(click on image to enlarge)

The W6SAI version of the G5RV antenna
Dr. Brian Austin, ZS6BKW, aided by a computer program and fields tests, varied dimensions of the G5RV design, trying to achieve a reasonably low value of SWR response on all major HF bands.
Bill Orr,W6SAI, built another version. He found he had to add 6 inches to the original BKW line dimension to get best results. Also, a 1-to-1 current balun at the bottom of the line is a necessity. Ferrite beads should be used to "cool off" the coax line. As with the earlier G5RV design, physical placement of the coax line and its length can determine the SWR at the transmitter. The ribbon line can be trimmed for best results on one band. Once the dimensions are adjusted for your particular installation, you will find this a very satisfyling antenna.
The G3TKN multiband antenna for 10, 18, 24 MHz 
Have you operated the WARC bands? If you don't have an antenna that will do the job, consider a simple and effective design by V.C. Lear, G3TKN/VO1XG. This sky-wire is inexpensive, easy to build, and should require no antenna tuning unit (ATU) in most instances.
On 10 MHz band, the antenna operates as two half-waves in phase, providing a figure-8 pattern slightly narrower than a dipole, with about 0.75 dBd (2.9 dBi) gain. On 18 MHz, the antenna is nearly three half-waves, center-fed, showing six lobes, with about 0.5 dBd (2.65 dBi) gain. On 24 MHz, each antenna leg is about one wavelenght long. The radiation pattern shows four lobes, with a power gain of about 1.7 dBd (3.85 dBi).
The G8PO triangle sloper for 80 meters
To boost his long-path signal, Ted Ironmonger,G8PO, converted his sloper into a triangular antenna. Total length of wire in the new antenna is approximately a half-wave. The antenna is coax-fed at the apex, with one leg running down adjacent to the tower. The other leg acts as the sloper wire, with the end folded back to conserve space. Directivity is in the direction of the sloping wire.
The lengths are given as a guide, and overall length and spacing to ground and the tower (points 1, 2, 4 and 4a) can be adjusted for lowest SWR. End spacing and length (point 3) also allows SWR adjustment.G8PO used a half-wave of coax line (about 88') to the shack.
Ted noted the simple triangle sloper gave much improved results over his old antenna.