I happened to stumble across some antenna projects showing common mode chokes 1:1 baluns made of some turns of coax wound on T200-2 iron powder toroids. Will they work? The role of a choke A choke BALUN works by letting through the differential current and by hindering the common mode one by opposing some impedance. The key […]

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In my experience with computer antenna simulators (I mostly use 4NEC2), I had the feeling that those tools, if correctly employed, can be quite accurate. Unfortunately, when working on shortwave antennas, the interactions with the surrounding environment make the results a bit approximate: such long wavelengths make impossible, at least for us hobbyists, to avoid the environment to […]

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that is the question, for many ham radio operators. A simple, resonant, single band, plain-vanilla horizontal dipole, does really need a 1:1 balun… or not? To investigate the differences between a dipole having a 1:1 balun and another one directly connected to the coaxial cable, I build a 40m band dipole with a remotely controlled switch […]

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It can happen that a “PC Programming Password”, set on the Tytera MD-380/Retevis RT-3 “CPS” programming software, is lost or forgotten. If that happens, there is no way to program the radio from your PC ever again. However, there is a simple workaround: install the md380tools by Travis Goodspeed KK4VCZ; follow carefully his instructions for […]

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The recent Tytera MD-380, also known as Retevis RT-3, is very nice DMR portable UHF rig. However, one of its weak points is the programming software. While DMR for utility use often requires simple programming, when used for HAM radio, the big and evolving number of available repeaters, users and zones makes programming a big […]

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One of the most tempting all-band cheap antenna solution when a lot of space is available is the “long wire”. The idea is to lay a wire as long as possible and to feed it at one of its ends, while the other pole is grounded. Some kind of fixed impedance transformer plus maybe a tuner […]

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In the world of HAM radio, there are several myths that survive through generations despite them clashing with laws of physics. However it is quite interesting to see how easy is to debunk some of them with very simple experiments. The radiating line myth In HAM radio discussions “experts” frequently advise against antennae tuned by a tuner […]

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[PL-259 vs. N on 430 MHz follow-up] – Many OM assert that they can not withstand the performance penalty introduced in the 430 MHz band by a SO-239/PL-259 pair. Curiously, all the major rig makers seem to ignore this fact. For example the Icom IC2820, the IC7000 and the newer IC7100, the Yaesu FT857/FT897, Alinco DR635, Yaesu FTM-400 and the new Yaesu FT991, among […]

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[Read also the follow-up: PL-259 vs. N, round 2: hard testing] Ham radio makers often offer two distinct connectors for the 2m/70cm port: N for the European market, SO-239 for USA/Japan and the rest of the markets. This is taken from the Yaesu FT857 manual: Here in Europe I often read on ham radio forums that […]

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Introduction One of my favourite hobbies is to trek and climb the Alps and do ham activity wherever I reach. During the warmer seasons, I often reach high summits: what better place for some VHF activity? So far I worked with a 4-elements 1m long Yagi-Uda that I designed and built myself with plastic and […]

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