Hi Rob, Front to back ratio all depends on the arrival angle of the signal, and the portable flag directional properties are just like full size flag directional properties assuming you select the appropriate termination resistor. On my portable flag website I show front to back ratio vs elevation angle when using a 680 ohm termination resistor versus using a 820 ohm termination resistor and you will see that you can move where the front to back ratio peaks to a higher elevation angle if using a 820 ohm termination resistor compared with using a 680 ohm termination resistor. I use a 680 ohm termination resistor because I wanted best performance for ground wave based signals but if I wanted to reject skywave signals off the back of the antenna versus local noise I would use a 820 ohm resistor as an example. Here is a link to my website where you will see the plots I mention: https://sites.google.com/site/portableflagantenna/
73, Don (wd8dsb) On Wed, Feb 24, 2021 at 6:31 AM Rob Atkinson <[email protected]> wrote: > Bi-directional loops lose their directivity for the most part, when > being applied to skywave signals. Is this mini-flag still > unidirectional on skywave? I would think not, but must ask. > > 73 > Rob > K5UJ > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
