A group of us were sitting around a table at the local pizzeria, hashing out the details for the upcoming Field Day. Next on the agenda was antennas—and everyone had an opinion.
After a few minutes of animated discussion, one of the guys got all fired up about the G5RV dipole. “G5RV, best dang antenna I’ve ever used,” he bragged. Then we heard a long testimonial about how he’d set one up in his parents’ attic and worked a ton of DX, how he still uses them to this day, and how they’re the perfect antenna for working all bands. Some were not amused, others shook their heads, and a few actually agreed with him.
Love them or hate them, G5RVs have a loyal following—and a lot of critics. Is it your best choice?
What is a G5RV Antenna
First, let’s look at the history of the G5RV. Louis Varney, G5RV, invented the antenna in 1946 after leaving the military. Like other Hams, he was anxious to get on the air following the WWII ban on Amateur Radio operation. He’d been thinking a lot about an antenna that would work on all the HF bands and fit his small yard in Buckinghamshire, England.
The antenna Varney built met his expectations and soon other amateurs started using it with good results. In 1958, the RSGB Bulletin published his article, “An Effective Multi-band Aerial of Simple Construction.” Soon, the G5RV became a part of Amateur Radio folklore.
Note that the G5RV is a variation of a dipole which is 102 feet long and matches best on 20M—the 102 foot length is three half-wavelengths at 14 MHz. To make it usable on other bands, Varney added a 34 foot (half wavelength at 14 MHz) tuned feeder constructed of 450 ohm ladder line that behaved as a matching device.
Originally, the G5RV was used with tube rigs that would match a wide range of impedances using the plate/load tuning controls. Tubes were tolerant of mismatches, unlike today’s solid-state transceivers that balk at anything over 2:1. And the only bands used at the time were harmonically related, theoretically making matching chores a little easier. None of the WARC bands were yet available, which complicates matching today’s G5RV.
Looking at functionality, 80M and 40M had moderate VSWR readings. Varney admitted all along that the G5RV worked best on 20M, but he recommended the use of a tuner on the other HF bands in a 1984 article published in Radio Communications. Hams continued to swear by the G5RV antennas, but they weren’t (and still aren’t) a miracle solution to all-band operation.
In an attempt to improve the VSWR figures, some commercial vendors supply the G5RV with a long length of relatively lossy coax, typically 70 feet. This tweaks the operation of the antenna, reportedly making it easier to match with radios that have built-in auto tuners. Some even added baluns or chokes.But the fact remained that high VSWR figuresand losses would still yield mediocre performance on some bands.
G5RV Alternatives
There are other dipole choices that will likely work better. This may come as a shock to many, but it’s true.
In the mid-1980s, Brian Austin (ZS6BKW) ran computer analysis to develop an antenna system that would match the maximum number of HF bands possible without an antenna tuner, using 50-ohm coaxial cable as the main feed line. His ZS6BKW multiband antenna took the original G5RV and adjusted the length of the radiators and ladder line matching section. It provides a reasonable match on five bands: 40, 20, 17, 12 and 10 meters without a tuner.
Doublets are one of the oldest and least expensive Ham antennas around. The all-band doublet antenna is nothing more than a 1/2 wave dipole cut for your lowest operating frequency and fed with twinlead, ladder line, or open wire. It requires a tuner but is efficient and very frequency flexible. A single band dipole fed with coax (preferably with a 1:1 balun) is remarkably efficient and effective.
The trap dipole and parallel dipole are options to provide resonant antennas on multiple bands without a tuner. Traps are tuned circuits that act somewhat like automatically switched inductors or capacitors, adding or subtracting from the length of the antenna according to the frequency of your signal. The parallel dipole uses several dipoles joined together in the center and fed with the same cable. Alpha Delta antennas use a hybrid approach which has both parallel dipoles and coils instead of traps.
Another alternative is the off-center fed dipole (OCF). The performance is very good across the HF bands and requires little or no tuning. By moving the feedpoint away from the center and adding a 4:1 or 6:1 balun, you can cover a number of HF bands. Buckmaster’s OCF 80 covers 80/75, 40, 20, 17, 12, 10, and 6 meters.
Although some claim the popular G5RV antenna works well on all bands, 80 through 10 meters, that is not the case. This is not to say that the G5RV doesn’t work well on some bands—but it’s not a magic solution for multiband HF operation.
