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.

EFHW-antenna from ultralight wire

I go lighter and lighter and lighter... I've built a new EFHW wire for my SOTA-activations last weekend. The antenna is "linked" and is full halfwave on 40/30/20/17m. I went from 0,75mm² (~18 AWG) to 0,14mm² (~26 AWG). Thank you Andreas, DB2AJ for the hint. That saves some additional weight. I use this thin wire together with my homebrew EFHW-QRP tuner. I use a pair of 2,6mm "Zwerg-Stecker" and "Zwerg-Kupplung", with the plastic housing removed, for every link. For optical reasons and also for more mechanical stability, I added som heat-shrinking tube to the connectors. The wire-winder came from SOTAbeams UK and they fit perfect to this easy construction. The whole job did not take longer than about 60 minutes.

MX-P50M y-cable

Okay, well this is my first article in English here. I decided to do this, because I get lots of question from outside of Germany about my experiences with this small chinese linear amplifier. Thanks to Peter, HB9FGQ who answered on my topic on the FT-817 Facebook group, I was able to make myself a y-cable for my chinese MX-P50M amp. Now I can hit PTT for digital modes such as PSK or JT-65/9. Also the QRG-reading on the electronic logbook is now working fine, as this construction lets the CAT passes through. I went to my local electronic store (Conrad Electronic) which had the needed parts on stock. After I picked up the items I needed about 3 hours for everything.

Ultralight dipole

In letzter Zeit hat mich mein alter Dipol immer mehr gestört. Er hat mich bei über 30 Bergaktivierungen begleitet und immer gut funktioniert. Sein entscheidener Konstruktionsmangel war zum einen, dass ich 1,5mm² (teiweise 0,75mm²) verwendet habe und die mittige Einspeisung über eine längliche Abzweigdose erfolgt, in welche ich eine PL-Buchse eingelötet habe. Als Zuleitung verwendete ich ca. 7m RG-58 mit PL-Steckern. Dieses An - und Abschrauben kostet auch unnötig Zeit. Ich wollte also Zeit sparen und leichter Wandern. Ich habe einfach 0,5mm² bei der neuen Version genommen, welches ich sowieso noch hatte und habe es fest an ein 7m Stück RG-174 mit BNC-Anschluss gelötet. So spare ich die Abzweigdose und habe sogar Steckerverluste minimiert. Als "Träger" für meine Konstruktion verwende ich ein Stück Gehäuseblende des Laufwerkschachtes meines alten PC.