Editor’s Note: Over the next several months, OnAllBands will be featuring a series of articles from Harry “Trippy” Brown, AC8S, longtime amateur operator and antenna builder/tester who’s never let his visual impairment stop him from enjoying the hobby he loves. As the title of this series states, we hope these articles provide you with invaluable insights as you pursue your own successful antenna projects.
In our continued look at the benefits of using dipole/inverted-V combo antennas and insight on how to build them, I’ll be answering a few more frequently asked questions in today’s blog post. To read the first six entries in this series, just enter “Trippy” in the OnAllBands search box above.
What are some of the lengths of dipole/inverted-V combos and end-fed antennas that have been tested by hams? What were the results?
Note: The following lengths do not include the 3 inches on the end of each leg of the dipole/inverted-V combo or the 3 inches at the end of the leg of the end-fed antenna. Unless otherwise indicated below, these lengths have proven to work great for both end-feds and dipole/inverted-V combos:
- 29 feet works fantastic, tuning 40 through 2 meters but not 80 meters.
- 34 feet, four inches is a quarter wave on 40 meters; it tunes 40 through 2 meters as a dipole/inverted-V but not as an end-fed (I have a friend who tried this length as an end-fed on his balcony, and it did not get out).
- 35 feet, six inches works fantastic, tuning 40 through 2 meters.
- 39 feet works fantastic, tuning 40 through 2 meters. I have a friend who had one of this length on his balcony, and the SWR when the two legs of the dipole/inverted-V combo were dropped straight down at a 90 degree angle (totaling 180 degrees) was below 2 to 1 on all bands—40 through 10!
- 41 feet tunes 40 through 2 meters, with an antenna efficiency of 66% (66 out of 100 watts will be transmitted).
- 43 feet works great, tuning 80 through 2 meters.
- 44 feet works fantastic for both antennas, tuning 80 through 2 meters, with an antenna efficiency of 71% on 80 meters.
- 51 feet is fantastic, tuning 80 through 2 meters with an antenna efficiency of 82% on 80 meters.
- 53 feet works well with both antennas, tuning 80 through 2 meters with an antenna efficiency of 68% efficiency on 80 meters.
- 58 feet is fantastic, tuning 80 through 2 meters.
- 59 feet is great, tuning 80 through 2 meters with an antenna efficiency of 94% on 80 meters.
- 60 feet is fantastic, tuning 80 through 2 meters with an antenna efficiency of 96%.
- 61 feet works well with both antennas, tuning 80 through 2 meters.
- 65 feet, six inches is a quarter wave on 80 meters, tuning 80 through 2 meters.
- 71 feet and 72 feet work well with both antennas, tuning 80 through 2 meters.
- 84 feet tunes 160 through 2 meters. It can be used for both the dipole/inverted-V combo and the W3EDP end-fed. If you’re using it as an end-fed, your coax must be no more than 17 feet. If you want 20 meters to be one of the covered bands, W3EDP found that although the 17-foot counterpoise worked well on most bands, a length of 6 1/2 feet “seemed to outshine all the others” as the counterpoise on 20 meters, so I would just use the 6 1/2 foot counterpoise.
- 88, 88.5, 98, 98.5, and 107 feet work well, tuning 80 through 2 meters.
- 110 feet works fantastic for both antennas, tuning 80 through 2 meters. You can use this length as an end-fed with no less than 22 feet, 3 inches of coax as your counterpoise. (My thanks to Mike, WA7ARK, for his info about how long the coax should be for this length of antenna).
- 119, 124.5, 125, and 127 feet are fantastic for both antennas, tuning 80 through 2 meters.
- 130 feet is fantastic, tuning 80 through 2 meters. You can use it as an end-fed, but you must have 100 feet of coax that goes from the radio to the unun.
- 131 feet, six inches works for both antennas, tuning 80 through 2 meters.
- 131 feet, 8 inches is fantastic, tuning 80 through 2 meters. I have a
friend who uses this length of antenna, and his SWR is 1.7 to 1 or lower across the entire 80 meter band! - 132 feet and 133 feet work well with both antennas, tuning 80 through 2 meters. Note: Randy, K5NJE, a new ham, uses 133 feet for his end-fed. People think he’s running an amp, but he’s only using 100 watts and 60 feet of coax. He told me in an email: “I’ve come in 5S units stronger to England over other people running 1.5 kW. I step over people all the time, and some are really shocked to hear I’m just running barefoot.” So if you’re using this length as a half wave end-fed, use at least 60 feet of coax.
- 135 feet, six inches, 140, 146, 148, 162, 175, and 203 feet work with both antennas, tuning 80 through 2 meters.
- 240 feet works great, tuning 160 through 2 meters.
- 262 feet, 4 inches is FABULOUS, tuning 80 through 2 meters. It’s a 1 wave on 80 meters, just above a 1 and 91/100ths wave on 40, almost a 4 wave on 20, almost a 6 wave on 15, almost an 8 wave on 10, and just under a 13-and-a-half wave on 6. I use it as a dipole/inverted-V combo and it works great with only 15 watts from my balcony (only 8 feet off the ground) using my Elecraft KX3. I made many CW contacts, even reaching a Rhode Island station on 40 meter SSB in July 2021. That was my first-ever out-of-town SSB contact from my apartment on 40 meters. I also worked four 20 meter SSB contacts during the IARU HF Championship in July. And I worked a 6 meter SSB contact during the CQ Worldwide VHF contest the same month using 10 watts!
- 347 feet is fantastic, tuning 160 through 2 meters.
- 525 feet is great, tuning 160 through 2 meters.
Here’s a list of tested antenna lengths that did not work for all-band dipole/inverted-V combos (not including 3 inches on each leg) and end-feds (not including 3 inches at the end of the leg):
24 feet: did not tune on any band, even with an antenna tuner
36 feet: did not tune on any band, even with an antenna tuner
66 feet: did not tune on any band, even with an antenna tuner
117 feet: did not tune on any band, even with an antenna tuner
128 feet: produced an SWR of 10.3 to 1; did not tune on any band, even with an antenna tuner
328 feet, 6 inches; 394 feet; 406 feet, six inches; 407 feet, 6 inches; 423 feet, 6 inches; and 518 feet, 3 inches all did not work.
In my next blog post I’ll be answering more questions about building dipole/inverted-V and end-fed antennas. Stay tuned!
