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.

RIBless GP300 programming

Some of you guys might already know - I love Motorola gear. Some time ago I received a 1995 Motorola GP300 from a friend. This old radio was used for the local fire department just before they switched over to digital. I had this one lying around as it was programmed in the 170 MHz range ("2m BOS" here in Germany). I thought I could safe some time for making my own RIB, so I ordered a RIBless box on Ebay which came straight from China for 13 Euro shipped. Not a bad deal. In the end I wasted all the day in troubleshooting and found that some real amateurs are assembling those electronic devices over there in China and also it seems as there is absolutely ZERO quality control. If you are not too good on electronics and troubleshooting electrical devices, better get yourself an original Motorola RIB, there you can be 100% sure that it works (or of course make your own one).

Nokia RD40 nach dem Umbau

Vor ein paar Wochen brachte Norbert, DL8GZ ein Nokia RD40 zum OV-Abend mit. Er hatte keine Verwendung mehr dafür und nachdem es wohl mehrere Jahre im Keller lag, konnte ich es zum Umbau haben. Wie sich später heraus stellte, handelt es sich um ein 70cm Bündelfunkgerät, welches vom Aufbau her unheimlich robust und hochwertig wirkt. Im Internet fand ich die kompletten Service-Unterlagen und Schaltpläne zu dem Funkgerät. Ein Niederländer hat auch eine Umbauanleitung im Internet, diese zu verstehen war jedoch trotz Google-Übersetzer nicht ganz einfach. Nach ca. 10 Stunden funktioniert das Gerät nun auf 70cm im Amateurfunk-Bereich. Nachdem ich die Anleitung gelesen hatte, fand ich heraus, dass ich ein serielles SMD EEPROM vom Typ 24c02 und ein 100kOhm Widerstand in das Bedienteil einlöten musste, um softwareseitig überhaupt die Berechtigung zu erhalten, Parameter wie Frequenzen im Gerät zu ändern.

Magloop selber bauen

Ich wollte schon länger eine Magloop selber bauen, da ich von der Idee fasziniert war, mit einer kleinen Antenne aus meiner Wohnung heraus QRV zu sein. Außerdem waren mir die kommerziellen Lösungen einfach zu teuer. Für eine günstige Antenne ist man schnell 400-500 Euro los. Mechanisch etwas stabilere für den Dauereinsatz draußen kosten schnell über 1.000 Euro. Nachdem ich ein wenig gegoogelt hatte und einige Funkerkollegen zu dem Thema interviewt hatte, habe ich mich dafür entschieden einfach eine "Quick & Dirty" Magloop hinzuzimmern, um dann am Netzwerkanalysator zu schauen was passiert. Dazu bin ich am Wochenende mit Peter, DC2ZO in den Baumarkt und wir haben uns für je 12 Euro die Bauteile gekauft, um die Antenne schon mal hinzustellen.