Re: The small SWL beam (1...30 MHz)
Posted: Fri Jul 15, 2022 8:37 am
LOL !! Well, "Bazinga" would be cool, although maybe probably too "nerdy"13dka wrote: ↑Fri Jul 15, 2022 8:23 amI suggest SLOB then, you know it really helps if the acronym is a word (took me 2 years until I could memorize "NCPL" and 10 for "G5RV/HB9CV/W3DZZ"), or the antenna has a completely unrelated name like "Double Bazooka" for a "coaxial folded dipole antenna".Andrew (grayhat) wrote: ↑Fri Jul 15, 2022 7:08 am Ok, I think we may stick with "SDL" (Small Directional Loop) or "SDRL" (R for Receiving)Hmmm...Bazooka...
![Laughing :lol:](./images/smilies/icon_lol.gif)
Ok, serious now
Let me try a "masterpiece of art"Not sure what you mean by "horizontal run"? In my mind the coax will likely not make that much of a horizontal run, depending on its bending capability) (which is admittedly not so great for the H-155 I'm using), the more snap-on ferrites it gets, the less it will be able bend.Andrew (grayhat) wrote: ↑Fri Jul 15, 2022 7:08 am those shouldn't be a major issue as long as the horizontal run of the coax is choked with snap-on ferrites
![Very Happy :D](./images/smilies/icon_e_biggrin.gif)
the above shows the coax routing, horizontally along the "cross support" arm and then down vertically, judging from currents simulation in NEC, the most effective place for snap-on ferrites should be along the horizontal run of coax
there won't be any "pull" with the config shown above, the coax will just be supported by the same structure supporting the loop; as for the RF preamp, my idea is that placing it at the center of the cross (the point where the horizontal coax turns down) will avoid loading the arm too muchBTW that is the part that causes me the most headaches, having this NooElec Balun sitting horizontally in its junction box at the end of the boom, with the coax putting some pull on the boom and the prospect of chaining another box with the preamp to the balun box. I should have thought of that, there are 90° SMA plumbing pieces available on Amazon. :/
As for currents, here's what the NEC model shows
which shows why I'm thinking that the horizontal segment of coax should be the best suited for the ferrites