NJ6N’s Amateur Radio & Electronics Blog
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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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Tivo Power Supply Repair
I’ve got a very old Tivo, an HRI-250. Last week we had a major power outage that lasted 12 hours. When the power came back on, my Tivo did not. It had been having some over-heating problems, so I wasn’t surprised. Investigating further, I found that I was missing some of the supply voltages. The…
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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…
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PowerPole Power Panel
SOARA has “battery box” building events every so often. The idea is that you build a portable container with a battery, cigar lighter socket, power switch, volt meters, and Anderson PowerPole connectors that you can use during an emergency. I have designed and/or printed and built several such breakout boxes. I built a Pelican case…
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YAdmHS – Yet another digital mode hot spot …
I got to thinking about how I could make a thinner MMDVM based multi-mode hotspot with a Nextion display. I decided to try mounting the boards next to each other instead of plugging the MMDVM board into the Pi ZeroW board. I also wanted the case to have rounded corners. Here is what I came…
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Tip Organizer Tip
I’ve got way too many different Weller soldering Iron tips for my temperature controlled Weller ET and PT soldering irons. It finally occurred to me that I should create a tip organizer for them. I drew one in Sketchup and printed on my Hictop 3D printer.
Got any book recommendations?