LoRa APRS in Slovakia

Hello. Let's talk about LoRa APRS they did not recycle already written texts for the introduction, I recommend spending five minutes on a short introduction from the website: https://www.aprs.cz/lora-jako-ucinny-digitalni-mod-pro-aprs/

LoRa iGate OM7AMA
LoRa iGate OM7AMA

Okay, now that we have the mandatory ride behind us, a question arises, what kind of development of this technology do we have in Slovakia. In our country, several radio amateurs are working on the topic of APRS using LoRa technology, which I could count on the fingers of two hands. Thanks to this, the first installed iGate receivers and APRS Trackers were created.

It is something new and different from the classic APRS 1.2K operating in the VHF band. When deciding whether to go this way, it is always necessary to be aware of all aspects, because everything has its advantages, and also disadvantages.


  • low costs for the condition of iGates and Trackers,
  • efficient data transmission over long distances with low power,
  • energy efficiency,
  • separate device for the purpose of tracking


  • it is necessary to tinker 😊

Of course, more could be written, but when I underline it and calculate it, even a disadvantage can actually be turned into an advantage, because tinkering is basically also part of our hobby. Of course I realize, that not everyone knows, and that is why we are a community, to help each other. This article is also the result and goal of this, to get basic and necessary information among other radio amateurs, on the basis of which almost everyone will be able to make their own tracker, possibly install iGate, which would help us expand the APRS network.

iGate as such

LoRa APRS Tracker bike
LoRa APRS Tracker bike

So that we don't start from the end, I'll start with an element, which forms a network, and that's iGats. As always, there are several solutions to choose from, but our choice settled on using the TTGO LoRa32 board. You can buy it via AliExpress and here is a link where you can find all the technical parametershttps://www.aliexpress.com/…list_main.426.30311802JBqaFt Today the price tag is approx 20 euros.

You can find the FW for iGate at: https://github.com/lora-aprs/LoRa_APRS_iGate?fb…edEmIgMqvNmBZzc

iGate needs power for its proper function, UHF antenna for receiving signals and WIFI connection. After configuring and connecting the power, the iGate will connect to your WIFI and the site map www.aprs.fi the LoRa iGat symbol will appear. You define the position on the map by entering your coordinates when configuring the board. The receivers are able to process even very weak signals, but yes of course, the better the position, the better the coverage. But don't worry, the iGate located on a housing estate in the city is also better, like none. Our common goal is, so that we can find enough of you in Slovakia and build a network of receivers together, which would allow us quality coverage. To date, I have registered on the iGata map in these regions: Košice city, Kojšovská hoľa, Brezno, Lower Kubin, Banska Bystrica, Man's work, Lower Ohio, Bratislava. If I forgot someone, I apologize in advance. We thank you all for the development of the APRS network. That's great, but we still have places not covered and this is a challenge for all of you, to join us and help us with this project. The best places are of course the high stakes, but where there is no height, density will help, thus, if there are more of us, the network will expand and the coverage map will be colored. Together we can do it.

Everything worked out, we have a network and what's next?

Of course, without end devices, the network has no meaning, and therefore different constructions of APRS trackers were also gradually created. They are single purpose devices only for sending location and sending message. That's why I liked this idea, because during the hike, SOTE, na portably, or on mushrooms, I don't have to allocate and discharge another radio station separately on APRS. I have it on hand, and if I don't go to CQ I wait, will someone call me. My tracker reports in the message, that I am in the field and where I am QRV. I just turn on the tracker, I put it in my backpack, cars, on a bike and I don't care. The device works by itself without my intervention and I can devote myself to other activities.

I'm ours?

LoRa APRS Tracker ASR6502

As with iGats, also for trackers there are several development boards to choose from and after some time and trials we settled on using the CubeCell GPS-6502 ASR6502 board. Here is the link: https://www.aliexpress.com/item/100500267229…Uid=QXM7SuN2ebBT

You can find the FW for the tracker at : https://github.com/dj1an/Cubecell_LoRa_APRS_Tracker?fbclid=IwA…uFGcS6JK-yOLErfw

Today the price tag is approx 30 euros. When the ordered board arrives, the package includes a board, UHF antenna and power cable. That antenna tunes roughly to 470 Mhz, so you save it for something else, but basically you already have most of what you need.  In order for the board to become a functional tracker, it needs to be placed in a box, connect the GPS antenna power supply and the UHF antenna. We handle the boxes differently. From completely universal to storing various objects, to precisely designed and printed by a 3D printer. STL files are available. The GPS antenna is also located on the board, but it worked for us to use an external one connected with an IPX connector, which is there for this purpose. The external antenna has significantly better efficiency. Another component, what you need is a patch cable for connecting the UHF antenna. We also use IPX here (on the board) and on the other hand panel SMA. And finally, just connect the power supply. So when you have successfully assembled and configured the whole thing, the tracker is ready to use. Yes, configuring and uploading the FW is like a flight to space for me, and I always successfully annoy the willing Paľ OM7FX, don't worry write him anything, happy to help. Sister Pali. When you get here, you connect the power supply and after a short start, your brand will appear on the display, profile, battery status, time, the number of satellites and the time of the next track. The tracker now waits until it finds at least three satellites, and when this condition is met, sends the first track. iGate receives your signal and sends it to the aprs.fi server.  After the first broadcast track, your symbol and brand will appear on the map. When you click on it, a window will open, in which you can see the mark, time, signal strength, velocity, battery status, iGatu badge, who received your signal and message, which you set. The FW tracker allows you to choose from three profiles, each of which can have a different symbol, for example a car, bike, or anything that the APRS protocol knows and offers - the choice is large.   Each profile can also be defined specifically, especially regarding the frequency of sending tracks, which are defined either by time, or the conditions for changing your movement (smart beaconing). Of course, you can have a different predefined message for each profile.

LoRa APRS – practical experience

In my case, it is a conversion into a pocket where we went for size, weight and endurance. The tracker is powered by two 3.7V batteries / 400mAh in parallel connection, which is enough for more than 24 hours of operation with a total weight of 84g. The power of the transmitted signal is 100mW and this power can be reduced by setting no, but why 😊. This way it fits in the pocket, or in a bike pocket and the like. The price tag of the finished device, which is in the photo does not exceed the amount 50 eur. Vehicle version. When installing in a car, of course, weight and dimensions are not so important, and thus you can place the device in any box. In vehicles, it is very convenient to use higher power, and in the offer on AliExpress there are available output stages from 1W to 8W. I use PA 1W, which is fine. I made the longest jump with a power of 1W from the tracker to the iGat at a distance 288 km. Of course there are better results. Solution, which I liked, you can see in the photos below the article. Videos are also available, which I uploaded to my YT channel, which you can find on this link: https://youtube.com/@miroslavsnopko3294 On this channel, you will also find a video with a description of the functioning of the tracker of his currency, functions and controls. In the description of the video itself, there are links to order the necessary components. Basically, that should be enough, to put it together and use it yourself. I wish you a pleasant viewing.  Quite comprehensive information can be obtained from the FB group: https://www.facebook.com/groups/3615066025205504 I highly recommend. For these purposes, we have also created our OM group on messenger under the name: APRS / LoRa and everyone is welcome in it. There we take over everything related to production and ideas. We will be happy to answer any questions there.

But good, but what about others who use classic APRS in the VHF band?

LoRa APRS Tracker for the car
LoRa APRS Tracker for the car

Right question. The answer is like that joke, about a woman behind the wheel. She is like a star, You see her, she doesn't see you 😊. That's how it is here too. APRS RPT-re operating in the VHF band, of which there are several in OM, we have set them like this, to forward selected data from the aprs.fi map. Well, at least those two, that we built are set up like this. One is in Poľana and the other above the town of Banská Bystrica. When the LoRa tracker broadcasts its data and it appears on the map, the VHF APRS RPT sends it repeatedly. If you are a classic APRS user, this information will appear on the station after receiving it. Thanks to this setup, at least a partial intersection between the two technologies is created.

Why all this?

You could say why not 😊, but there are also practical reasons. Firstly, who plays doesn't get angry. Everyone will probably be pleased with the device, which he can build from available parts for an affordable price, and what's more, it works well. I use it when traveling by car, when I ride a bike, na huby, and SOTU, or just like that when we go to a meeting. I'm simply letting the target audience know, that I am on the move and in charge, which they will also read, that I am receiving and on what frequency. It all leads to that, to take our hobby somewhere further and make ourselves happy with such toys. Among other things, especially during trips to nature, it is a nice addition in case of any problem. After all, anything can happen. In this spirit, I also addressed the Mountain Service of the Slovak Republic, where a certain cooperation is looming where this technology could also be beneficial, but that's a long way, so I'll talk about that for sometime in the future.

Big thanks

LoRa iGate
LoRa iGate

I saved this for last. I want to specifically thank radio amateurs from Košice Martin OM8KT aTo Peja OM8AKX for helping with our beginnings 😊. I am glad, that people will be found, who are willing to selflessly share advice and experience. Right after them, I also thank our "digital" guru Pal OM7FX and so too To Peja OM7TEK who helped us a lot as a programmer in modifying the first FW.

So, friends, let's do it together and try to develop this network, let's keep our APRS map filled.


We are also preparing a practical presentation at the Remata meeting 2023, Donovaly 2023 and the Tatras 2023 of course, call if you have any questions +421915864250, or write to miro.om7ama@gmail.com

73 on the band and goodbye on the map Miro B.Bystrica / OM7AMA

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1 year ago

For these and similar applications,I recommend checking the trash cans, where they throw away disposable e-cigarettes.
In most disposable e-cigarettes, the LiPol cells are usually 3.7V 400mAh, or in vats “e-cig” are 3.7V 900mAh cells.
They are fully rechargeable and last more than 400 cycles.
It is good to use protective circuits, hotove, where the charging current can also be set, BMS also works, which disconnects the load when the voltage drops, under 2.3V.
You have to work carefully and preferably outside, so that in the event of accidental cutting of the article during disassembly of the e/vaigle, there was no fire when the article was punctured.

I recommend this circuit, to save the article.

If you want to limit the charging current, there is a notorious circuit, where it is enough to change the resistor and the charging current will decrease.
if we use 2 cl. parallel, it doesn't matter even max. charging current around 800mA/1A is still less, as 2C per article

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