Somehuman on Hefty 3D Printed Quadcopter Meets Nasty End.Retro Gadgets: The 1974 Breadboard Project 31 Comments QST had some good articles about that a couple years back. Besides, once they get the feel for RF via building QRP they can always turn around and build a QRO amp. Keep encouraging more hackers to homebrew and maybe finding someone who can receive at the various QRP watering holes will be easier. When no one is answering they can always verify that their project works with test equipment, a receiver, online SDRs or the reverse beacon network. It’s better I think to encourage builders to build but just let them know that QRP contacts are more like fishing than phone calls. model number this, model number that, nary a technical detail, bad politics or old-age maladies. How excited is such a person going to get when instead of building a rig they buy a black box then they find out all the conversations are either people talking about their store-bought rigs. I’m not sure that encouraging someone whose main interest in in building stuff that they should start out by going QRO is a great idea either. Giving a beginner false expectations that they will make a contact every time though. Using QRP is good for the finals, after all, hi. IMHO, it’s better to call CQ with normal power and then, after the QSO is established, go down to QRP levels. Experimentation, homebrewing and curiosity are the roots of amateur radio.īut always advertising QRP to beginners can backfire, as they may quit the hobby due to sheer frustration. These modes work below the grass level, so to say.ĭon’t get me wrong. Unless you’re using PSK31, FT4/8 or WSPR. In the city, with space limitations, QRM and electro-sensitive neighbours, it’s really hardĪnd frustrating to get into a real QSO with low-power. Unless you’re operating on an open field with good (proper) antennas or have an efficiency fetish (a passion for testing most efficient transceivers, PSUs, cables and antennas). Say two 20m wires on a 10m high pole for 80m operation. Or if you’re running a 10W QRP transceiver on a half-wave dipole. Indeed, if QRP is defined as 25-100W instead of 10W then it’s all reasonable. Posted in Radio Hacks Tagged atu, ham radio, radio Post navigation As usual, protests that he not an expert and that he’s just documenting what he did, but he always does such a good job of presenting the calculations involved in component selection that any ham should be able to replicate his builds. A final video shows the tuner in use in the field, with a NanoVNA proving what it can do. The second video below shows the final implementation of the tuner as a fan of QRP, or low-power operation, favors simple, lightweight homebrew gear that can be easily taken into the field, and this certainly fits the bill. A small meter and a diode detector indicate when the bridge is balanced, which means the transceiver is seeing the proper load. A toroidal transformer with multiple taps and a variable capacitor forms an LC circuit that matches the high impedance antenna, in this case a multi-band end-fed halfwave, with the nominal 50-ohm load expected by the transceiver. As he explains in the first video below, his tuner design is really just a Wheatstone bridge where the antenna forms half of one leg. recently did this with a simple antenna tuner, a device used to match impedances between a transmitter and an antenna. That doesn’t mean antenna topics have to remain a total mystery, of course, especially once someone takes the time to explain things properly. On the face of it, hanging out a chunk of wire doesn’t seem like it should be complicated, but when you dive into the details, building effective antennas and matching them to the job at hand can be pretty complex. If there’s anything about amateur radio that has more witchcraft in it than the design and implementation of antennas, we don’t know what it would be.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |