# HAB2 High Altitude Balloon Tracker RFM9x Bare PCB - $1.75 ### Help Support The Rocketry Forum: #### Winston ##### Lorenzo von Matterhorn HAB2 High Altitude Balloon Tracker RFM9x Bare PCB -$1.75

This is a board intended to be used as a low component count high altitude balloon tracker using LoRa.

Instructions and software:

https://github.com/StuartsProjects/Devices/tree/master/HAB2 Tracker RFM9x

The
board uses a Hope RFM9x LoRa module and an Arduino Pro Mini (must be the 3.3V 8Mhz version) and a Ublox MAXM8Q GPS.

This is a board only, the RFM9x, Arduino Pro Mini and Ublox MAXM8Q GPS. are not supplied. The 2mm pin headers for fitting the RFM9x are supplied.

The completed tracker will transmits its location using the GPS co-ordinates and will be received over hundreds of kilometres when at altitudes above 2km or so. The tracker sends the tracker payload as FSK RTTY as well as LoRa so can be received with standard amateur radio equipment or a PC and SDR combination. The tracker also puts out a very long range location only packet, which is useful for searching for the landed balloon.

When built following the instructions 'HAB2 Minimum Parts Tracker Build.pdf' the tracker when powered by two AAA lithium energizer batteries has an all up weight of circa 20g and is thus suitable for use with low cost foil party balloons filled with helium.

There is sample balloon tracker software in the \examples folder of the at the documentation link. Other tracker software can be found at the SX12xx-LoRa library here:

The original code and instructions for the tracker PCB using a previous LoRa library is to be found here:

#### SparkyVTFlyer

##### Senior Member
TRF Supporter
This is a neat little project, but really only applies to those with a ham license. The code is not written to do FHSS, which is required by the FCC in the US license free 915MHz ISM band. Thus, to use it as-is, you'd need to install the RMF98 or RFM96 radio and use the 433MHz ham band. Otherwise you cannot use the RFM95 and ISM band without adding FHSS capability.

I recently coded up an FHSS scheme and am still working out the kinks. My ham system got a 99% packet capture rate, but the 915MHz FHSS system only captured about 72% of the packets. I'm still trying to find out why, but there's a lot of possible reasons.

#### jderimig

This is a neat little project, but really only applies to those with a ham license. The code is not written to do FHSS, which is required by the FCC in the US license free 915MHz ISM band. Thus, to use it as-is, you'd need to install the RMF98 or RFM96 radio and use the 433MHz ham band. Otherwise you cannot use the RFM95 and ISM band without adding FHSS capability.

I recently coded up an FHSS scheme and am still working out the kinks. My ham system got a 99% packet capture rate, but the 915MHz FHSS system only captured about 72% of the packets. I'm still trying to find out why, but there's a lot of possible reasons.
If you're a ham you don't need to use FHSS at 900Mhz do you?

#### SparkyVTFlyer

##### Senior Member
TRF Supporter
If you're a ham you don't need to use FHSS at 900Mhz do you?
I’m pretty sure anyone using the 915MHz ISM band is required to use FHSS along with some other restrictions in order to use power above -2dBM. 915MHz isn’t part of the amateur radio band IIRC.

I’d love for someone to prove me wrong on this. My FHSS scheme showed a 28% packet loss rate to n my last attempt. Ouch.

#### jderimig

I’m pretty sure anyone using the 915MHz ISM band is required to use FHSS along with some other restrictions in order to use power above -2dBM. 915MHz isn’t part of the amateur radio band IIRC.

I’d love for someone to prove me wrong on this. My FHSS scheme showed a 28% packet loss rate to n my last attempt. Ouch.
I have looked since you posted this and I haven't found anything on ARRL or Part97where hams are required to use FHSS on 900mhz. There is nothing in Part97 restricting amateur use or modes. Amateurs just have to accept interference from all the license free FHSS transmissions that fill the band in populated areas

Also US hams in ITU region 2 (Americas) can use the entire 902-928Mhz.

#### Winston

##### Lorenzo von Matterhorn
This is a neat little project, but really only applies to those with a ham license.
Free Technician Class study guides:

#### SparkyVTFlyer

##### Senior Member
TRF Supporter
Thats great, thanks guys. I'm still messing around with FHSS since thats still required if you don't have a technician license, correct? I got my technicians a while ago, and will need to renew in the next year or so.