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dmc271

join:2008-09-02
Stillwater, OK

MIMO with two antennas (UML290 and VL600)

Over the last year, I've had a chance to do extensive testing with the use of two antennas with the UML290 and VL600 modems. Both of these modems have two antenna ports that can be used simultaneously with two antennae to take advantage of MIMO in 4G LTE areas. I thought I'd share some results.

Here's my outside setup (two homemade yagis):




Here's the inside setup (for the UML290):




I used two pre-existing runs of RG6, which performs quite well, despite the impedance mismatch.

And, here are some representative results taken about seven months ago:




With MIMO, I can literally max-out the tower sector (36 Mbps in my area) during off-peak hours when the sector is empty. The typical speeds have unfortunately dropped (by 30-40%) over the last six months due to Verizon 4G slowing down overall, but the top speeds remain the same. For reference, I'm about 4-5 miles from the tower, in a slight valley, some trees around.

This is a relatively inexpensive way to increase speeds. If you already have one external antenna, it's easy to mount a second.


Jim_in_VA

join:2004-07-11
Cobbs Creek, VA
kudos:4

nice setup


dmc271

join:2008-09-02
Stillwater, OK

said by Jim_in_VA:

nice setup

Thanks Jim. After reading your site, my next project is a pair of 760 MHz grids.

pioneer56

join:2008-03-21
Michigan
Reviews:
·Verizon Wireless..
reply to dmc271

Nice setup, thanks for that! I didn't even know I had two ports on my UML290! That's cool. I need another adapter and antenna to see if I can do better. I have pulled 40mbps down and 25up on my phone outside, but we have a metal roof and I see a max of about 25mbps down and 12up on the inside.


dmc271

join:2008-09-02
Stillwater, OK

said by pioneer56:

Nice setup, thanks for that! I didn't even know I had two ports on my UML290! That's cool.

Thanks for the note. Your location sounds like it has great speeds already! I bet it would do wonders just to move your antenna outside, higher above the metal roof. OTOH, if you're going to mount one antenna, you might as well mount two!

BTW, I've also posted instructions on this forum in the past about how to build your own LTE antenna. In case you missed it: »bcbj.org/antennae/lte_yagi_diy.htm

pioneer56

join:2008-03-21
Michigan
reply to dmc271

Yeah, our tower is just down the road about a mile and almost no trees between us and it. It is also very rural so not many users. Thanks again for the write up!



xrayman

join:2008-12-09
Kansas City
kudos:1
reply to dmc271

dmc271, Nice technical write up. Thanks for taking the time to post it.


dmc271

join:2008-09-02
Stillwater, OK

said by xrayman:

dmc271, Nice technical write up. Thanks for taking the time to post it.

Many thanks for the feedback.

patt2k

join:2009-01-16
kudos:1
Reviews:
·Verizon FiOS
reply to dmc271

dmc271 I don't have wireless as my ISP just have phones through VZW but I was always wondering about those types of antennas,aren't you afraid because of high winds speeds may go down a lot of fall of the roof?

otherwise with those speeds I hope you have Unlimited if not then man your caps will go quick.


dmc271

join:2008-09-02
Stillwater, OK

said by patt2k:

...I was always wondering about those types of antennas,aren't you afraid because of high winds speeds may go down a lot of fall of the roof?

The guy wires on the mast work amazingly well against wind. I used to have a 3 ft WiFi grid antenna on the same mast for years, and it has survived 65+ mph winds. Honestly, though, I do get a little scared during strong storms; nothing is totally immune to Oklahoma's winds!

JeffInDFW

join:2013-07-30
Lewisville, TX
reply to dmc271

I sure hope you can help me! I've been all over the internet trying to find info on MIMO with this USB modem!

My application is mobile (in a truck). I want to use a Verizon USB 4G modem like you have, and use both of its external antenna ports. I also need to use a direct connect amplifier.

MY QUESTION:
What happens to the 2G and 3G signal? If you use both ports for MIMO on 4G, do BOTH of those ports ALSO support the 2G/3G signal?

Secondly, I am also interested in Diversity for 2G/3G if you can shed light on how I can pull that off while also doing MIMO with 4G and the direct connect amplifier.

Thank you SO MUCH for any light you can shed on my problem. I've been digging for a while.....



ThomasinNash

@bellsouth.net

Hey guys, I would also like to know how to have this set-up with a direct connect amp.

I have a direct connect 4g amp for Verizon 4G Lte... Would be interested to see how this would work. Would I use a splitter?


dmc271

join:2008-09-02
Stillwater, OK

said by ThomasinNash :

I have a direct connect 4g amp for Verizon 4G Lte... Would be interested to see how this would work. Would I use a splitter?

You don't want to use a splitter/combiner because the signals from the two antennas must be decorrelated in order to sustain MIMO.

I've never tried using a direct-connect amp with my MIMO setup. My suggestion would be to amplify just one of the signals--perhaps the signal going to the standard antenna port (the one with the satellite icon on the UML290). Since you have an amp, can you try this and report back?

The unknown is whether the amp manipulates the signal in a way that interferes with MIMO. The only way to know is to try. If it works with one amp, then perhaps even two direct-connect amps can work.


ThomasInNash

@bellsouth.net

Thanks for the advice, I'll look into this.

I'm living in a high rise condo on the 4th of 7 floors.

Right now my set-up is as follows:

Wilson Directional Antenna (not yagi) connected to rg58 cable going into the condo. (this is not ideal and is kinda ghetto, but it's working as I test things out).

The reason I have it outside is my dbm goes from -110 to -45.

So, here's another question: Would it be better to get a weatherproof box, put the router and modem in it, and lock it to my balcony? I could still connect to wifi from my place.

But, the condo I live at has tons and tons of wifi routers. I want to avoid interference.

Could there be a better solution here? I know I'm 'thread crapping' so I did post in the general wireless forum too. I was thinking since the balcony has a power outlet I could do ethernet over power to the router and such inside but I'm not sure how this would work.

Thanks guys!



ThomasInNash

@myvzw.com

So I ran some tests the other day....

My best results were without an amp outside on my balcony facing what I think is a tower a few hours away... The amp lowered my dmb to around -15... but my speeds were lower than with no amp...

I have a Wilson 4g sleek and a cellmate 4g direct connect amp..

Best results achieved with 4g panel antenna or yagi and whatever the other antenna was (didn't seem to matter).

I had been looking at lowering dmb w/o noticing internet speeds... So with all thsi said, who offers 4g mimo antennas? i don't want to duct-tape two to my condo's balcony...



ThomasInNash

@myvzw.com

Anyone know of any mimo antennas for Verizon? I would like to buy an all in one solution rather than two panel antennas taped to the windows outside my condo... need something a little cleaner...


JeffInDFW

join:2013-07-30
Lewisville, TX
reply to ThomasInNash

Very interesting, Thomas. So, even though the amplifier gave you a stronger signal it LOST speed. Wow. I wonder if DMC's concern about an amplifier -interfering with the MIMO process- is coming into play here. I WONDER if the correct way would be to run two separate amplifiers. Keep the two streams separate for the full path.

Either way, thank you guys very much for sharing your experiences and opinions. As I continue to work forward on this, I will share what I find here.


dmc271

join:2008-09-02
Stillwater, OK
reply to ThomasInNash

Yes, Thomas, thanks for the update. The important thing to check is the SINR value. Amps will boost the signal, but also boost the noise, so this could be the culprit. To make matters more confusing, going from MIMO to SISO will also manifest as a drop in SINR. So, if you get a chance, can you check the SINR values? You'll have to do a Ctrl+D in VZAM, and then choose Field Test or something like that to see the SINR (unless you're using an older version of VZAM).

Regarding a more compact MIMO antenna, there's nothing affordable that I can recall. You could build two biquad antennas into one package, but it won't look at neat as the two panels. BTW, you should rotate your panel antennas + and - 45 degrees to minimize correlation.

Currently, what are your speed like? Your RSSI looks so good that you could be approaching diminishing gains at this point.



ThomasInNash

@myvzw.com

Speeds are around 10up 10 down.. they change often based on the time and how many people are online...

It's funny, if I'm by a tower here in Nash I'll see speeds like 20mbps down and 15 up...

Right now, I just have the Cellmate omni antenna sold by 3g store hooked up to the amp connected to a mbr95 router with uml290 modem.

With this setup, I have a -14 rssi and a SINR of 7db. W/o amp I think the rssi is around -50 or so.

Probably can't do much better than this... The RSSI I was seeing previously were much higher due to me using a hotspot and wilson sleek...



ThomasInNash

@myvzw.com

Actually at night I can get up to 20mbps if not more... Around 15 mbps on upload.

So I adjusted the dip switches on my Cellphone-Mate CM700V-32 amp and I can now get -8 dBm with a SINR of 6-8. The switches are set for 0 attenuation...

The SINR is kind of low... I'm wondering if it's because my condo complex is filled with wi fi signals?



ThomasInNash

@myvzw.com

Speed tests go from around 20/15 late night to 5/8 right now during hte day... must be oversaturation on the network.

This is with a single omni antenna connected to the amp on the 4th floor balcony of my condo.

I'm thinking of getting another omni and connecting it to the other port on the vl600.

I have wi-fi off on my mbr95 and the amp is far away from the modem and antenna.

Why is my SINR so low?



ThomasInNash

@myvzw.com

Okay, sorry for the rapid posts...

best results achieved with the amp... using all dip switches off for maximum gain on uplink gives me the best upload speeds...

Turning on all switches (32db attenuation) works the best for downlink speed. This gives me a -33 dbm signal, if I turn on all the switches for downlink I'm looking at -8 dbm signal but less speed.

I've noticed no difference in connection speed when directly connected to imac or to my mbr95.


dmc271

join:2008-09-02
Stillwater, OK

I've noticed that the VL600 reports SINR values consistently lower than other 4G LTE devices. I recall during my last batch of tests that the VL600 will show, say, an 8 dB SINR whereas the UML290 will show a 14 dB SINR in the exact same location/setup. But, both modems yielded the same speeds despite the reported SINR differences.

So, I don't think your SINR is too low. But, it could certainly be improved. With MIMO, the highest I've seen the VL600 go up to is about a 20 dB SINR. When this happens, I can max-out the tower section at 36 Mbps.

Unfortunately, like you've noticed, everything depends on tower load. From 8-11pm, my speeds drop to 10-12 Mbps, while from 2-6am, I can hit 25+ Mbps.

Can you try using the two antennas again (no amp), and see how it affects SINR? And, how does it affect speed?



ThomasInNash

@myvzw.com

Honestly, It looks like the tower load is the issue. My speeds at night are much better. I live about a mile from downtown Nashville, so I think the towers may be the issue as we've had problems with slowdown... Some towers I'm literally pulling 1mbps both ways with my iPhone... Yet other towers around the city and suburbs I can literally pull 40mbps+ it's crazy...

We have a rooftop deck facing downtown and I can't even pull 1mbps from it (with my phone) which leads me to believe I'm connecting to an over saturated tower... Yet the other side of my building where I'm at, I'm fine.

Here is my current setup as of this moment. On my balcony on the 4th floor of a condo:

1 panel antenna from Wilson.
1 omni antenna from Cellmate.
Amp turned off.
VL600 connected to MBR95 router.

12:30am:
Ping 46ms. Downspeed: 17.42. Up: 13.
RSSI: -37 dBm. SINR: 4db.

12:43am:
Ping 56ms. Down: 22. Up: 11.32
RSSI: -38dbm SINR: 8db.

12:45am:
Ping: 46ms Down:11 Up: 12
RSSI: -35 SINR: 7

12:46am:
Ping: 52ms: Down: 18 Up: 13.27
RSSI: See above.

Here's the same setup with the cellmate amp turned on (direct connection to the 4g port which is connected to the omni antenna):
The dip switches are turned off so maximum gain for all...

-8 dbm. SINR is 6db.
12:49 - Ping 46ms. Down: 13 Up: 15.
12:52 - Ping 52ms. Down: 13 Up: 15

All dip switches turned ON for downlink, remain off for uplink:
-32dbm. SINR is 6db.
12:55 - 47ms. Down: 20 Up: 13

Dip switches ON for downlink. 1,2,4 for uplink (so 8, 16 - 24 dbm on):
1am - 17down 15 up.

For good measure my iphone 5 also on verizon not connected to wifi or anything... trying same server (Nashville comcast).
1am: 15.5 down. 10up.
15 down, 11up. 4ms ping.

Looks like with amp turned off I'm pulling about a RSSI of -37 dbm with both antennas attached to the 600. I'm not aiming at anything just stuck them on my patio... Plan on buying another cellmate omni rather than the panel antenna... Right now the omni is mounted on a window though I may mount it on the railing if i wasn't afraid it would fall off... and see if that makes things batter.

1:05am:
amp off. same setup.
11/13.
12/9.

1:10am.
amp on. max gain for uplink. none for downlink. -32dbm, sinr 9db.
20/15

sorry for errors just got back from bar.

Ping times may be a little different but quite frankly, it doesn't seem like the results are really too different from my iphone lol...

and they are all over the map it's too difficult to really figure out... like i said earlier on some towers with my phone i'll literally pull like 40mbps on the highway by the tower.

1:10am: amp, all switches off.
13/11
12/13
16/13.

no stability here....
1:13am. All downlink switches on, all uplink off: -32dbm. 7 sinr.
19/12
17/11
21/8.5
21/15
25/11 (iphone 5 - 9/7 - rssi -90)
20/15
20/15

1:19am - all dip switches flipped on.. So 0 gain?
27/16, -33 dbm, 8 sinr.
12/15
27/15
17/14
22/14
1:23am: 28/12

Considering it's 5mhz here in Nashville (I think) I guess 30mbps is max down?

keep in mind amp is attached to omni antenna, panel antenna is attached to 3g port on the vl600.

And one last time with amp off:
130: -48dbm. SINR is 6.
15/6.

Plan on getting my 2nd omni soon... Maybe another amp? I doubt it though.



ThomasInNash

@myvzw.com

Setup a Wilson wide-band yagi antenna outside on my patio.

I actually am getting better speeds without the amp than with it... Still connected thru mbr95.

SINR is 7dbm and SINR is -39.

With the amp (as of now at 2;30) it limits my speeds to the point I do better w/o it. Amp helps on upload though.


dmc271

join:2008-09-02
Stillwater, OK

Thanks for the very detailed update. Very interesting that the amp diminishes speeds. It could also be that signal is so strong that the amp is reducing its gain to combat interfering with the tower.

But, even without the amp, your SINR values seem low. This means that either the antennas aren't properly aimed, and thus MIMO can't be established. Or, you do have a MIMO connection, but the SINR is low due to tower load. Based on my observations, when MIMO is established or when tower traffic is low, SINR should jump to 15+ dB.



ThomasInNash

@myvzw.com

I think it's the tower, I'm almost positive I'm aimed correctly as it's where my signal gets to be the best... With that said, there's probably others closer but I can't reach them because of line of sight...

I'm thinking 'tower load' is an issue...Real late (early morning) my speeds are much much better than during the day... Right now I just have the mbr95/vl660 and a Wilson directional and getting -36 rssi. SINR still though. I did order another yagi but I already feel embarassed enough having this ridiculous setup on my balcony of my condo complex. A girl already asked me if it was my astrology set.



ThomasInNash

@myvzw.com

Hooked up a Mifi hotspot outside and SINR is still quite low... Not much I can do here, it's either the towers around here or the fact this complex has dozens of wifi networks...