 2: LDPA antennas on Main 1A & Main 1B, stock antennas on Aux 1A & Aux 1B
  • TEST 3: LDPA antennas on Main 1A & Aux 1A, stock antennas on Main 1B & Aux 1B

Do you know which way the signal strength is calculated?

  • Signal strength is reported as the strongest signal of all four antennas
  • Signal strength is reported as the average signals of all four antennas
  • Something else

Not sure if it is a reporting issue on the Peplink but the 0dB SiNR for the secondary band in all your screenshots is probably something to look into (although I note you had better readings from the initial post with the stock antennas).

As Martin points out in his response antenna gain is a two way street, it’s all very well slapping a high gain antenna on a radio but you will also then hear the noise around you much easier - this is somewhat evident in the fact you are seeing a higher RSSI but a worse SINR value with the high gain antennas in use.

Out of interest how long are the cables between the antennas and the Peplink and what kind of cable are you using, have you checked that all the terminations are good?

Do you also know roughly how far you are from the cell tower you are aiming at?

Firstly, get off Band 13. This is the worst performing band in almost all cases, rural and urban. Check to see if the Verizon towers in your area support band 66 and point your antennas in the direction of this tower - your router will aggregate 66 well and with good performance. I turn off Bands 5 and 13 in my rural location. They are both dogs.

Since I see that your router is aggregating your LTE signals, either mount both of your antennas together, but 45 degrees juxtaposed (you can buy a bracket that does this), or mount one over (better than beside each other) the other with a couple feet of separation.

I would test one antenna at a time to see if they are performing alike. Then I would take the steps above to see the results. Like all have said, the high gain can be a problem if your antennas and cabling are not setup properly and with some isolation.

I’ve purchased and tried dipoles, Yagis, setup in MIMO config, and have found that a directional MIMO antenna like the one linked works just as well and has more margin for error in setup (wider profile). You might want to check it out.

Just two cents.

1 Like

And really for Cat18 LTE you should be using the same antenna type / gain across all 4 elements.

Trying to come up with a suitable analogy but imagine having a hearing aid in your left ear cranked up to maximum and then shoving a load of wax in your right ear? :slight_smile:

Panorama do some 4x4 LTE all in ones, I’ve only used theise in the vehicle mount omni format but had good results for them, Taoglas also have some 4 element LTE panel antennas too.

1 Like

Thanks for clarifying the 4x4 MIMO requirement. I’m still stuck in 2x2 with the cat 12. :frowning:

The more gain an antenna has the more directional it is. A 0db antenna picks up equally in all directions, anything higher than 0 has some direction component. Your antenna are obviously very directional antennas that require pointing at specific towers.

A normal omni antenna is typically directional such that it picks up more of a disk instead of a sphere so its not good at above or below but has positive gain on the sides where the horizon typically is and where towers normally are. An omni can pickup multiple different towers in different directions.

You may be pointing those directionals at an overloaded tower or one they don’t want you on at the time, while the normal omni’s can get to a better tower maybe with lower signal strength but more backhaul or other factors. My dad use 2x MIMO directionals with ATT in a rural setting and he ends up having to repoint to different towers once in a while as one will go out or slow down and the other will be fine.

SNR is many times more important the raw signal strength, as mentioned the SNR of 0 is not good maybe your directionally picking up a noise source on that band better than the tower.

In my testing with both WiFi and my 8800L mixing antennas is fine as is doing only 2 out of 4. My 8800L seem to consistently perform better with my 2X external antenna than its 4x internals. I have my WiFi split 1x external 2x internal from my SOHO seems to be no downside while getting better external wifi. Typically transmit is not MIMO so one antenna will be doing upload would be nice to know which one. Ideally you have all 4 antennas as close to modem as possible (minimize cable run) with antennas as high as possible which is why domes with modems on roof with antennas work so well.

Amps amplify signal and noise and add their own noise, so not normally a good thing for receive / download unless they are close to antenna and you have a long run back to modem otherwise they can hurt receive. They can boost transmit though up to 1 watt but a Firstnet modem can do that too, not sure if Peplinks do that.