Sunday, March 24, 2019

-Raspberry Pi 3 and Mobilinkd TNC2 for APRS duty

  • Setup XASTIR on Raspbian to act as an Igate using Mobilinkd KISS TNC.

XASTIR doing RF -> inet gating.  Terminal highlights commands to activate Bluetooth serial link after paired to Mobilinkd.

Update 6/2020 - Have been running an APRS Igate KL3RR-2 for about 1.5 years. Initially had some issues with bluetooth stability on the Raspi3.  The BT link would fail after a few weeks. I found this was a known issue and solved in the Raspi3 B. Indeed it fixed the problem and now has run stable for many months without any intervention.

Current hardware for KL3RR-2 is a Baofeng UV3R, Mobilinkd TNC2, Raspi3 B running Raspbian and XASTIR.  Antenna is an Arrow J-Pole at approx 30' height.

I appreciate the GUI of XASTIR both for visualization (which is a key outcome of the data produced by APRS) as well as being able to interact and use the station for APRS functions such as messaging.  Coupled with connecting to the raspi via VNC this makes for a functional APRS Igate that is remotely accessible and controllable. 

KL3RR-2 APRS Igate interface via remote connection (VNC).

Sunday, March 17, 2019

-12 Vdc power

Current home setup for powering radio equipment:

Electrical hardware mounted on a cutting board.  Samlex SEC-1230UL 30-A charger, Optima Blue Top 55-Ah battery.  Blue Sea Systems (marine) fuse panel and various other components intended for car audio.
  • The SEC-1230UL is a switch mode supply but quiet enough to not interfere with HF reception.  
  • With the SEC-1230UL and a battery, the system behaves as a dc Uninterruptible Power Supply.
  • With 120 Vac available, the system can maintain a <30 A draw indefinitely (limited by the charger).  However, higher amperages can be sustained intermittently (limited by the battery).

Monday, March 11, 2019


New Mobilinkd TNC 2.2 . Working well so far.  Very quick to setup.  
It links to a tablet, phone, or computer (via Bluetooth) and a radio (via cable).  

The Mobilinkd is a KISS TNC.  It MOdulates/DEModulates between the radio audio in/out and a digital signal sent over the Bluetooth-serial link while facilitating switching of the radio PTT.

The end functionality is completely dependent upon software.  One of the most common uses is for APRS:

Mobilinkd TNC 2.2 w/ Baofeng UV-3R and APRSdroid on a tablet.
The high resolution screen is ideal for mapping APRS data.

The radio and TNC are a compact package.
The Bluetooth is nice as the tablet is not constrained by a physical link to the TNC.