NJ6N’s Amateur Radio & Electronics Blog
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10 Meter Vertical Dipole
I recently built some coaxial vertical dipoles for the 6 meter band to use with my converted Maxtrac radio on FM. I designed a 50mm coil form with holes in the ends to capture the coax. 2 inch (~50mm) diameter PVC pipe would work also. I learned about this easy to build coaxial dipole from…
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Batteries America EMS-20-28 Charger Repair
I recently came across an aftermarket rapid battery charger for an old Alinco DJ-280 220 MHz Handie-Talkie. When I plugged it in, there were no signs of life. So, I looked inside and found a very crispy 1/2 watt resistor in circuit with an NPN transistor. I had to guess at the value of the…
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Fun with (IoT?) Displays
At one of the repeater sites there is a remotely addressable power control system. Right now we’re running on emergency generators after a fire took out the power distribution system to the mountain. I thought it might be useful to have a remote display that would reflect the site status. Towards that end, I wired…
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Convenient Workbench Power
The super convenient under-shelf Anderson Powerpole distribution panel that I made some time ago started to show signs of wearing out. The connectors had become loose inside the PLA. So, I designed a new version that’s similar to a standalone tabletop Powerpole distribution strip that I built recently. Instead of having flush mounted Powerpole connectors,…
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LED S-Meter for /\/\otorola
I have been using Motorola CDM-750/1250/1550 radios to build digital and analog repeaters, full duplex links, and digital hotspots for some time. Quite a few of the radios I have do not have a front panel display. However, they do have a 16 pin accessory jack that has all of the usual signals including TX/RX…
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Dire Wolf & YAAC for APRS
I had an old Icom ID-880H lying around. The ID-880H has something many radios lack, a Data port! That gave me an excuse to buy another Masters Communications Radio Adapter kit! The DRA-50 is very similar to the RA-35/RA-42 interfaces that I’ve used before. The DRA series of adapters are designed to be used in…
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K3NG Electronic Keyer
Recently, someone mentioned they were looking for a code practice keyer during one of our HF nets. I have a few older keyers in my collection including a CMOS keyer that I built from a QST article back in the early 80’s or so and a Logikey K-1. I had recently built a very simplistic…
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Quansheng UV-K5
I have been a fan of the firmware modified Quansheng UV-K5 handhelds for a while now. The base radio is not bad and the features added by Hams through firmware modifications have been very useful. The radio is available through the usual sources including AliExpress, Amazon, Ebay, etc. The radio is known as the Quansheng…
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Malahit/N7DDC ATU-100 EXT Antenna Tuner
This is a 100 watt HF/6m Antenna Tuner kit sold through the usual consumer sites like Amazon, Ebay, and AliExpress. It was apparently designed by N7DDC. I happened to run across this tuner kit while looking for something else on Amazon. At $30 or so, it was cheap enough to take a chance on and…
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Automatic Power Off
I have used an APO-3 automatic power off unit in my vehicles for many years. I recently needed to add a second one for my rear-facing dash camera in my truck and wondered what it would take to design and build one myself. I decided to use an Arduino Nano as the microcontroller since I…
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