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#204113
Hello, I bought 2 sparkfun pro Rf boards and I have been trying to make them work in point-2-point communication, it is working fine at distances up to 1 meters but as soon as the distance increase i stop receiving the messages. I am using 2 UFL antennas operating at 868 MHz ( https://linxtechnologies.com/wp/wp-cont ... -pw-qw.pdf). I tried different frequencies (864 to 868 Mhz) as well as different LoRa parameters (SF, BW, CR) to no avail. I closed the LoRaWAN jumper on the underside of the board for previous tests.
I followed the tutorial to set the 2 boards for the radio communication. When using the lastRSSI function implemented in the RF95 library I receive RSSI of about -85 dB.
I tried to change the antennas with a spare one that I had but it didn't help me either.
I am welcome to any suggestions that you might have.
#204164
Interesting. It sounds like there is either a connection issue with the antennas or possibly the code is not configured correctly. How are you testing the range? Are you using the LoRa WAN Arduino Example example from the Pro RF Hookup Guide? If so, double check you are defining the configuration to the correct frequency in that example since it defaults to 915MHz. If you are just using the Point to Point Arduino Examples, try de-soldering the LoRaWAN jumpers on the back, double-check the frequency setting, and retest.

If that does not work, can you please take a few photos of your boards and attach them to your reply? That may help us identify any other possible hardware issues.
#204175
Hello,
I tried what you mentionned but it didn't resolve my problem. I tried replacing the antennas by wire of good length(86 mm as indicated in the tutorial) and I obtainned a very small increase of range (something like 0.5 meter).
I tried analysing the RSSI with the function lastRSSI available in the RadioHead library and I obtained RSSI ranging from -75 at ~10 cm to -95 at 1 meter(with the wire antennas).

I took some picture of my setup, one of the board is connected to my laptop while the other one is connected to an external battery(I commented the line testing the Serial connection ).
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I kind of messed up when de-soldering the LoRaWAN jumpers on this one.
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The antenna connectors on the boards look all right, as well as the antenna connectors (on the antennas).
#204243
Interesting. Everything in your setup looks okay here so we can rule out a connection issue. Just to confirm, you are setting the frequency by either uncommenting or editing one of these two lines in the Client/Server examples, correct? And you have tried the full band from 863-870MHz?

Is it possible you are testing in an environment that has a lot of RF interference? If you can, try testing in a different place, possibly outdoors, and see if you get any increase in performance here. Finally, when you start seeing the packet loss in between the to Pro RF's, is it a complete loss of data or are you getting intermittent breaks?
#204244
Hello, yes I am uncommenting the line setting the frequency at 864.1 MHz and commenting the one setting it at 915 MHz. I did try different frequencies between 863-870 (3 or 4) and I tried my setup outdoor already so the interferences are not really likely.

Usually I see a complete loss of packet directly related when my 2 boards get a bit too far from each other.

I've read that it is probably caused by faulty hardware, is it possible ?
#204267
I agree, nothing in your setup seems to be the cause of the issue so it is safe to conclude that one or both of the Pro RF boards have an RFM95W module that is not working properly. I think what would be the best option here would be to have one replacement Pro RF sent and you can test it with both to see if you can identify which one is malfunctioning. If you get the same results from both boards, then a second replacement would be the next step.

If you purchased the Pro RF's directly from SparkFun, please fill out the form on this page and in the "Why do you want an RMA?" box, enter a brief description of the issue and link to this thread and we will follow up with further instructions for the RMA process. If you purchased it from one of our Distributors, you will need to contact them directly. Feel free to refer to this forum thread, if necessary. If you have any issues with that process, please send me a Private Message and we can assist you further.
#204361
Ok, so I ordered 2 new boards (to be safe) and started testing with one of them aqnd the old ones. At first I managed to obtain a range of up to ~5 meters with the U.FL antennas once and then I had the same problem as previously (very short range). I then tried the 2 new boards together and I still had the same range issues.
I then replaced the U.FL antennas by wire which didn't solve anything. I will try changing the Frequency into the US frequency to test it out.
Is there anything I should have been careful about when handling the boards (not putting my fingers somewhere in particular, etc...). I always powered the boards through the Micro-USB-B port so I don't think I could have damaged them with a voltage too high.
Do you have some references about the RSSI I am supposed to get at short range with these boards and wire antennas? It would help me identify the source of my problem.
#204372
Well that is just frustrating. My thoughts here are either there is a lot of interference around the 868MHz band where you are testing, the RFM95 is not tuning to the EU 868MHz band effectively or something really weird is happening with that u.Fl antenna causing the antenna line to fail/malfunction (very unlikely). Try testing on 915MHz and a wire antenna and see if that helps anything.

I would need to do some more digging to find some more references for the RSSI you should be getting but as a quick option, take a look through the datasheet for the RFM95 if you have not already. I will talk to our RF pros at SparkFun on Monday and see if they have any insights into what might be causing the issue here.