Nagoya NA-24 antenna repair

Some weeks ago I bought a new -ultra flexible- Nagoya NA-24 antenna for my Baofeng UV-82L. When I used the Nagoya antenna for the very first time I received almost nothing. I first thought that I (again) bought a counterfeit Nagoya antenna and put this one in the drawer. Just yesterday I found it again and became a bit annoyed as I wasted another 20 bucks here. I decided to open the NA-24 with a pair of two big pliers. The black cover had an internal thread and was fixed with some superglue. With some force I was able to disassemble the whole connector and could inspect all the antenna parts. I found out that the flexible radiator was not soldered on the socket of the antenna so it had no electrical connection to my Baofeng radio. I soldered the radiator to the antenna socket and put everything back together again. I tested the NA-24 antenna on the local repeater while I walked on the streets in the city. It worked flawless.

Tuning the front-end filters

Some days ago I decided to install an APRS RX-only iGate here in my apartment. The iGate simply takes the APRS signals from the air and forward them to the internet. I live almost in the center of the city and I have a free sight over the buildings. Good preconditions for a „fill-in“ iGate I thought. I had a Raspberry Pi and a cheap RTL-SDR dongle (DVB-T stick) for this purpose. Sounded like an easy job first but I received nothing within the next 12 hours. I knew that something must be wrong. In this project I learned more on designing HF-filter than on Linux and Raspbian, what actually was my aim at the beginning of this project. In this blog post I will show you, how I successfully dealt with massive QRM from two 100kw and 2 50kw radio transmitters.

FT-817 interface for digimodes

Some time ago I bought one of these small and light 2 in 1 tablets with Windows 10. The device was very small in size but the battery lasts very long. With only 1,7kg the weight was not too high for my portable ops. I did not take it into the field yet. The reason was simple: The tablet has one USB-port only. I need one port for the USB cat lead and another one for the USB-soundcard to connect my existing PC-interface made by Alan, M0AQC. After a long search on the internet I did not find a simple FT-817 interface with one USB lead, CAT-control and built-in soundcard. So what did I do? I built an interface that meets my requirements by myself.

Built FT-817 android interface

Some time ago I came across the Wolphilink Interface. It's a small box which connects an smartphone to a Yaesu FT-817/857/897 transceiver. I was about to buy one, but the interface was quite expensive, especially if you include the optional cables and the shipping to my QTH in Germany. I googled a bit and found an interface built by Christian Petersen, DD7LP. I made the decision to take a closer look on his schematic diagram and built my own interface to use APRSdroid and PSKdroid on my FT-817. Luckily Christian also provided a buying list besides the schematic diagram. As I don't have any knowledge and also no tools to etch a circuit board, I first planned to build the circuit on a simple stripboard.

Built 3S1P 18650 pack

In this article I will describe how I built a cheap DIY 18650 Lithium-Ion battery pack for my Yaesu FT-817. After 65 SOTA-activations and other outdoor operations like IOTA, WWFF I had to reduce some addional weight of my „go-bag“. I already went from RG-58 coax to RG-174 and also scaled-down the diameter of the antenna wire, but this is a different story. So I looked what is on the regular market and found a lot of people in the amateur radio scene who are using Li-Po (lithium polymer) packs. Those packs are usually made for RC purposes and in the first moment I thought that they perfectly matches all of my needs. They are cheap ($15 per 2500mAh pack) and a 3S pack (3 cells in series) gives 11.1V nominal output.

EFHW tuner almost build

I used the sunday last week to built the SOTAbeams Mountain Tuner kit for 40-17m. After I built my own tiny EFHW-tuner, I ordered the SOTAbeams kit in the UK, which arrived 7 days after my order here in Germany. I needed a little bit more than 60 minutes for everything including testing. I used the instructions some weeks ago to built the same tuner out of stuff I had in the junkbox. I wanted to compare my work with the commercial tuner and also I liked the design with the plate. You see my construction on one of the photos. The SOTAbeams one was much easier to built, it has a very smart design. For some 18 bucks this tuner is a must have. I went to my local GMA summit (DA/SR-059) to test the tuner with my ultralight linked endfed, which I posted some days ago here in the group.