Parts / Assembly - Locator
Ground based tracking is the essence of successful recovery. So long as we know where our payload is once it lands we should have a successful launch. Over at the shop, you can buy an SMS based locator. Here is a quick description of how to use it. Make sure you’re familiar with it before launch day!
FITTING THE BATTERY AND SIM CARD
You’ll need to get a pre-paid sim card for your country (on whichever network you trust the most – ask over in the Forum if not sure) and you need to know it’s phone number! Flick the catch, lift the battery out and install the sim card as above. Couldn’t be simpler! Charging can take up to 12 hours for the first charge and then around 3-5hrs for future charges. Try to leave it charging for this long (even if it tells you it’s full!)
The GPS unit can take up to a minute or two to get an initial satellite fix outdoors (and indoors often won’t get a fix). It can also take some time to initially find mobile network coverage. The green light on the side will blink once every 3 seconds when mobile network coverage is achieved and double blink when GPS lock has been established.
To locate the device, simply call the number of the sim card and the locator will send an sms with location coordinates. The Google maps link will take you directly to the location.
Be aware that on some mobile versions of Google maps, the coordinates appear as the nearest road. On a computer browser, a green arrow will show the precise coordinates location.
TIPS AND TRICKS
Some places don’t have good mobile network coverage (and some have none at all!). For our flights we often use two SMS trackers to increase our odds of landing in good network coverage. The extra weight is offset with peace of mind!
When you call the tracker, if it has coverage, it will ring 3 times and then hang up. It will then send an SMS with coordinates. You will get straight to voicemail if it is out of coverage. Check that you’re predictions are likely to land you in an area of coverage in advance. In the USA you can use this tool to check for coverage.
Mobile phone networks don’t reach very high! You’ll need to wait until the payload lands before you know exactly where it is. We normally go to the predicted landing site whilst the balloon is in the air and then wait for the tracker to respond to calls.
The most common problem people experience is from the unit failing to connect to a cellular network and/or return a text message. The most frequent cause of this is that the SIM card has not been activated or used within a mobile handset. Although credit can be added and the SIM remotely activated online, the SIM will need to be placed within a mobile handset and used before being introduced into the tracking unit. It is good practice to make and receive a call from the mobile handset before making the exchange. This appears to have the effect of notifying the carrier that the SIM is now in use and allowing full activation of the card.