Ladder line-fed dipole and G5RV

With very few exceptions, every contact I’ve ever made has been with a dipole as the antenna. I use the term dipole loosley to include trap dipoles, fan dipoles, monoband coax-fed dipoles, the G5RV and my current antenna, a ladder-line fed dipole (which I’ll abbreviate here as LLFD).

I’ve used these antennas for the dual reasons of economy & simplicity and what follows is an explanation of why I’ve settled on the LLFD as opposed to the others.

First, here’s what I want in an antenna: cheap, easy to hang and good performance. I am primarily a DXer, so I define good performance as the ability to continually be adding new countries to the log on all HF bands – all with a single antenna.

Early on, I ruled out the “fan” dipole (too complex to erect for what it offers) and various flavors of trapped dipoles (too heavy and lossy for what it offers). Monoband dipoles are fine but…they’re monobands – I want a single antenna that I can use on all HF bands.

That leaves the G5RV and the LLFD.

In 1990, I bought a pre-packaged G5RV at a ham radio store in Newington, Connecticut. It was convenient, I didn’t have to cut, measure or solder. And it had a proven history as a performer, used by thousands – it wasn’t a gimmick antenna like the old Gothams.

When Louis Varney developed the antenna that would bear his callsign as its name, the HF bands consisted of 10, 15, 20, 40 and 80 meters. No WARC bands were even on the horizon at the time. Today, the G5RV is incorrectly touted as an all-band antenna for HF when nothing could be further from the truth (and it has been “iffy” on 10m from the beginning).

Yeah, it’ll tune 10, 17 and 30 meters. So will a 100w light bulb and a Cantenna.

Rather than re-write what’s been written, have a look at this analysis by W8JI. Halfway down is a chart showing feedline VSWR for a G5RV. A bit further down is another chart showing losses in dB incurred with those VSWR values. Pay particular attention to performance on 30 meters.

At this particular time in Connecticut, my one-of-a-kind Heath HW-9 (built beneath the Pacific Ocean onboard a nuke submarine) was loaned out to a fellow ham and my only remaining rig (try not to laugh) was a 30m one-watt Ramsey transmitter and a Magnavox D2999 receiver with BFO. And the G5RV, strung between oaks at my hilltop house in the appropriately named, Oakdale, CT.

So I was stuck on 30 meters with an antenna whose worst performance was on 30 meters.

At some point during these Navy shore duty years, a nor’easter took down the G5RV. The HW-9 loanee recommended an 80m dipole and his donation of enough 450-ohm feedline to mate antenna to Ramsey/Magnavox. I did, and the difference in performance was almost tangible.

No, I never had both antennas up simultaneously for A/B tests. And perhaps a better station would have disguised the difference between the two antennas. And a comparison on 20 meters would not have revealed much, if any, difference between them.

On the bands for which it’s designed, the G5RV delivers. My logbook from HW-9 contacts on bands other than 30m proves that, to my satisfaction. But it is not an all-band antenna, despite what the ads say and it was never intended to be.

More measured and graphed data on the G5RV is presented at this website, which concludes in part,

from a matching perspective, the G5RV is far from being an all-band antenna. With a modern in-built auto-tuner, it’s at best a 3-band antenna (80m, 20m, 12m). With a good external tuner it’s probably a 5-band antenna (80m, 40m, 20m, 15m, 12m). Other bands can be brought within matching range by incurring losses in the coax.

Of course by using a good external tuner and avoiding the coax section by bringing the ladderline all the way to the shack, losses will likely be acceptable on all bands 80m thru 10m ……… but is the antenna then a G5RV or simply a 102ft multiband doublet?

So the LLFD was selected based on sequential elimination of its competitors. Its main advantage is low feedline losses despite high SWR. Take a look at this page (halfway down) comparing losses of ladder line compared to various types of coaxial cable.

My LDG autotuner allows my 80m LLFD to present no higher than a 1.8:1 SWR to the rig. This is on 40 meters – other bands are 1.2:1 or less.

My current DXCC count with an 80m ladder-line fed dipole is 302.

.

.

  13 comments for “Ladder line-fed dipole and G5RV

  1. February 7, 2011 at 7:56 pm

    Thanks for the timely post, John! Almost like you were reading my mind. My G5 has seen better days and needs to be replaced this spring. Am thinking of perhaps an 88′ EDZ.

    Larry W2LJ

    • February 7, 2011 at 8:24 pm

      Better performing *and* less expensive than a G5RV…

    • Dr Bill Burton
      May 1, 2011 at 10:24 pm

      I have used the 88 foot EDZ on all bands from 80 to 10 m. It has worked well and has been used from many QTH’s with, in my case 600 Ohm balanced feeder. ( 6 inch centre to centre spacing 12 AWG wire).I have always used the system where one side of the antenna and the feedline are in one piece so eliminating soldered joints which can cause a break with much flexing. On 80 m the antenna performs well for NVIS operation I have never been able to get the antenna higher than 35 feet due to QTH limitations. Wire has always been 12 AWG stranded as I found that ordinary solid conductor household PVC covered wire broke after a year or so. Reminds me I did stretch the wire before erection. Secure one end and pull om the other with pliers. PROTECT YOUR EYES WHILST DOING THIS OF COURSE!!!!!!

      Used with a balanced tuner and not a balun.

      73 Rev Dr (Eng) Bill Burton DU3/G4CWA, T88BA, V73RJ ETC.

  2. February 8, 2011 at 6:06 am

    Hi John, I had a G5RV up for some time. It didn’t work for me, even the vertical with 1:9 balun at that time was better or equal on most bands. There are a lot of designs that use the same space and work a lot better especially on DX. 73, Bas

  3. February 8, 2011 at 11:01 am

    Ditto for my experience…the G5RV works well where it is supposed to. However, my “LLFD” -actually an Off-Center Fed Dipole- of 45’x90′- works much better everywhere. I feed it with 450 ohm window line in to a 6:1 current BALUN. Both antennas are up at the 40′ level.

  4. John K3TN
    February 10, 2011 at 7:27 am

    I’ve used a variety of wire antennas over the years, with lots of G5RV use, trap dipole, coax-fed dipoles, etc. both portable and fixed use at home.

    For my home use, coax feed is a must. That eliminates the LLFD at home. I used both ground mounted verticals and G5RV for many years, the G5RV was superior in 90% of use, with 40M DX being where the vertical was equal or better. I’m currently using a OCFD Windom and that out performs the G5RV, mostly because it is 35% longer. As far as tunability/losses, the G5RV is way superior on 10m compared to the OCFD, they are about equal on 17M (neither is great), the OCFD is much better on 30M than the G5RV.

    For portable use with a seperate tuner (ie, not built into the rig) with 135′ feet of room between supports, I’d go with the LLFD if center feed works.

  5. tony
    February 10, 2011 at 2:33 pm

    my granson is bulinding a elecraft k-3 100 while deployed to points unknow aboard a fast attack boat.

  6. February 10, 2011 at 5:14 pm

    I’ve been using ladderline fed dipoles/doublets, DEZ’s and loops as all band antennas for years with great results.

  7. AF6IT
    February 16, 2011 at 1:36 pm

    I enjoy my 450 ohm window line fed doublet. No balun and minimal loss. I homebrewed a Z-match which is so far as RF is concerned is slightly more efficient than any auto-tuner. Takes a tad more time & effort to tune, but I actually enjoy that aspect. (I’m not into contesting) Phil AD5X has a nice recipe for these on his website. I wish to keep my wires symmetrical to maximize balance in my modest system, thus have a personal aversion for OCF setups. But in any case playing with antennas is mighty good sport in my book- whatever the configuration. Soon as I can figure out how to support it I want to try a HOHP Loop as Thomas runs. Also extremely versatile but with a little less noise & less susceptible to static buildup.

  8. John Mullin
    June 24, 2013 at 10:12 am

    Hi John, don’t know if you received my previous posting or not. Why not try the G7FEK inverted L type antenna. Mine seems to work OK for me

    73
    John G0TEV

    • June 24, 2013 at 1:56 pm

      I’m not familiar with that antenna, John but will look it up.

  9. Lou Axeman
    September 12, 2013 at 9:13 am

    Just came across this and have to add my “two cents.” I live near the west border, and near the middle, north/south, of Saint Louis, MO on the first floor of a three story condo complex. In May, 2010 I installed a 200 foot dipole up 35 feet around the roof parapet of this complex fed with 450 ohm window line running up a shaft outside my laundry room/ham shack. I tune in with an MFJ-901B tuner, and lately also an MFJ-9211 4:1 QRPocket current balun. I have worked 58 DX entities with this setup using no more than 5 watts.

    • September 12, 2013 at 9:43 am

      It certainly makes for an efficient antenna. I cringe when I hear of new hams buying a G5RV when they could have a much more efficient antenna at a fraction of the price.

      We’re taught that “you get what you pay for” which is usually true – but not in this case. The cheaper ladder line-fed dipole is better than a more expensive G5RV.

Leave a Reply

Your email address will not be published.