26" bicycle rim magloop

I was out for a walk in my city when I found this old 26" bicycle rim in the brushwood close to the rail tracks. I removed all the crusty stuff and added a  variable capacitor with around 15-120 pF. Some time later I was able to work RA3BL in Moscow 2.200 km way on 30m. The efficiency on 10 MHz is only 5% on such a small loop but it worked. I later worked LA9NKA on 12m, K8JDC on 17m, DK3KUD on 60m and highlight was VP8LP in Falkland Islands on 17m who was 12.700 km (7.900 mi) away. Unbelievable. I like this antenna a lot and can highly recommend it. I try to source some old 24" and 28" rims to compare them. 28" should be the best option there performance-wise but you need a capacitor with a low starting capacity, otherwise you probably lose 10m.

Yaesu FT-65 FT-25 FT-4XE FT-4VR

Some time ago I received a Yaesu FT-4XE. Programming, especially if you have to set a CTCSS, is a pain. I can tell you this is no joy. In the time that you spent in programming one chanel you can easily convert an old baofeng programming cable into one for the Yaesu FT-65, FT-25, FT-4XE or FT-4VR. I found a nice video on Youtube and needed only one minute to complete the project. With this easy modification I was able to programm all my local repeaters into the radio. As of today (Feb 2019) chirp does not support those new Yaesu handhelds yet. But luckily Yaesu has a free programming tool on their website. You can modify all parameter such as QRG, CTCSS, DCS, Power Level, etc. I had no spare 2,5mm plug so I just removed the 3,5mm plug from the Baofeng original one. GND was already correct, TX and RX had to be changed over and one diode (0,6V drop on my one) had to be soldered in. Life can be simple - sometimes.

Motorola MC Micro Umbau

Am 21.Oktober 2017 habe ich auf der Rheintal Electronica einige Motorola MC Micro gekauft. Gegen Ende der Messe bekam ich den ganzen Posten so günstig von einem netten OM, so dass ich die Geräte einfach kaufen musste. Nachdem ich bereits einige Ascom SE540, Nokia RD40 und Motorola GM1200 bzw. MC2100 so modifiziert hatte, dass ich die Geräte im Amateurfunk nutzen kann, bot sich das auch mit den MC Micros an. Eines der neuen Geräte war ein MAU14EZA9J13AK und bereits mit 8 Kanälen auf Amateurfunk programmiert. Man braucht ein reines DOS-System mit einem 386er, um das Gerät zu programmieren. Mit DOS Box läuft die MC Micro Software nicht. Bisher konnte ich die Frequenzen daher nicht anpassen. Bei den anderen Geräten handelt es sich um MAU14EVA5G22BU. Diese sog. EVA5-Geräte können mit einer alternativen Firmware von DG1YFE auf ein echtes Amateurfunkgerät umgebaut werden. Man kann nicht nur die Frequenz direkt auf der Tastatur eingeben, man kann auch Repeater-Shift frei einstellen.

Pixie on the Spectrum Analzyer

Two weeks ago I ordered the S-Pixie kit for 4,79 Euro on Ebay incl. shipping and case from Hong-Kong. It took exactly 2 weeks to arrive. The kit came in a plastic bag as usual and included no instruction and no manual. I also got 7 more resistors and 5 more capacitors than needed. I found the schematics and part list online, so the assembling (with double-checking everything) took me about 2 hours. It worked on the first attempt and I received morse code on around 7023 kHz. While hooked up to my bench power suppy I checked the output power vs. the input voltage. 300mW output are reached with 11V only. For me that sounds like a good sweetspot and as the transistor Q02 will get very hot on TX, this is a good value for the battery voltage. I later googled and found out that the Pixie is oscillating also while it is in receive-mode so I hooked it up to the spectrum analyzer to see if this is true and to also check the transmit spectral purity. My Pixie is pushing 6mW on 20m, while sending morse code on 40m. Not a good value.

DIY Kits 70W SSB linear

Some weeks ago I bought a chinese amplifier kit on Ebay which came for 16 Euro / Dollar shipped. The kit took only 2,5 weeks to arrive and came in a simple plastic bag without any protection and it also came without a manual or instructions. But even if it does not work, the parts alone are worth the money. While waiting for the kit I found an interesing article from John, PD7MAA on his website. He does not only have the schematic available, he also shows how nice such DIY-projects can look like. Especially the filter is worth a look. Building the kit was not too hard, but the surface-mount (SMD) parts are very tiny and you need a calm hand and good eyes. When I had everything assembled I tested it without a heatsink on the two IRF530N mosfets from IOR. It took not more than five seconds to kill both FETs while sending an AM carrier (1,5W drive). I ordered a pack of five new IOR IRF530N mosfets on Ebay which arrived today. After the QRL I soldered them in, and I drilled the holes into two pieces of an old heatsink harvested from an old PC power supply.

Motorola RIB DIY style

After I had some massive problems with a chinese Motorola RIBless knock-off, I decided to make my own 100% Motorola spec matching RIB with the 'original' parts. The original box is somewhat around 200 Euro here, far to much for an radio-amateur and to program a single old 1995s Motorola GM1200 only. On batlabs I found a good source for schematics and part lists of the original RIB so I took an old board and some spare parts from the junkbox and made my own RIB. I only had to buy 3 parts (LM311 - Voltage comparator, ICL7660 - Voltage Converter and a few 1N4148 diodes), so the whole project was around 5 bucks in material, time for sure not calculated.