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Thread: Super cheap and easy APRS U2APRS smarphone based I-Gate!

  1. #1
    4x4 Ham Member
    Join Date
    Oct 2014
    Western Oregon

    Super cheap and easy APRS U2APRS smarphone based I-Gate!

    A lot of folks on here use APRS 2m VHF. It's a great tool but here never seems to be enough I-Gates or digipeaters. Both can be expensive and hard to build but NOT anymore! Meet the K7POC Phone-Gate! Put up a couple in your home town. Feel free to post this info all over. Let's improve the APRS network!

    How to build a U2APRS smart-phone based receive only APRS I-Gate.

    1. Smart-phone capable of running U2APRS app and using the BaoFeng Tech BTECH APRS-K2 TRRS / APRS Cable.
    2. BTECH APRS cable itself or a home made cable.
    3. A vhf radio with uv-5r type mic/speaker ports.
    4. Connection to a Wifi network
    (Disregard speaker/mic plug type and phone cable compatibility requirement if you are building your own custom cable)

    The brand of radio dose not matter but it needs to have uv-5r type mic/speaker ports. A simple and cheap uv-5r works fine. Use the best antenna you can and get it as high as you can. If on a budget a J-pole hung from a tree branch works fine.

    Download the APP from here

    Please note these settings are what I am currently using many of them are simply personal preferences. Numbers 1, 2, 4 and 29-31 are very important to get right. It took me quite a wile to get these settings correct. If you find that a listed setting is wrong LET ME KNOW!

    After installing the app go into the settings.

    U2APRS settings.
    1. Enter your call sign with a dash one after it with no spaces Example x7xx-1
    2. Select your “Station symbol” as I& I--Gate
    3. Turn “Use APRS Symbol” On.
    4. Set “Position source” to GPS
    5. Set “Beacon interval” to your own preference. Mine is set at 600 seconds.
    6. “Traveling distance” to 1000
    7. Set “Turn angle” to zero.
    8. Set “Minimum beacon interval” to 120
    9. Set “Ambiguity” to your own preference. Mine is turned off.
    10. Set “GPS on demand” to off.
    11. “Search on start” should say ON.
    12. “GPS search time” should be 10.
    13. “Direction change” should be zero.
    14. Set “comment” to your preference. I like to just use “U2APRS smart phone RX only I-gate”
    15. I currently have nothing in “Friend List” setting
    16. Set “Sensor operation” to off.
    17. “Voice notice” should be off
    18. “Vibrate” should be off
    19. “Status bar operation” should be off.
    20. “Notification only in foreground” should be off.
    21. “Monitoring messages” need to be set to “Me”
    22. Turn “Auto message tab” on.
    23. “Vibration on receive” set to off.
    24. “Voice synthesis” should be On.
    25. “Voice reconstruction” should be On.
    26. “Automatic reply” set to off.
    27. “Show message ack” should not have a green check mark. It should be off.
    28. Set “Status bar notification” to on.
    29. Set “Protocol” to TCP
    30. Set “Server address (TCP)” TO (very important to get this one right)
    31. Set “Server port (TCP)” to 10152. (Also a very important setting)
    32. Set “Server address (UDP)” to
    33. Enter your personal APRS passcode.
    34. Set “Login filter” to t/m
    35. Set “show server messages” to off.
    36. Set “Keep screen on” to your preference.
    37. Set “Run as service” to No
    38. Set “hide tab” to No.
    39. Set “Clear cache on exit” to No.
    40. Set “debug mode” to off,

    Make sure you place the phone where it can get/hold a good GPS lock. ( it won't work otherwise) Also check that your phone is connected to Wifi. (I have not tested to see if this setup will work threw a cell phone network. It may or may not) Turn off any noise notifications on it as well. Make sure your radio to phone cable is plugged in and turn on the radio. Set the radio to your desired 2m vhf APRS frequency.
    Then go into the “AFSK” tab on the app. Check “RX” and “I-Gate” Then set your input volume by turning off your squelch and lining up the color bar at the arrow. The static level should be right at the arrow. If you can't get the radio input volume adjusted correctly then “press and hold” “Gain=100/Twist=50/50”. You can then adjust the audio input and tone balance. (If you are using the BaoFeng cable and a Chinese HT you should not haft to adjust these settings.) If using a home built cable or another HT/mobile or scanner you will haft to adjust these settings. Feel free to re-post and share this info. Good luck and have fun! K7POC

  2. #2
    4x4 Ham Member Supporting Member kg7els's Avatar
    Join Date
    Nov 2013
    Phoenix, Arizona, United States
    will the app work in the background? ie - if i'm using backcountry navigator in the foreground, will u2aprs still digipeat in the background?

  3. #3
    4x4 Ham Member
    Join Date
    Oct 2014
    Western Oregon
    I do not know if the app will run in the background. it's free so just download it and see. Also note there is NO APP made currently that will allow you to dig-peat. This app is only an I-gate. I am going to test later to see if it will work threw a cell network and not just wifi. It would be really neat to be able to I-gate stations in from my mobile!


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