Print

[K0OD]

In theory 5/8 wave verticals have a few dB gain over 1/4 wave ones at low radiation angles. Zero Five is selling monoband 5/8 wave verticals and the increasingly popular 43 foot multi-band verticals by Zero Five and DX Engineering are about 5/8 wave on 20 meters.

But how well do 5/8th wave HF verticals work in the real world?  

[WW5AA]

They work about as well as a 1/2 wave vertical, sometimes.

http://www.cebik.com/content/gp/58.html

73 de Lindy

[KB9CRY]

Like a vertical.

[W3LK]

FWIW, assuming the same radial installation and auto-coupler at the base of the antenna ...

A 43' piece of wire suspended from a tree limb or fiberglass pole will perform essentially the same as the multi-hundred-dollar pieces of aluminum that Zero-Five and DX Engineering are selling.

73,

Lon - W3LK
Naugatuck, Connecticut

[W5GA]

"A 43' piece of wire suspended from a tree limb or fiberglass pole will perform essentially the same as the multi-hundred-dollar pieces of aluminum that Zero-Five and DX Engineering are selling. "

Assuming you have a convenient tree, and can get a 1/4 mile roll of aluminum electric fence wire from a local farm store for about $19, your 43 foot vertical will cost about 61 cents, and you'll have LOTS of wire left to make radials out of.

73, Doug W5GA

[K0OD]

Let me repeat my question--my only question.

"But how well do 5/8th wave HF verticals work in the real world?"

--
Looking especially for hams who have used/tested 5/8 wave HF verticals against common antennas such as dipoles and 1/4 wave verticals. I mentioned ZeroFive and DXE to show that taller verticals are becoming far more common. 43 footers are only 5/8 wave (roughly) on 20 meters. Zero Five also makes a line of mono-band 5/8 wave verticals.  

[WW5AA]

I have built 1/4, 5/8 verticals and my conclusions are the same as Cebik's. You may want to register and read his very good desertation on 5/8 verticals. He can explain it better than I can. In my case, I found that in the real world there is no difference. I did A-B tests with a 5BTV and aluminum mast verticals (1/4, yes and 5/8) ranging in diameter from 2" to 1/2" on 40 meters and no one could tell the difference, including DX stations.

[W5CPT]

5/8ths Wave Verticals work only slightly better than 1/4 Wave but are much harder to match.

Clint - W5CPT

[N3OX]

"much harder to match. "

naaaah... you just need to arrange a little more wire in a coil at the bottom just right ;-)

I use close to a 5/8ths wave on 30m (same 60 foot vertical I use on 160m, 80m, 40m as well).

It works fine.  So did my 40 foot vertical coming in at .42 wavelengths.

I certainly can't tell the difference in my memory (no one can, unless the change is massive, like between a vertical and a beam) ...

I don't know that I'd go to the trouble of building a 5/8ths wave in particular because it does seem hard to realize a performance enhancement in the real world (though I do wonder sometimes about real world benefits of elevating current maxima above junk in the backyard)

But I use a 5/8ths wave because it won't work WORSE than a ground mounted 1/4 wave and it just happens to be a nice 1/4 wave on another band...  

The thing about real world comparisons of 1/4 wave and 5/8ths wave verticals is that the theoretical difference is just a few dB, the practical difference is probably a tad less, and reliably measuring a gain differential of, say, 2dB is really hard to do at home.

You'll notice that 2dB in the toughest pileups though... someone trying hard to pull you through on 20m would really love it if you gave them an extra 2dB signal to noise on their end.

If you really want to know the difference at your location, in your backyard, with your soil and ground clutter, you're going to have to build both and measure the field strength ...

73,
Dan

[K0OD]

How much is a dB or two worth in the real ham world? Actually it's a significant amount if you compare contest scores between high power, low power and QRP classes. 10db usually results in a huge difference and a tenth that is still significant.

Did some research on that question years ago and concluded a single dB added something like 10% to ones CQWW score. Tried to adjust for the fact that QRO stations tend to have better antennas than low power stations.

[N3OX]

Yeah, a "dB" is supposed to be a human-noticeable unit.

People like to claim that it doesn't matter because " 6dB is one "S-unit" " and who can tell the difference between S6 and S7 really?  

But I bet if you ran some tests with DXers (and especially with VHF/UHF weak signal guys) they could reliably tell you which signal was 1dB stronger than another when both were near the noise floor.

In fact, I wouldn't be surprised if I could do it.

So I think 1dB or 2db can certainly matter in a lot of DX situations.  2dB increase signal strength when the signal-to-noise ratio is already 28dB is meaningless.  When it's down near 0dB it means something.

Whether or not you'll actually GET any gain out of a 5/8ths wave vertical is a different matter though ;-)

73,
Dan

[K0OD]

I had researched stations that entered the CQWW in both high power and low power categories around the same period, presumably with about the same antennas. Not surprisingly, the difference in scores was huge with the amp on and off.

Whoever said a single db or two was "de minimis" surely wasn't a contester running a pile of JAs on 80 meters.

---------------

Back to 5/8 wave verts. I had one briefly years ago on 20 and found it to be worthless for stateside and not much better for DX.

Glad to see Lindy's comment:
"I did A-B tests with a 5BTV and aluminum mast verticals (1/4, yes and 5/8) ranging in diameter from 2" to 1/2" on 40 meters and no one could tell the difference, including DX stations."

Cebik isn't impressed with them and refers to the "5/8 Wave Vertical Mystique." I'm sure that mystique is helping ZeroFive and DXE sell their "43 footers."

I just put up a big DXE vertical and see nothing magical about its 20 meter performance.  But hard to tell yet for sure. Conditions stink.

[N3OX]

"no one could tell the difference, including DX stations." "

At least, not any DX station who you had good enough signals with to say "hey, can I run an antenna comparison?" ;-)

Only very careful stations could ever notice 2 or 3dB in on the air comparisons ... QSB can swing tens of dB after all.  If you actually had signal strength data (volts across a known audio load with the AGC off, perhaps), recorded over a long time on each antenna and averaged out the QSB, maybe it could be done... but it shouldn't work with casual A/Bing.

So it's an interesting conundrum.  You can't ever actually ASK anyone if one antenna is 2dB or 3dB stronger than another... but like we seem to agree on, that few dB probably helps quite a bit in a knock-down-drag-out pileup or when signals are very weak.  

As far as the mystique goes, well, I can say I've run a 40 foot vertical with matching networks at the base on 80 through 30m and you know what, I worked a lot of good DX on that:

http://www.n3ox.net/projects/lowbandvert

I sometimes wonder what people are comparing these things against where they get a night-and-day difference (especially when they're running a good 5dB feedline *loss* on a bunch of bands) but if you do it right, a 40-ish foot vertical fed efficiently will make you feel like you have a decent signal.

I didn't even have an amplifier.

What about 20m?  Well, if I can get an antenna up even 3/8ths wavelength I usually go horizontal.  I've tried verticals on the higher bands and they always disappoint me compared to a decently high dipole or whatever... but I've got a little beam for 20/17.

Dan

[K0OD]

My A/B tests are almost always on receive using my S-meter. (about 4.7 dB per S Unit).  Vastly more tests are possible as nets, pileups, long ragchews, beacons and foreign broadcast stations abound, especially on 20 and 40. CHU and WWV are convenient. Various modes. And, yes, testing on very weak signals can be done easily.

I've never seen a situation where the Transmit/Receive results weren't symmetrical.

-----------
Agree. I have no idea what some of the ZeroFive tests involve. For example, this endorsement: "99% of the time it is a 1st call antenna. The reports are outrageous. On 40 and 80 meters most reports are 20-30 over S-9." Pretty clear this guy isn't chasing central Asian stuff in the CQWW.  

Heck, the Zero Five, with more than 50 feet of coax,  stinks on 80 if you model it!

[W8JI]

How much is a dB or two worth in the real ham world?>

Nothing at all really.

 <<Actually it's a significant amount if you compare contest scores between high power, low power and QRP classes. 10db usually results in a huge difference and a tenth that is still significant.>>

Ten dB is a lot, but 1 dB is not. No one will really know about 1dB, in a contest or not.

<<Did some research on that question years ago and concluded a single dB added something like 10% to ones CQWW score. Tried to adjust for the fact that QRO stations tend to have better antennas than low power stations.>>

That is a seriously flawed study and conclusion as anyone who understands such studies would understand.

We cannot extrapolate and sort a difference of one dB in transmitter power when the antennas are different, the feedlines are different, the equipment is different, the operators are different, the locations are different, and so on.

I can tell you first hand we can change power here 3 dB and not see any detectable change in QSO rate. The only change is when working staions that marginally hear us, either from heavy QRM or because we are weak. I've looked at logs when we had to use a backup amp and the rate is unchanged.

As for the 5/8th wave, I would never use one. I have a 5/8th wave vertical on 160 meters. In blind A-B tests it is insignificantly different than a 1/4 wave at distance more than 1000 miles. From maybe 250 to 1000 miles it is a few dB WEAKER, and right in close it is a few dB better.

160 is actually a band where the better earth conductivity makes a 5/8th wave have a chance at being better.

Now you might see a change on 20 and higher from the antenna clearing ground clutter better, but that's something you would have to determine with an A-B test. My experience in Ohio was a 1/4 wave antenna at 150 feet AGL was better than a 5/8th wave on 20 meters.

What was I doing? I had a 5 element 20 at 140-150 feet. When I would work Europeans the W4's and W2's would come on for schedules and just start talking. So I ran some tests with Europeans to find a good antenna, and concluded a 5/8th was not worth the wind problems. Compared to the Yagi either was equal.

To stop the W2's from working the W4's in schedules while I was using a frequency, I would transmit on the vertical and only use the Yagi for receiving.

I was about 8-9 dB weaker on the vertical, but I worked just as many Europeans as I could when I used the Yagi and the W4's never came on and bothered me after that.

Seriously, who cares if someone is 20 over nine or 30 over nine?  If I was only S5 it would have mattered a little more, but not when signals were good.

Don't get sucked into that 1dB=10% more QSO's stuff. The study is so seriously flawed it is meaningless. If they wanted to do a good study they would have had to use one station and one operator and varied the power every few minutes and looked at the rate.

Contesters go way overboard with signal level, when what really makes a big difference is an accumation of many things....90% of which is location, receiving, and the operator.

73 Tom