Yesterday, finished with a disappointing result which I blamed on the lack of a GPS antenna for the Heltec CubeCell GPS ASR6502 boards. Today, following the risky, and highly unscientific – “Surely anything can almost be an antenna? Right!?” approach – I went scavenging and cannibalised some old equipment for anything resembling an antenna with an IPEX connector.
The quest for antennae
I had a handheld Garmin Vista E-Trex GPS which I bought in the States maybe 20 years ago. It had been sitting in a box doing nothing, and the batteries had leaked and pretty much wrecked it. I tore that apart this morning looking for an antenna with hopefully an IPEX fitting on the end that I could neatly detach and repurpose. Sadly, that wasn’t to be as the antenna was soldered to the board:
I also have a huge drawer full of old routers and noticed that some of the wifi antenna fittings appeared to have RP-SMA connections on the outside. Opening up an old Billion router I discovered the fittings and antennas could be unscrewed and internally they were attached to a wifi interface via IPEX connectors! These popped off easily and I ended up with this. Perfekt!
A word of warning. I really DON’T recommend you try this at home. I know that incorrect antennas can damage some transmission equipment, but I was prepared to take the chance. These boards are relatively inexpensive and I had a spare so I was prepared to take a chance – for science. 😉
On the road again
With my Heltec ‘HeliumACTMapper2‘ now sporting a *cough* wifi antenna *cough* attached to the GPS(!), I headed back out to the hotspot hunting ground.
The Mapper quickly switched from ‘Joining‘ to ‘Joined‘ and then ‘GPS Searching’ – again connecting via Generous Wooden Loris. And I waited…
Three green hexes!
And there is was! It got a satellite lock and the Mapper sent a data packet which showed up in Helium’s Cargo just a few moments later. The dodgy antenna had worked, and information was now been captured every X minutes and being sent through the decoder and written to Cargo and Mapper as it should. Winner!
From here, the mapper captured the GPS data and attempted to send it every few minutes. It didn’t always have a hotspot in proximity and so the send wasn’t always successful, but it was doing what it should and I was pretty chuffed.
Here’s a terrible shot of the GPS telemetry which pops up briefly from time to time when it sends – the shutter speed and refresh rate of the OLED display were out of sync.
Today I learned that…
- Maybe something that looks like an antenna CAN indeed serve as a GPS antenna 😉
- Once I got satellite lock, and data could be sent, that confirmed that ALL of my Helium Console configuration worked! I’ll finish the post about that now I know it works.
- The code for the Mapper doesn’t appear to try and get a satellite lock UNTIL it has first been able to join a hotspot – after that it it just keeps capturing data and attempting to send it, whether the hotspot is within range or not.
- The Helium network works!
I’m not done
I’m still getting a proper antenna for these – this is just a brief stopgap measure – but, I’m please I managed to get over the hurdles from yesterday. We now have a few hundred metres of Canberra mapped! Pathetic, I know, but sometimes it’s the little things.
If you’re interested, visit Helium Mappers or look at Helium Cargo and zoom in on Canberra. Still no sign of the Crocodile – but I now know where it is located (west of these hexes) and I’ll do a drive by to add to these green blobs very soon.