Omega-TI wrote: ↑Sun Jan 28, 2024 2:44 pm
I'm going to build this one in the spring when the weather gets better due to the HOA's in my retirement complex. I mainly plan to use this from the 5-30 shortwave bands. So how long is too long for the wire length? I figure most of my listening will be in the 31 meter band.
There's no "too long", the longer, the better performances you'll get on the lower frequencies, other than that the antenna impedance curve is almost "flat" due to the loading resistor, if you make it using insulated wire and choose some "neutral" color it will be almost invisible, at the top use a small box/enclosure hosting a "chock block" connector to host the resistor and at bottom another small box/enclosure to host the balun, willing to further hide the antenna, you may consider applying some artificial (plastic) climbing plant to the wire, in such a case, ensure those don't have any metal inside and consider that with rain/mist they may cause some issues to the antenna reception
As for the antenna pattern, it depends from the overall antenna perimeter (length), in general at low frequencies (say up to around 7MHz) it will be almost omnidirectional, going up in frequency it will have two main lobes perpendicular to the loop plane (that is toward front/back), going further up to V/UHF the lobes will be parallel to the loop (toward left/right), the gain will depend from the loop perimeter too, in general it will raise going up in frequency, but the performance should be more than acceptable w/o the need to use a preamp, the preamp may be only useful at the lowest frequencies
HTH and by the way, if/when you'll go on and build it, please come back and report how it worked for you

!
[edit]
even if you'll be going to put the antenna together next spring, you may start collecting the needed bits and pieces, in particular the "NooElec BalUn 9:1 v2"
https://www.nooelec.com/store/balun-one ... bones.html which is a nice one, stay away from chinese 9:1 since they're far than good; as for the resistor, ideally you'll want a non-inductive one, but a regular 1/4W, 1K5 resistor will be an acceptable compromise, as for the insulated wire, small enclosures, nylon cable ties and so on... those may be easily sourced locally at most home improvement stores