Category: Ham Radio
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svxTalkie
I’ve been toying with the idea of building a walkie talkie based on the svxLink software and Raspberry Pi Zero W platform. I found a really nice audio board that has two microphones, a headphone jack and speaker output that implements the I²S (Inter-IC Sound) digital audio interface standard. FWIW, it’s pronounced “eye squared S”.…
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SVXLink Interfaces
I’ve been running the svxLink application written by Tobias, SM0SVX for some time now. I installed it on our local VHF repeater back in 2018 using a Raspberry Pi 3B+, and an audio/PTT isolation board. I’ve been looking for new, improved or simplified interfaces to interconnect svxLink with repeater controllers and simplex node radios. Some…
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Ham Clock
Some time ago, I bought all of the parts to build a HamClock. Ed, WA6ED mentioned this project on the 40 meter net a while back. I finally got around to building mine in September, 2020. HamClock runs on Linux (Raspberry Pi, single board computers), or Arduino platforms. The Arduino version was written for an…
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TM-731A Battery Replacement & Backlight LED Modification
I recently repaired a Kenwood TM-731A 2m/70cm mobile radio. It appeared that the backup battery was dead since it would no longer retain any memories after power was removed. Checking the battery, it was indeed dead. I replaced that but noticed the board was coated with what could have been electrolyte leaking from the dead…
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Remote control for the Repeater Site
Howard, KG6GI and I installed the first D-STAR repeater system for the SOARA club in early 2007. During the process, we realized that we needed a way to remotely disable this new repeater system should anything go wrong, and to meet our FCC obligations. Howard had already obtained a network connected relay and opto-isolated input…
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Repairing Maggiore R1 Repeater
The SOARA 224.100 Repeater became intermittent and stopped transmitting a few months ago. I finally made an appointment with the Laguna Beach water district to visit the site on May 28th. Once on site, I quickly determined that the repeater had no power output. Keying the repeater did engage the transmitter, but nothing was heard…
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TM-742AD no TX audio
I noticed an old TM-742AD in a friends garage recently. It had been disassembled and had a label on it that read “Defective Unit” – that piqued my interest! I brought the radio home and put it on the bench. The radio powered up but all of the memories were reset to default frequencies so…
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FT-911 low-audio repair
My Brother recently took his old FT-911 23cm handie talkie out of storage and powered it up. The radio worked, but the output audio was very low. Tracing the audio path, I found sufficient audio at the output of the LM386 audio amplifier and the only component between the speaker and that was an electrolytic…
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Alpha Delta Coax Switches
I have one primary HF antenna, a Hustler 6BTV (6 band trap vertical). I was using an Alpha Delta 4-port coax switch to switch the antenna between my K3, K2, and coax that I use on the workbench. This morning when I listened for the SOARA 40 meter net, signals were very weak. SWR was…
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Arduino KISS TNC
Mobilinkd (http://www.mobilinkd.com) is the producer of very compact and capable bluetooth enabled KISS mode TNCs that are used with APRS applications on Android, iOS, Windows, and Linux, and Mac OS. Their original prototype was built using the Arduino platform. On their website, they provide breadboard descriptions of various TNC designs including an Arduino based KISS…