Excellent presentation. I'm curious, you used 18awg copper magnet wire, do you know if 16awg could be used with an FT240-43 transformer? I know it might be a little stiffer to wind but might it otherwise work?
It depends. Thicker wire has lower resistance, what will reduce resistive losses in the windings. On the other hand, thicker wire means smaller distance between windings, what can increase losses caused by inter-winding capacitance. Probably the best way of figuring out is to build two identical transformers, and measure them connected back-to-back. MM0OPX has a great demonstration of loss measurement using this method: th-cam.com/video/TZjY2Jim7fY/w-d-xo.html Of course the winding has to fit on the core, but I don't think it will be a problem in your case.
@@gsudman It is worth noting, that the gains from increasing wire diameter will be limited by skin effect. According to the graph in wikipedia (en.wikipedia.org/wiki/Skin_effect#/media/File:Skin_depth_by_Zureks-en.svg), at 1MHz the current penetration depth for copper is ~0.07mm. This means that the decrease of wire resistance will be proportional to the wire circumference (i.e. wire diameter in the first power), instead of the cross-section area (i.e. diameter squared), what is a case for DC currents. On the other hand, FT240 is such a large core, that the increase in losses caused by capacitive coupling. I think this is a great excuse to do some for some experimentation, and share the results :)
great presentation but also great AV production - loved the consistently good audio and the camera skills. Thanks for all the references, too.
Thanks!
Super presentation! Thanks from a new ham who wants to build one.
You're welcome!
Excellent presentation. I'm curious, you used 18awg copper magnet wire, do you know if 16awg could be used with an FT240-43 transformer? I know it might be a little stiffer to wind but might it otherwise work?
It depends. Thicker wire has lower resistance, what will reduce resistive losses in the windings. On the other hand, thicker wire means smaller distance between windings, what can increase losses caused by inter-winding capacitance.
Probably the best way of figuring out is to build two identical transformers, and measure them connected back-to-back. MM0OPX has a great demonstration of loss measurement using this method: th-cam.com/video/TZjY2Jim7fY/w-d-xo.html
Of course the winding has to fit on the core, but I don't think it will be a problem in your case.
@@ViennaWirelessSociety I appreciate you taking the time to respond. Thanks!
@@gsudman It is worth noting, that the gains from increasing wire diameter will be limited by skin effect. According to the graph in wikipedia (en.wikipedia.org/wiki/Skin_effect#/media/File:Skin_depth_by_Zureks-en.svg), at 1MHz the current penetration depth for copper is ~0.07mm. This means that the decrease of wire resistance will be proportional to the wire circumference (i.e. wire diameter in the first power), instead of the cross-section area (i.e. diameter squared), what is a case for DC currents.
On the other hand, FT240 is such a large core, that the increase in losses caused by capacitive coupling.
I think this is a great excuse to do some for some experimentation, and share the results :)