You'll probably get as many different suggestions for SWL antennas as you do CB antennas
I can only give you my personal experience of SWL man and boy.
In the "old" days it was just a case of slinging up the longest bit of wire as high as you can and that would do the job. This still holds true but I have noticed the noise floor increasing, (modern electronic equipment RFI), as well as mains borne noise.
To get round this somewhat I made a fan dipole array with each dipole tuned to my main bands of interest, (80m, 40m, 20m & 10m), and thought I'd built the ultimate antenna. It worked well and after 20 years it's still up. It's only recently that I've played around with alternatives...
I experimented with a homebrew magnetic loop and although it adds another tuning control it's amazing how well it works for such a small antenna. You can also rotate the loop and null out local interference but it was definitely down on signal compared to the fan array.
I recently had someone put up an inverted v dipole for CB transmission and added an antenna switch so I could easily changeover for SWL.... but realised only a few days ago that I'd been short wave listening on the 11m inverted dipole! Going back to an 80m transmission I could tell no difference in signal between the array and the v proving the point that a "long" bit of wire high up is still holds true
The mains borne noise floor seems to follow a comb filter pattern, quieter on MW commercial and amateur bands but very noisy in-between, (including the CB frequencies!) I think this is due to the power companies doing their best to reduce noise for those that complainants loudest
Not that it matters too much nowadays as the commercial SW stations of old have all but disappeared.
So as boring as that sounds, pretty much just a long bit of wire will do the job
There'll probably be suggestions for ATU's, (may help pre-select but your radio will handle that well as is).
Be careful of earthing rod suggestions!
Maybe suggestions of QRM eliminators and unless you build one yourself they're blooming expensive. Surprisingly they do little except null local interference which will usually be more local than you think! (Chinese phone chargers, LCD monitors etc. unplug them or move them further from the receiver.)
Don't think I can add more, (bored you enough already...ha, ha!)
Whatever you do, enjoy. I've been an SWL for as long as I was first old enough to reach that tuning dial and still enjoy it today
All the best,
Theory means that we know everything, but nothing works.
Practice means that everything works, but we don't know why.
Often, however, theory is closely related to practice.
It means nothing works and nobody knows why ...