Amateur Radio

Thanks for the suggestion, the ladder-line J or slim jim seems fairly straightforward to construct with good performance.

From what I've been reading in QST, this sun spot cycle is opening up lots of dx on 10m

I currently have an end fed half wave for 10 meter. I've been able to receive fairly well, picking up beacons from Australia (I'm in Washington state), but haven't been able to make contacts. I just ordered a nanoVNA so I can check the swr with the feed line.

For the feed line, I'm planning to make a feedthrough window insert using some thin plywood and barrel connectors. I'll put some mason line on the plywood so I can lower it to the ground during storms, raise it up to the window and connect when I'm operating.

antenna making is art of tradeoffs. there are different ones between size, cost, weight, mechanical and electrical complexity, wideband performance, radiation pattern, efficiency, and use of harmonics if any.

for VHF and up, it only makes sense to make single band antennas because cost and size savings are tiny otherwise, but bandwidths are large and there are no reasonable autotuners. there are special cases such as 2m/70cm antennas that can do both, but that's it. this is area of simple or folded dipoles, halos, yagis, LPDAs, helical antennas, and in bigger end of scale antenna arrays and optical-like systems like parabolic reflectors

for HF, if you have budget and real estate for it, some of best antennas money can buy would be LPDA for entire range you're interested in. this thing, however, for 3-30MHz range would be a giant aluminum triangle 40m wide, 50m long, weights well over a ton and needs mast and rotator because it's directional, not to mention that it costs fortune. but on balance it can reject noise from wrong directions and is always matched

some typical approaches are as follows:

1. single band wire antennas. these would be halfwave dipoles in any shape (straight, inverted-v, slopers, off-center and so on), j-poles, groundplane antennas, quarterwave dipoles (requires good ground) and couple other variations. these are light, cheap, efficient, fit entire single band without gross abuse of finals, have uniform radiation pattern. but only on one band, and having multiple of them in proximity can lead to weird effects, so these are best if you're hiking for example, but good in general

2. principally single band wire antennas but now we also want to squeeze some other bands out of it. these are dipoles - normal or OCFDs, full wave loops in one approach and trapped dipoles in other. in first case, we exploit the fact that there are usable harmonics on some bands - 80m has 40m, 30m, 20m, 17m, 15m, 12m and 10m. 40m has 20m, 15m and 10m. 20m has 10m. but depending on type not all are always usable and higher harmonics will have narrowed usable band compared to single band case. in trapped dipole approach there's a limit on how many traps you can put (mitigated to some degree if you make it asymmetric and put traps on one side only), and as traps work as coils, these shorten antenna which also narrows usable bandwidth but now for lower bands, opposite of the former. use of autotuner and low loss transmission line can make it work over wider bandwidth, but this only goes so far. note that some bands are narrower than others (12m, 17m, 30m, 60m) and it can be made to work for these pretty well, but less so for others (80m, 40m, 20m, 15m, 10m), but it can still work if there's less bands on one antenna, especially if you're not interested in entire band (like for CW-only or voice-only operators), are willing to accept some loss of power, or use tuner, or combination of some of these

3. antennas that are by themselves not resonant at all. these are either lossy (like terminated dipole) or require tuner, sometimes purpose-built and can be narrowband when tuned (doublets, magloops) both can be reasonably compact. because match lies in tuner, these are multiband by virtue of changing tuner settings. terminated antennas have good match but also you can be dumping half of power or more in resistor. there are also ways to use mast antennas in this way, even if they are grounded (using gamma-match for example)

4. antennas that have to be extensively electrically shortened because wavelength is huge. these are generally everything from 160m down. these are things like magloops and bespoke wire antennas with loading coils and capacitive hats and such. because these are short in comparison to wavelength, efficiency is small and bandwidth is tiny (but can fill entire band) but also require extensive space just due to how huge wavelength is

5. some directivity can be achieved by making yagis (higher part of HF) or by deploying multiple antennas in an array. depending on band and type of antennas this can get very elaborate and expensive. simplest and cheapest way uses multiple radiating halfwave elements connected by coils, or with parallel parasitic elements. this can get decently directional while also being a bit compact but also this makes it more narrowband and due to large size only makes sense for higher HF and VHF

but start simple. single band wire dipole or j-pole would be probably best in your situation