LoRa/RFM95 - Testing long range PHY settings - Findings

[cloolalang]

Re: Any success story on LoRa(RFM95) module and MySensors?

I have been testing out the RA-02 433MHz Lora modules with the Mysensors implementation.
I setup a GPS node, reporting through the RFM95-MQTT gateway to Hassio.. All good it works well.

I hope to eventually run two Mysensors LoRa gateways, 1 local, high speed and with multiple nodes, and another, so-called long-range mode gateway for remote sensors or GPS tracking.

So I thought I would try some other Lora Phy settings in the hope to get better range between the mobile GPS node in my car and the gateway at home.

I am using BW 62.5KHz, CRC Coding 4/5, Spreading factor 2048CPS (SF11).
Messages can take up to 4 seconds long time on air.

I tried SF12 (4096CPS) and it doesn't completely work, for some reason some presentation messages fail (NACK) such as the internal presentation version message: (2.3.2).

I tried increasing the time-out setting, but It didnt really work, Im wondering is these long time-on-air messages are causing other time-out issues somewhere or perhaps certain payloads is causing issues.??

Other settings:
In Sketches:
#define MY_RFM95_ATC_MODE_DISABLED

In RFM95.h
RX_PAYLOAD_CRC_ON
RFM95_AGC_AUTO_ON
RFM95_LOW_DATA_RATE_OPTIMIZE
RFM95_RETRY_TIMEOUT_MS (3000ul)

In MyTransport.h
#define MY_TRANSPORT_STATE_TIMEOUT_MS (4*1000ul)

I would be very interested in your comments
P

[mfalkvidd]

@cloolalang if you haven't seen it already, https://forum.mysensors.org/topic/8813/any-success-story-on-lora-rfm95-module-and-mysensors/ might have some good information.

Edit: sorry, I see now that you already linked to that thread. Feel free to ignore this post.

[cloolalang]

Thanks for taking a look Mikeal,.
Here's my update:

1. I added a 47uF cap to the 3.3V input to the RA-01 Lora radios on both Node and Gateway, now the SF 12 long payload messages pass!

2. I tested various SF and BW and coding rates, I decided on the following for the "long-range mode". Typical use will be point-point mode, or gateway to 2 or 3 nodes max, no repeaters. Horizontal polarised yagi antennas.

• MY_RFM95_FREQUENCY 433237500ul (its 1MHz away from my co-located standard mode gateway frequency and other local ISM users).

• RFM95_MODEM_CONFIGRUATION RFM95_BW62_5CR45SF4096 (Typical time-on-air is around 4000ms.

• MY_RFM95_ATC_MODE_DISABLED (to reduce traffic).

• MY_RFM95_TX_POWER_DBM 23.

• MY_RFM95_MAX_POWER_LEVEL_DBM 23u.

• RFM95_RETRY_TIMEOUT_MS 3000ul.

• MY_TRANSPORT_STATE_TIMEOUT_MS 6*1000ul.

• Passive mode = off.

• MY_REPEATER_FEATURE = off.

• AGC_AUTO_ON

• RX_PAYLOAD_CRC_ON

• LOW_DATA_RATE_OPTIMIZE.

• CAD = Default settings.

• Encrypton = Off

• Signing = Off

• Sleep = Off.

Further test planned:

1. 866 MHz setup.
2. TXCO setup narrow band modes to 7.6KHz
3. Chain network topology with repeaters.
4. Higher RF power (Ham radio license).

Cheers
P

[FarmerEd]

@cloolalang said in LoRa/RFM95 - Testing long range PHY settings - Findings:

w the SF 12 long payload messages pass!

I tested various SF and BW and coding rates, I decided on the following for the "long-range mode". Typical use will be point-point mode, or gateway to 2 or 3 nodes max, no repeaters. Horizontal polarised yagi antennas.

MY_RFM95_FREQUENCY 433237500ul (its 1MHz away from my co-located standard mode gateway frequency and other local ISM users).

RFM95_MODEM_CONFIGRUATION RFM95_BW62_5CR45SF4096 (Typical time-on-air is around 4000ms.

MY_RFM95_ATC_MODE_DISABLED (to reduce traffic).

How is testing going on this?
I'm interested to know what sort of distance you can cover, I'm planning on some long range sensors to be deployed on my farm. I'm not quite gettting the range I would like.

Here is the radio config in my current setup, but I will definitly look at some of the additional config that you have.

#define MY_RFM95_FREQUENCY (RFM95_868MHZ)
#define MY_RFM95_MAX_POWER_LEVEL_DBM (100) 
#define MY_TRANSPORT_STATE_TIMEOUT_MS  (3*1000ul)
#define RFM95_RETRY_TIMEOUT_MS  (3000ul) 
#define MY_RFM95_MODEM_CONFIGRUATION  RFM95_BW125CR48SF4096

As a matter of interest has anyone used repeater nodes with these sort of long range setups. I'm talking about distances over a KM with no clear line of sight. I've managed to get simple comunications working over the required distance using simple transmitter and receiver sketches (provided by heltec, to demonstrate their Lora Node) sending "hello" packets