I have the LGT-92-LI with 1.6.5 firmware and all is fine broadcasting data and I’m seeing everything I require in TTS CE (a.k.a V3).
The range seems pretty limited so I took a look at the insides.
Having openned the case I notice there is an ipex connector on the pcb plus a built-in antenna glued to the case edge which is permanently connected.
However, if I plug in an external antenna (such as in my picture) will the circuit actually use it?
And if so, should I unsolder the internal antenna and disconnect from the pcb?
Obviously I don’t want to leave the RF stage without a load nor do I want to have both antennas enabled concurrently.
Pictures I’ve seen of the alternate LGT-92-AA model typically show an external antenna plus a description that suggests it does not have the charging circuit for the li-on battery.
I did wonder if it also had the ipex deliberately enabled, which made me wonder if it was suitably enabled and usable on the LGT-92-LI model (as most users probably wouldn’t be daft enough to break open the case, unless it happened by accident)
No! The LGT92 LI will not use it. The switchover from internal antenna to the IPEX-connector is done by removing R35 and installing R36. This are 0Ohm resistors.
Thanks @wolfp - much appreciated.
I did suspect, just by simple observation, that the external antenna was not being used.
I have more confidence now about making the hardware modification knowing that I can reduce my spread factor and get better range with the external antenna.
Regards - Howard
Will an external antenna make much of a difference in terms of range back to a gateway? I am working on a small project to install one of these on my bike, and the places I ride will fall in and out of range, so I am curious to know if this range is able to be extended with an external antenna? I am quite new to the technology, so I am currently waiting for my unit to arrive in the mail and start experimenting
The antennas of the node and the gateway and their positions are the most important parts concerning the range you can achieve.
There are some discussions in this forum concerning antennas and coverage.
A couple of initial disappointments I had with my own LGT-92-LI were:
a) the GPS fix reliability when using the device hanging on a lanyard and generally walking around outside; and
b) the apparent lack of range when I walking any distance away from my local gateway.
I have to say that making the effort to enable the socket for an external antenna is well worth it.
I coupled a simple -2.3dBi dipole (actually a Wurth Elektronik Hyperion-II) with mag mount to the car and ensured that the LGT-92 was kept horizontal in the vehicle and close to a window.
The usable range immediately increased to several Km instead a few 10s of metres and GPS fix so much better!
But for mapping purposes I get the impression that the range is always going to be less than my preferred RAK811 LoRa module controlled by a Micro:Bit, though admitedly that is more power hungry and does not have GPS. So instead I use ttn-mapper with a mobile phone and a Bad Elf GPS Pro to get a decent location fix.
With the same antenna I’ve easily reached 18km and in all cases using SF7 with ABP.
Not sure if the lower range of the LGT-92 compared to RAK811 is due to less RF power or just my general clumsiness with soldering when I adapted the former device to have an external antenna
This sounds like it might be coverage issue? I am very new to this, but my LGT-92 gets regular hits from nearly 50kms away. I live in a built up area (minimal high rises) but there’s exactly zero line of sight to the gateways I’m hitting.
Wow @slim_pickins I’m impressed you manged to hit gateways nearly 50Kms away from an LGT-92
The gateways must be well sited and possibly at high elevation.
I wonder if you are getting reflections due to buildings in built up area, possibly true as you mention that you don’t have line-of-sight.
Did you use an external antenna with your LGT-92? I found it really improved my own coverage but I limit myself to SF7 to minimise the airtime (and anyway that makes the result more realistic on ttn-mapper when I track my coverage).
How about ~72Km (note multiple hits with same device) from around the Levant Mine area & near Pandeem Lighthouse area back up to one of Rob’s @Verfacil gateways over at Wadebridge, Cornwall, UK, 3 or 4 weeks back Mix of SF7, SF9 & SF12 IIRC - sadly forgot to capture the metadata and details as was on vac!
