LoRa Range problems

[Jose Olvera]

step 2 : RMA request
Hello Brandon (Multitech) , please advise how to ask for an RMA to return this units to Multitech and get …a replacement

Attn name ?
full address ?
RMA number ?

NOTE: see additional commands and responses below

ERROR
AT+RSSI
0, 0, 0, 0

OK
AT+PING
Network Not Joined

[Jim Maricondo]

Hi Andrew,

Just wondering, what GPS module did you use with the mDot? Did you use the stock mbed dev board? I am thinking about doing something similar. My hardware background is a little limited so I am looking for something easy.

Thanks,
-Jim

[Brandon Bayer]

Jose,

Those results only indicate something isn’t configured correctly. It doesn’t mean you have bad hardware. Go ahead and open a support case and someone will help you get things set up.

-Brandon

[Jose Olvera]

step 2 : RMA request
Hello Brandon (Multitech) , please advise how to ask for an RMA to return this units to Multitech and get another working set

NOTE: I would like to send you both : the Gateway (Conduit) and the DEV KIT LoRa

Attn name ?
full address ?
RMA number ?

NOTE: see additional commands and responses below

ERROR
AT+RSSI
0, 0, 0, 0

OK
AT+PING
Network Not Joined

[Darrik Spaude]

I believe the resolution worked out through our Support Portal was:
–Disable (uncheck) “public” in the Conduit’s LoRa configuration since the mDot’s “public network” was set to off. These settings need to match.

[Jose Olvera]

your are correct…after PUBLIC was uncheck … I had success to join network

[Jim Maricondo]

Just to confirm what someone else said anecdotally, it’s preferable to put the Conduit as high up off the ground as possible, and point the antenna facing down, right?

And the receiving antenna should be pointed up?

Just trying to maximize my distance. Right now only getting 100-300m, but the Conduit is in a machine room on 2F maybe about 50m inside the building, and there are multiple other tall buildings surrounding it.

Thanks,
-Jim

[Brandon Bayer]

Jim,

That is correct, except up/down antenna orientation doesn’t matter. The important thing is that they are parallel to each other.

-Brandon

[Jim Maricondo]

Thanks. By the way, just for the record: with SF 10 and max power on both devices, the Conduit placed in a machine room approximately 50m deep inside the building on the second floor with stock antenna, end node with mDot EVB chip antenna, in a dense urban environment, I also have only been able to achieve about 700-800 ft max range. Also there are a lot of dead zones caused by buildings in the way.

I will do some additional tests, including the regular mDot with stock external antenna. However when I tested SNR chip antenna vs external antenna at my desk, SNS was only like 2-5 better with the external antenna.

-Jim

[Brian Wyld]

Hi Brandon,

I just checked back with this forum (was very occupied with ‘stuff’) as re-testing range, and discovered your reply about the bad card issue!!!

I’ll open a support call tomorrow to get that RMA’d. However, this will mean I’m down a gateway in the meantime? How long does it typically take to get the replacement card out?

thanks

Brian

[Brandon Bayer]

Brian,

You should be able to keep your current card until you get the new one, and I think they usually ship within a few days.

-Brandon

[Brian Wyld]

Hi,

Ok, thanks Brandon, I have logged my support case this morning.

Brian

[Jim Maricondo]

Not to beat a dead horse, but is there anything else we can do to improve signal strength besides what has already been mentioned in this thread? Like buy a bigger external antenna for the Conduit?

Thanks,
-Jim

[Brian Wyld]

I received some info earlier this week which included a datasheet for a 9dbi antenna : should be a significant improvement over the usual 3dbi 20cm jobs.

Anyone got any hard data on this?

Brian
“your mileage may vary” seems appropriate here..

[Brian Wyld]

Hola,

Got my replacement gateway lora card today. No problems to replace the old one.

However… not sure how to interpret the results of retesting with AT+PING/AT+RSSI…
—-
at+ping
-15,5.5

OK
at+rssi
-25, -26, -23, -25

OK
—-
This appears to still say that the gateway is seeing the mDot packet better (-15db) than the mDot sees the gateway’s packet (-25db)…. but both have the same antenna, and the mDot is at 20 power, gateway at 26!

ze mdot config:
Tx Frequency: 0
Tx Data Rate: SF_12
Tx Power: 20
Tx Wait: on
Tx Inverted Signal: off
Rx Frequency: 869525000
Rx Data Rate: SF_9
Rx Inverted Signal: on

any ideas?

[Brandon Bayer]

Brian,

Try doing ping then rssi for 15 times in a row and see what the general results are. It’s possible interference or something can skew the result of one reading.

-Brandon

[Brian Wyld]

Ok…. I also unscrewwed and re-screwed the antenna : this boosted the signal from around -13 to -5 (as seen by conduit):
at+ping
-13,7.2
at+rssi
-40, -84, -17, -36

at+ping
-5,6.8
at+rssi
-19, -84, -17, -33

at+ping
-5,6.5
at+rssi
-20, -84, -17, -31

at+ping
-3,7.5
at+rssi
-22, -84, -17, -30
at+ping
-4,7.8
at+rssi
-20, -84, -17, -29

at+ping
-5,6.2
at+rssi
-13, -84, -13, -28

at+ping
-5,6.2
at+rssi
-20, -84, -13, -27

at+ping
-13,9.0
at+rssi
-40, -84, -13, -28

As you can see, the Conduit still ALWAYS see the mdot with a better DB than the other way! Also, the db does seem to change for no apparent reason (the change from -5 to -13 had no change to the physical conditions….)

I also tried without the Conduit’s antenna at all:
AT+PING
-67,8.0
AT+RSSI
-84, -84, -17, -51

Same inversion of the powers…

Not sure what’s going on here….

Brian

[Roman Ploskon]

Hi Brandon,

could you please check my data as well? Thank you very much!

Roman

at+ping
-102,7.8

at+rssi
-97, -113, -97, -104

at+ping
-103,8.8

at+rssi
-108, -113, -97, -105

at+ping
-105,8.5

at+rssi
-108, -113, -97, -105

at+ping
-103,6.0

at+rssi
-97, -113, -97, -104

at+ping
-105,8.2

at+rssi
-114, -114, -97, -105

at+ping
-105,8.0

at+rssi
-97, -114, -97, -104

————————————–
Conduit:
Tx Power (dBm): 26

mDot:
Tx Data Rate: SF_7
Tx Power: 20

[Brandon Bayer]

Brian,

Did you get anything figured out with your situation?

-Brandon

[Brandon Bayer]

Roman,

It looks like yours is probably fine. When did you get the MTAC-LORA card?

-Brandon

[Roman Ploskon]

Brandon,
Purchase order is from 9th of November 2015.
Thanks,
Roman

[Brandon Bayer]

Ok, then yes, your card should be fine as this issue was fixed long before that. If you run into issues, you’re welcome to open a support case.

Take care,
-Brandon

[Brian Wyld]

Hi Brandon,

No, I stil have no idea why the rssi values appear to show that the gateway hears the mdot better than the other way around…

I haven’t retested with the new gateways I received to see if they have the same behaviour…

Brian

[Tom Yantek]

Hi,

I have been having range issues as well. I have the dev kit with the mDot and Conduit and standard accessories (antennas). With the TXP set to 20 and SF_10 on the mDot. I have power set 26 on the Conduit running version mLinux 3.1.0, with AEP version 1.0.33, but I am only seeing approximately 1200 feet, non-LOS.

I performed the tests with the AT commands.

WITH antennas:
at+ping
5,8.8
at+rssi
0,-2,0,-1

WITHOUT antennas:
at+ping
-96,7.8
at+rssi
-96,-96,0,-33

Can you tell me if my module is OK? If it is, what could be the problem? I am in an industrial park with the gateway at my desk. To get the measurements, I placed the mDot in my car and drove further away until packets dropped.

Thanks,
Tom

[Chad Goyette]

Tom,
I have done similar range testing with my mDots (conduit on my desk and drive around with mDots) and have had similar range results as you. The range issue (assuming all else is normal) that you are experiencing is likely due to the conduit being inside your building, and the construction of the building leading to interference. To solve this problem i mounted my conduit outside in a weather rated box with a fiberglass ~5′ omni antenna mounted to the roof of a 30′ building. Range testing now results in approximately 1.5 to 2 miles driving around an urban area.

[Tom Yantek]

Chad,

Thanks for the reply. That was what what I was leaning toward also after swapping out for a few different antennas.

I found a company in San Fran doing some testing where and their gateway and antenna were on a rooftop as well.

Thanks,
Tom

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