improve LR XBEE range

Q&A forumCategory: Questionsimprove LR XBEE range
pauloxpto asked 3 weeks ago

Hi, have another question concerning XBEE radios
I have the LR modules with default configuration and, sometimes with dense trees, RTK link is lost in small distances like 300m. Otherwise I can go up to 1500m no problem.
I wonder if it is possible to increase range by decreasing OTA baudrate as in other LORA modules. From base to rover I am only sending 1Hz RTCM messages, something like 2000bps or less. (and Nothing from rover to base)

1 Answers
clive1 answered 3 weeks ago

Surely it needs more than 2000 bits per second?
Have you tried a high-gain antenna on the Rover? Base radio antenna as high above ground a practical?

pauloxpto replied 3 weeks ago

Hi Clive!
Okok, I had my math wrong. Aproximately 1100Bytes every second, That would perfectly work with 38kbs, or even 14kbs rigth? I imagine those xbee come configured with more than that don´t they?
As for the rover antenna, no, have not tried high gain. anyway it has to remain small for hard environment: trees, bushes, accidents.
The base radio antenna is always 5m over ground on open areas

clive1 replied 3 weeks ago

I think I’m sending 2 Hz data via LoRa at around 18.75 kbps
Not sure what the XBee defaults are with regard to power and air-rates. Generally dropping them will get you further. The HM-TRP/SIK radios can use ECC to correct the data, but half the bandwidth. RTCM3 isn’t helped via retry/rebroadcast. I would tend to forego the ECC for a strategy that outputs data faster, with short (air-time) packets, and with extra GPS packets stuffed to improve chance rover has at least a workable set of data.
Not sure of your vehicle application, ours can accommodate a rigid antenna in the 7 dBi range. High gain on a RX only antenna really doesn’t draw any regulatory scrutiny vs ERP