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Portable SOTA APRS I-Gate


#1

I just wanted to let you all know about my recent project regarding SOTA and APRS. As some of you may know I use APRS a lot, also on my SOTA activations. Due to the mountainous topography in my area there are quite a lot spots where it is almost impossible to get a packet out into the APRS-Network.

So I decided to build myself a portable APRS I-Gate that is listening for my (and other) APRS-Packets in my car during my hikes … so I got myself a Raspberry Pi 3. As I was not familiar with RPi and Linux so far I had to do some research, reading and learning! I’m still far from calling myself an expert, but I managed to set up an APRS I-Gate in a rather short period of time.

As APRS-Software for my RPi3 I chose “DireWolf”, it can be found here:

Some helpful links for setting up DireWolf on a Raspberry Pi:

http://qso365.co.uk/2017/02/a-guide-to-setting-up-an-aprs-receive-only-igate-using-a-raspberry-pi-and-an-rtl-sdr-dongle/
http://qso365.co.uk/2017/02/setting-up-an-aprs-rx-only-igate-using-a-raspberry-pi-and-a-pre-built-image/
https://github.com/wb2osz/direwolf/blob/master/doc/User-Guide.pdf

First I tried to setup the system with an RTL-SDR-Dongle, but the SDR was very deaf and did not decode very much of the packets. So I replaced the SDR with my old Kenwood-Handheld, which I have not used for some years now. The results were a lot better, had the system running for some days at home connected to my WLAN and it worked very good and stable.

The next step was to get the system to work in portable mode. I decided to get myself a small portable WLAN-Router by TP-LINK and a prepaid sim card:

Yesterday I tested the setup for the first time on a hike to a local summit (NO SOTA REF.). At the parking lot I connected the whole system together and started the hike. The results were great, no packet was lost during my three hours walk:

http://aprs.fi/#!mt=osm&z=15&ts=1489363200&te=1489419600&call=a%2FOE5REO-7

The next step will be to mount the RPi3 into the car, connect the audiocable with my existing vhf-radio in the car and fit everything together so that the I-Gate can easily be switched on.

I hope that some of you will follow me on my SOTA/APRS hikes in the future!

73 Martin, OE5REO


#2

Great project Martin, congrats.

Peter
OE5AUL


#3

Nice Project. Didn’t you find any packet loss between RPi and TH-D72e? de Wolf, OE7FTJ


#4

hello wolf,

i have not checked every single packets for data loss … all i can say is that the i-gate works fine for me and almost all of my packets were shown on http://aprs.fi/ afterwards. on my last hike on wednesday i switched my handheld to 50mW on my walk down from OE/OO-075 because the battery was nearly empty. even then a lot of packets were received and gated to the internet!

73 martin, oe5reo


#5

Hi Martin,

Great idea!

I have had a similar problem here in VK due to the mountains and sparse digipeater infrastructure. I went down a very similar path to you and also built a digipeater with a RPi3. In my case it’s interfaced to both a VHF and HF radio in my car and has worked very well in some more remote locations (where the HF radio has been the most effective way of getting packets through). If you are interested, I’ve written it up in my blog: http://vk3il.net/projects/raspberry-pi-based-aprs-trackerdigipeaterigate/

73

David
VK3IL


#6

For lazy bones like me, the off the shelf solution is http://www.crosscountrywireless.net/aprs_tnc.htm along with a mobile phone running http://www.crosscountrywireless.net/aprs_messenger_android.html
Jim


#7

Very cool setup. A nice approach to the problem. As another operator suggested, you might look into gating your packets onto HF. It would require a little more construction on the front end, but might save you on data charges in the long run. I’m looking into doing that myself as a future project.
73
Brandon


#8

Surely gating the packets on HF would be the perfect solution. But i do not have a HF radio in my car, so this is (so far) no option for me.

Of course my setup only works when mobile internet is available … i have swiched the WLAN router to “2G only”, so it is more likely to get a network also in remote areas. I found a mobile phone provider that only charges the consumed data without any monthly payments or flatrate … so switching on my portable I-Gate for 5 or 6 hours only costs my a few cents.

Just ordered a small usb gps receiver and hope to get it working with my I-Gate. That way it will be possible to send the real position of the I-Gate without having to edit the configuration file on my Raspberry Pi.


#9

Some progress on my SOTA APRS I-Gate …

Today I received my new GPS-USB Receiver via mail from Hongkong. It was about EUR 6,-- including shipping and it works great on my Raspberry Pi.

So from now on the real position of my I-Gate should be visible on APRS.fi! Will give it a try tomorrow on my activation of OE/OO-356

73 Martin, OE5REO


#10

worked fine today :smile: