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Why Your EchoLink Node Fails on 4G/LTE & Starlink: A Deep Dive into ISP Traffic Shaping, CGNAT, and the TCP Proxy Solution

Hello everyone, I am back with a new post after quite a long break. As many of you know, the EchoLink system I set up in 2024 for the Kapaklı Branch of the Turkish Radio Amateurs Association (TRAC) - YM1KPL - was working flawlessly on a fiber internet infrastructure. During that initial setup process, I had struggled quite a bit with the plague of CGNAT, which forced me to obtain a static IP and deal with complex port forwarding configurations. We had successfully completed the testing phases, but later, due to a change in location, we were forced to run…

  • Reading time:21 mins read

APRS0ISS: Automatic Frequency Switching Project for ISS Passes with Pi Zero 2 W and RTL-SDR

Shortly before starting amateur radio, I became interested in Software Defined Radio (SDR) due to various expectations like being able to visualize signals in the air, essentially "seeing" the FM radio broadcasts I'd listened to for years while tuning in. Before long, I bought a Chinese RTL-SDR radio with a USB interface and started using it. After diving into amateur radio activities, my enthusiasm for radio listening with the SDR faded, and the device was eventually tossed into a drawer. It was destined for its eternal resting place—the infamous "box full of cables stored for a lifetime"—until I discovered APRS.…

  • Reading time:4 mins read

ABeS Aprs Beacon Sender Project

ABeS APRS Beacon Sender is a Python-based software project designed to automatically send the location of radio repeaters—or even individual operators—to APRS servers over the internet. The idea came to life while I was running an EchoLink system for the Turkish Amateur Radio Association Kapaklı Branch. Since the system was online 24/7 and functioned solely as an EchoLink server, I wanted to add an extra feature to make it more useful. My goal was to share the repeater’s location and frequency information via APRS, allowing amateur radio operators outside its coverage area to view this data on aprs.fi. About seven…

  • Reading time:3 mins read

Sending APRS to the International Space Station (ISS)

When I first saw Murat Şen's YouTube video titled “Make Your Voice Heard by the International Space Station” back in 2018 or 2019, I remember asking myself, “Could I do this too?” Even though the idea popped into my mind from time to time over the next 6–7 years, I couldn’t fully focus on it due to the pandemic and work-related responsibilities. But when I finally achieved my first goal of becoming a licensed amateur radio operator in the second half of 2023, I had just one question on my mind: How can I make my voice heard by the…

  • Reading time:7 mins read