You need a cheap price homemade antenna to listen a band on SW ?
The inverted V antenna is nice if you have a garden. You can use a mast or a tree to put the top of the antenna.
Just buy coaxial cable, PL259, electrician wire, domino and nylon rope. Can can make your isolators.
With a SWL inverted V dipole antenna for 10 meter band you can also listen 20 meter band.
If you want to make a SWL half-wave antenna for 20 meter amateur radio band the length of your antenna will be 10 meters ( 2 times 5 meters )
I find an interesting article about this aerial.
You can use to listen or if you are CB radio operator to make contacts. Also many amateur radio operators use this inverted V antenna.
Imagine you like to listen 10 meter band, you can build a half-wave inverted V dipole antenna of 5 meters long only. Each side will be 2.50 meters
Inverted V Antenna – A popular Dipole variant
Please read this complete article write by Basu VU2NSB
https://vu2nsb.com/antenna/wire-antennas/inverted-v-antenna-dipole/
To listen only the balun is not very important. You can use electician wire and "domino"
The basic formula for determining the wire length of a center fed, 1/2 wave wire dipole or inverted Vee antenna is:
143 ÷ freq(mhz) = Length(metres).
The inverted Vee antenna will be shorter by 2 – 5% depending on the angle from horizontal.
Dipoles have a feed point of about 75Ω in free space, and can be fed with 50Ω to 75Ω coax with or without a 1:1 balun. Inverted Vee’s present closer to 50Ω due to the effect of the ground being close to the tip of each leg. Feed your inverted vee with 50Ω coaxial cable, with or without a 1:1 balun. You can also feed with 300Ω or 450Ω balanced feeder into an ATU with balanced terminals. This will then work better as a multiband antenna.
https://m0ukd.com/calculators/inverted-vee-antenna/
https://www.qsl.net/wb4bxw/antenna_cal_dipole.shtml
If you transmit with an inverted V dipole antenna you must be careful with your CB radio or HAM radio transceiver
https://noji.com/hamradio/pdf-ppt/noji/Noji-Article-Protecting-Finals.pdf
