Which One Makes Sense? G5RV, Cobra Ultralight or W7FG True Ladder Line All Band Doublet
I get asked this question all the time, especially at ham fests that I attend. Last night I presented a talk at one of our local club meetings about ladder line and open wire doublets.
Guess what? Many of the newly licensed General’s had G5RV’s and one had a Cobra Ultralight. A couple of hams bought a ready-made, coax-fed 20 meter dipole. So, I get asked “if these antennas aren’t really all that great, why do so many hams use them”?That’s an easy question to answer. They are sold everywhere. They are in all the catalogs, magazines, flea markets and, they promise a lot of things to the new ham such as “most popular, hang and play™, high performance, booming signal, completely assembled, 300% power gain, full legal limit, heavy duty…………” You get the picture. I could fill this page with claims.
If you watch any of the back and forth arguments on forums, the G5RV is the “BEST” and the “WORST” antenna, all at the same time. The Cobra Ultralight is in the same camp. BOTH of these antennas are a “compromise” solution to erecting an “effective”, multiband antenna for HF. If the hams that post on the forums were to take part in a cage fight, live and in person, they’d fight each other to the death over the virtues of both sides of the argument.
Here’s a link to the wayback machine article which details the drawbacks of the Cobra Ultralight. Note that links and images are missing from archived pages. You won’t need the images.
Both of these antennas are fed with 450Ω “window line” which is much more susceptible to SWR swings and loss, especially when it rains or snows. If you’re on the air and it starts to rain, check your transmatch and retune. Open wire, 600Ω, True Ladder Line, does not require retuning under this condition. That’s a basic fact. Check out this PDF file of the U S Air Force MARS training document and go to page 127. I think you’ll agree that this backs up my statement.
Open wire-fed doublets have been around since the earliest days of amateur radio, well before World War II. Early radio books as far back as 1930 have plans and details for open wire line. Even broadcast stations used it. That’s all there was! It is a tried and true, proven concept.
I am on the air quite often, mostly 75m AM phone and sometimes 20m SSB to work a couple of friends in other parts of the world. I hear quite often that pretty much 100% of the stations these guys run, which are either old boat anchors, military gear, homebrew, high-power, Class E rigs as well as some of the Flex SDR’s, ALL run open wire line! Why do they use this antenna, almost exclusively? It’s easy, cheap, and efficient and it simply works. It has no connection parts, wire clamps; solder joints, crimp- on connectors, window line to coax transition points or anything that will eventually fail on the worst weather day. If installed properly, nearly 98% of the power output is radiated.
Now, here’s what convinced me, well before owning this business. Guess what antenna I started out with? A G5RV! I was a newly minted General back in the early 80’s and followed the same path. Then an expert and well-known ham author, told me to “tear down that junk and put up an open wire fed doublet”. At the time, I was busy traveling all over the US, installing, servicing and doing training classes for a prominent semiconductor equipment company. I didn’t have time to build one. I discovered W7FG Vintage Manuals, who was selling the doublet, and ordered a 10-80 x 100’ from Gary. All I can say is “WOW”. What a difference it made. After talking to the same friend on the West Coast but with the W7FG doublet, he asked right away if I was running my amp. He said “I told you so”. I got it!
Hams are always posting on the antenna forums the fact that their G5RV or Cobra Ultralight worked stations into Europe with a 5x9 report. Sure, I can do that with a vertical whip as well. Repeatedly? Probably not.
Here’s what I tell people that sums it all up with a bottom line statement. With either a G5RV or Cobra Ultralight, you have to purchase a decent tuner anyway just to get on the air. Most internal tuners will choke on either of these antennas. That’s a known fact. So, rather than spend money on any antenna that’s a compromise, why not just get one that’s been proven for decades with thousands in use all over the world?
Finally, many of my customers tell me the reason they purchased a True Ladder Line Doublet is because they took down their G5RV or Cobra Ultralight and are enjoying the increased receive strength, less noise and static and a much better signal out. I have yet to hear that scenario in reverse. If you know of anyone that took down a True Ladder Line doublet to put up a Cobra Ultralight or G5RV, I’d love to speak with them.
Give one a try. I promise you won’t be disappointed!