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[Articles Home]  [Add Article]  

The 43' Vertical -- a Theoretical Analysis

DAVE CUTHBERT (WX7G) on March 28, 2009
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The 43' Vertical - a Theoretical Analysis

Dave Cuthbert, WX7G

Introduction

The subject of the 43 foot vertical comes up from time to time on the eham forums and the AntenneX forum. These forums contain lots of estimates, guesstimates, and qualitative pronouncements of expected performance and feed methods. In this article we will examine this interesting antenna to obtain quantitative data that you can use to make decisions about this antenna.

We will cover:

Input impedance

Radiation patterns

Feed methods

Feedline loss

Ground loss

Comparison to ¼ wavelength verticals

What We won't cover:
Additions, modifications and other improvements

Analysis Method

The antenna was analyzed using EZNEC NEC-2 software. The impedance measurements were done with the antenna mounted over PERFECT REAL GND. The radiation patterns of Fig. 9 and Fig. 10 were done with the antenna base mounted 1' over REAL GND, 16 radials, and 15 ohms of base loss resistance added. The comparison radiation patterns of Fig. 11, 12, and 13 were done with the antenna connected directly to MININEC GND.

Impedance and VSWR

Fig. 1 is the VSWR obtained over perfect GND. This is essentially what an antenna tuner mounted at the antenna base will see.

0x01 graphic

Fig. 1 50 ohm VSWR, Direct feed

Users of this antenna often feed it directly with 50 ohm coax or through a 4:1 unun and run 50 ohm coax to an antenna tuner at the shack. The VSWR for thE 4:1 unun case is shown in Fig. 2.

0x01 graphic

Fig. 2 50 ohm VSWR, 4:1 Unun feed

And a few potential users have asked about feeding the antenna directly with 450 ohm line to an antenna tuner at the shack. The VSWR is shown in Fig. 3

0x01 graphic

Fig. 3 450 ohm VSWR, Direct Feed

Feedline Loss

Feedline loss can make or break the performance of this antenna. The direct-fed loss of 75' for various types of coax and ladder line are shown in Table 1. The most common feedline, RG-213, is shown in blue. Losses are tolerable on the 40 - 10 meter bands with 80 meters a useable 6.5 dB. LMR-400 is a bit better with the very large and very expensive Andrews LDF5-50 exhibiting low losses on 80 - 10 meters. Surprisingly the rather inexpensive 544 Ladder line available from The Wireman™ exhibits even lower loss.

Table 2 shows the line loss when an ideal 4:1 Unun is placed between the antenna and the line. The 4:1 unun offers slightly reduced line loss and provides a better VSWR for the shack located antenna tuner to work with. The VSWR the antenna tuner must contend when the antenna is fed through a 4:1 unun and 75' of RG-213 coax is shown in Fig. 6. Note that the line loss reduces the VSWR seen by the antenna tuner.

Direct feed line loss

Band

RG-8X

RG-213

LMR-400

LDF5-50

554 LADDER

1.8 MHz

20 dB

18 dB

15 dB

9.6 dB

6.6 dB

3.5

9.2

6.5

5.7

2.4

1.6

7

2.0

1.3

0.8

0.2

0.2

10.1

5.0

3.1

2.6

0.9

0.14

14

5.4

3.5

2.8

1.0

0.48

21

4.6

3.1

2.3

0.8

0.15

28

1.5

0.8

0.5

0.2

0.6

Table 1

4:1 Unun feed, line loss

Band

RG-8X

RG-213

LMR-400

LDF5-50

1.8 MHz

17 dB

15 dB

12 dB

7.3 dB

3.5

6.9

4.4

3.9

1.5

7

1.3

0.8

0.5

0.2

10.1

3.7

2.1

1.8

0.7

14

5.2

3.2

2.6

0.8

21

2.8

1.7

1.2

0.4

28

1.7

0.9

0.6

0.2

Table 2

0x01 graphic

Fig. 6 VSWR, 4:1 XFMR, 75' RG-213 COAX

Ladder Line Feed

The mention of ladder line - a balanced line - to feed this unbalanced antenna elicits alarm from some forum members. Admittedly there is feedline radiation as well as increased line loss due to the line being near lossy GND.

While this EZNEC model is not ideal, it does give us an idea of how significant ladder line radiation is. The EZNEC model is a 43' vertical fed with 75' of ladder line. The ladder line consists of two #12 copper wires spaced 2 apart. This is equivalent to 554 ladder line in both impedance and loss. The ground used is MININEC with the antenna driven against GND.

Fig. 7 and Fig. 8 are Azimuth plots of the vertical fed directly and then with the vertical fed with 75' of ladder line. The ladder line does contribute to the antenna radiation, causing some fill-in of the radiation pattern. The contribution due to the ladder line does not appear to be harmful to performance.

0x01 graphic

Fig. 7 Direct Feed and Ladder Line feed

0x01 graphic

Fig. 8 Direct Feed and Ladder Line feed

Feedline Data

The feedline data used for the simulation is shown in Table 3 and was obtained from sources listed under references.

Loss

RG-8X

RG-213

LMR-400

LDF5-50

554 LADDER

50 MHz, matched

2.5 dB

1.3

0.9

0.25

0.28

VF

0.78

0.66

0.85

0.88

0.91

Table 3

Radiation Patterns

The radiation patterns of this antenna can be frightening on the higher bands, as seen in Fig. 10. The low band radiation patterns are quite nice, as seen in Fig. 9.

0x01 graphic

Fig. 9 3.5 MHz, 7 MHz, 10.1 MHz

0x01 graphic

Fig. 10 14 MHz, 21 MHz, 28 MHz

Comparison to ¼ wavelength Verticals

An alternative to the 43' vertical is a trap vertical or a monoband vertical. The following radiation plots compare the 43' vertical to a ¼-wavelength vertical on 20, 15 and 10 meters, the bands where the 43' vertical exhibits substantial high angle radiation.

On 20 meters the 43' vertical has more radiation at take-off-angles of 25 degrees and below.

0x01 graphic

Fig. 11 43' vertical, ¼-wavelength vertical

On 15 meters the 43' vertical is only slightly inferior to a the ¼-wavelength vertical at take-off-angles below 15 degrees.

0x01 graphic

Fig. 12 43' vertical, ¼-wavelength vertical

On 10 meters the 43' vertical is down by 5 dB at a take-off-angle of 10 degrees.

0x01 graphic

Fig. 13 43' vertical, ¼-wavelength vertical

Ground Losses

The ground loss of a vertical antenna is heavily dependent on the antenna base current. As shown in Table 4 the resistive part of the base impedance is fairly high on 40 - 10 meters with the minimum being 90 ohms. Just a few 25' ground-mounted radials will bring the ground loss resistance below 50 ohms, producing an antenna efficiency of 65% or more. 160 and 80 meters are a different story and these bands will benefit from a good radial system.

Band

Base impedance

1.8 MHz

18 - j700

3.5

28 - j260

7

90 + j150

10.1

900 + j700

14

110 - j300

18.1

110 + j75

21

370 + j360

25

180 -j350

28

97 - j30

Table 4

Conclusions

Although the performance of the 43' vertical has been quantified it is still open to interpretation. Where one might say 2 dB of line loss is acceptable another might say it is intolerable. So, I'll give my own qualitative take on this antenna.

The radiation pattern is quite good up through the 15 meter band. The line loss is not excessive when loss-loss coax is used. Whether to feed directly or through a 4:1 unun depends on the tradeoff between unun loss and antenna tuner loss. This we have little data for. Overall, this is an attractive antenna that competes in performance against trap verticals and monoband verticals.

References

The RF Connection, Cable data, http://www.therfc.com/coax.htm

Orchard City Amateur Radio Club, Line Loss Calculator, http://www.ocarc.ca/coax.htm

Member Comments:
This article has expired. No more comments may be added.
 
The 43' Vertical -- a Theoretical Analysis  
by W8JI on March 28, 2009 Mail this to a friend!
While it is commonly done, we can not measure or estimate ladder line radiation nor the effects of ground in a model like that. The model will be wrong.

To do it accurately we have to have a source that represents real source with reasonable source common mode impedances, and the analysis has to be a near-field analysis.

Far field pattern distortion does not tell us much, if it even tells us anything useful at all.

Beasley made this same mistake years ago in an analysis of a Zepp antenna. The model "proved" feedline radiation was negligible. As in this case, he used a "perfect" ground independent current source with infinite common mode impedance and looked only at the far field pattern. If we look at a Zepp with an appropriate source in the near field, which is really where all the problems are, we find feeder radiation is significant for any reasonable feeder length. There is also the potential for significant common mode voltage or current at the source.

It is never a good idea to feed an unbalanced load with a balanced source, but the only way to prove it is to use the CORRECT model and the important analysis points, which are in the near field....not miles away.

We should also include transformer losses and matching losses.

73 Tom
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N2EY on March 28, 2009 Mail this to a friend!
A couple of points:

1) Seems to me that this is really just a vertical version of the 88 foot dipole depicted on W4RNL's site and elsewhere.

2) I think the best approach is a remote tuner at the feedpoint. The feedpoint Z on most bands is such that a simple L network should do the job. This would permit the use of inexpensive coax operating at low SWR.

3) I agree with W8JI that the use of balanced line results in a highly inaccurate model.

4) It would be interesting to see the results if a 1:1 or 1:4 balun were installed at the feedpoint and ~400 ohm balanced line used (unbalanced side to the antenna, of course).

5) What about the use of cable-TV hardline instead of 50 ohm coax?

73 de Jim, N2EY
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N4LQ on March 28, 2009 Mail this to a friend!
Thanks. Nice job. This answers a lot of questions about the mysterious 43' vertical but leaves a few unanswered questions about the equally mysterious 4:1 balun/unun.
 
The 43' Vertical -- a Theoretical Analysis  
by HFRF on March 28, 2009 Mail this to a friend!
I am not sure what the author thinks he is accomplishing with this "article". Everything he writes is based on an antenna simulator running on a computer and not one piece of actual measured data from a real antenna is provided. He puts a lot of faith in computer software with a million assumptions implied. He also generates a comparison of different antennas by simply looking at their assumed swr. My dummy load must be a very good antenna since its swr is always 1:1.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by HFRF on March 28, 2009 Mail this to a friend!
Another small observation that causes much amusement is when hams seem to always equate physical symmetry with electrical balance. It seems anything that looks physically symmetrical must be electrically balanced like ladder line, and if something looks physically unsymmetrical it must be electrically unbalanced like coax.

Can someone prove that this is always the case? Intuitive judgments are almost always wrong.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N2EY on March 28, 2009 Mail this to a friend!
HFRF writes: "I am not sure what the author thinks he is accomplishing with this "article"."

Just what the title says: a Theoretical Analysis.

HFRF: "Everything he writes is based on an antenna simulator running on a computer and not one piece of actual measured data from a real antenna is provided."

What's the problem with any of that? It's a THEORETICAL analysis, nothing more. All real engineering starts with a theoretical analysis of the problem.

It would be great if someone could set up an antenna range and measure the exact fields of various amateur radio HF antennas. Trouble is, very few of us have anything like the resources needed for it. So a simulator is the next best thing.

HFRF: "Another small observation that causes much amusement is when hams seem to always equate physical symmetry with electrical balance. It seems anything that looks physically symmetrical must be electrically balanced like ladder line, and if something looks physically unsymmetrical it must be electrically unbalanced like coax."

Why wouldn't that be valid? By definition, true physical symmetry causes electrical symmetry.

Why would an antenna or transmission line that was truly physically symmetrical be electrically unbalanced?

73 de Jim, N2EY


 
RE: The 43' Vertical -- a Theoretical Analysis  
by K5UJ on March 28, 2009 Mail this to a friend!
<<<1) Seems to me that this is really just a vertical version of the 88 foot dipole depicted on W4RNL's site and elsewhere. >>>

Yes and no. In the loose sense that it is a fixed length attempt to cover a bunch of bands then yes.

There are important differences. A center fed 88 foot dipole is a balanced antenna and can be easily fed with parallel wire feedline and have that balanced Z transformed to 50 ohms unbalanced near the ham shack with very little balanced line loss, and a better chance of getting more of the power delivered to the load (feedpoint) radiated. Assuming the center fed dipole is horizontal and reasonably high, there will be minimal ground loss relative to the monopole vertical (given the typical ham ground system) and at higher frequencies where the antenna starts to become directional, at least the lobes will be lower angle. With the vertical, these same high frequency lobes where 43 feet starts to be longer than 1/2 w/l will go up at high angles. With the dipole you may also have less noise pickup on receive and no common mode RF problems.
 
The 43' Vertical -- a Theoretical Analysis  
by K9WJL on March 28, 2009 Mail this to a friend!
As a user of the 43' Zero five, I appreciate the Author's analysis, and the extensive modeling. I find it informative, especially the feedline loss section. it's very revealing to me. After using the antenna for a little over year now, his model and assumptions seem to be similar to what I see in it's use. I don't use mine much on 80 or 160. My OCF dipole whips it pretty good.
I'll be shopping for some heliax though to improve the feedline loss.
I'd like to see more than 16 radials though. I'm running 54 totaling about 2500' of wire.
Thanks for the great article,
73,
Bill K9WJL
 
The 43' Vertical -- a Theoretical Analysis  
by N0AH on March 28, 2009 Mail this to a friend!
I used 43 foot verticals with addtional 15 foot top hats (3) to make antennas for 80M. Very fb- Not sure what I would do with a single 43 foot vertical without further modifications. Nice ideas here but isn't this why we have antennas like the Hustler 6BTV to cover a lot of bands with one vertical in the back yard?
 
RE: The 43' Vertical -- a Theoretical Analysis  
by K6AER on March 28, 2009 Mail this to a friend!
Tom, W8JI, had alluded in his last statement to transformer losses. In specific the loss of a 4:1 Balun running high power with a high VSWR. The losses could be as high as 10-15 dB depending on the heating and coax loss.

Also with the antenna mounted on the ground how do you feed the antenna with a balanced line with out differential currents coupling to your radials. If the feed system is elevated you now have the antenna feed in the near field pattern.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on March 28, 2009 Mail this to a friend!
I also want to know about real transformer losses ...

 
RE: The 43' Vertical -- a Theoretical Analysis  
by HFRF on March 28, 2009 Mail this to a friend!
I really see no need to continue a discussion that will lead nowhere, but here goes.

According to N2EY:

"Why would an antenna or transmission line that was truly physically symmetrical be electrically unbalanced?

73 de Jim, N2EY"

Consider these scenarios:

1. Would a piece of twin lead that ran perpendicular to a metal pipe or any metal surface, be unbalanced or balanced? What if the twin lead was flat along the metal surface? What if the twin lead ran with its surface perpendicular to the metal surface with one side closer to the metal than the other conductor? Disregard any other effects that don't have anything to do with balance or unbalance of the transmission line.

2. What if one side of a piece of twin lead was terminated to vertical radiator and the other conductor of the twin lead was left open at the ground connection of the vertical but there was significant capacitive coupling to ground along the run of the twin lead? What if the twin lead end that was left open did not have any capacitive coupling to ground but you could consider significant coupling from one wire of the twin lead to the other and what if the twin lead transmission line was exactly an electrical 1/4 wavelength?

3. How would a transmission line constructed from 2 pieces of coax each exactly 1/2 wavelength long (taking into account velocity factor) behave, if the coax was connected together but the center of the total length had the center connection where the center conductor of one piece was connected to the ground of the other piece of coax and the same with the other shield and ground. Would the line as a whole act as a balanced or unbalanced transmission line? What if the 2 pieces of coax were exactly 1/4 wavelength long each? Would the composite transmission line behave as an unbalanced line as seen from the far ends or would it look like a balanced line?

4. How would a piece of coax behave (balanced or unbalance) if a stray wire like a long ground wire on a telephone pole absorbed strong radiation from a Yagi and re radiated a strong EM wave to the transmission coax line? What if the coax was twin lead? Would the actual location where the transmission line intercepted the EM wave affect balance for either coax or twin lead?

5. If you used a piece of coax as a stub would it work differently than if you used balanced line like twin lead? Would it determined how the stub was used (as in the length of the stub)?

I could go on all day with this but I would like N2EY to answer these questions since he said that only the physical symmetry determines if a transmission line behaves as balance or unbalanced.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N2EY on March 28, 2009 Mail this to a friend!
N0AH writes: "isn't this why we have antennas like the Hustler 6BTV to cover a lot of bands with one vertical in the back yard?"

I think there's a basic difference between the two.

A trap vertical such as the 6BTV is electrically 1/4 wave long at the various operating frequencies. That eliminates having to deal with reactance at the feedpoint, but the resistive part of the feed impedance is so low that ground loss becomes a major issue. The losses in the many traps is another issue, and not all of the antenna is radiating on most bands.

The 43 foot vertical, OTOH, is mechanically and electrically quite simple. Its main problem is the varied and complex feedpoint impedance, which IMHO is best dealt with by a matching network at the feedpoint.

I don't know how much a 6BTV costs, but I suspect that a ham with a bit of ingenuity could homebrew a 43 foot vertical and matching network for a lot less money.

73 de Jim, N2EY
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on March 28, 2009 Mail this to a friend!
"What if the twin lead ran with its surface perpendicular to the metal surface with one side closer to the metal than the other conductor?"

Then the physical symmetry is broken ;-)

 
RE: The 43' Vertical -- a Theoretical Analysis  
by HFRF on March 28, 2009 Mail this to a friend!
I thought we were talking about the symmetry between the 2 conductors of a transmission line that supposedly determines whether a transmission line is working as a balanced or unbalanced line (as determined by source and load currents in and out of a line).

As far as N3OX's statement that twin lead would behave as unbalanced line when perpendicular to the surface of a metal plate? Really? The difference in distance between conductors to a metal plate when a piece of twin lead is normal to the surface of a plate at 3.5 MHz is about .00032 wavelength. Do you really think that makes a difference?

I'm done with this topic, have fun all.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by LU1YNE on March 28, 2009 Mail this to a friend!
I think this is a very nice THEORETICAL analysis. HFRF is talking no-sense.
He hasn't even read the title of the article properly! He doesn't post his call. All of his WHAT-IFs are based in breaking the electric or physical symmetry! N2EY says "By definition, TRUE physical symmetry causes electrical symmetry", not vice versa. And TRUE should also be read as IDEAL, meaning no disturbances like HFRF states.

In short I think his comment -for all above stated- is easily disregardable.




73 es gud DX
Ed, LU1YNE
Patagonia
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on March 28, 2009 Mail this to a friend!
"I suspect that a ham with a bit of ingenuity could homebrew a 43 foot vertical and matching network for a lot less money.
"

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

and for full-on "all band" coverage (though I'd use a seperate good loading coil for 80m)

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

I also tried a coil for 160m but honestly, even with a coil it sucked. Painfully narrow bandwidth, detuned if you sneezed on it, and yeah, I could make some contacts, but I had a really hard time raising EU stations.

There are also issues with power handling. You manage to feed a 43 foot whip efficiently on 160m, you get a very high voltage across the coil. You get a very intense electric field around it. Someone related an anecdote to me about doing something similar over a great ground radial system with a great coil and starting a grass fire.

Cost and complexity and construction time for homebrew matching networks escalate significantly if you want to do many bands, not just a couple. Autotuners, even at the 100W level, all of a sudden price the cheapest homebrew 43 footer out of range of a 6BTV or something.

Then, there are some bands that just aren't bad in a given installation. Is it really worth adding a matching network to erase the 1.3dB direct feed losses on 40m for RG-213 in the tables above?

A good approach might be to calculate the actual line losses in your own actual installation and just "fix" those bands that were broken. But I think that's more work than a lot of hams want to do, especially if they don't think there's a problem at all.

I took my current sixty foot vertical, nearly a half wavelength on 40m, with an insane impedance for direct coax feed and fed it directly to compare with my good matching network:

http://n3ox.net/projects/sixtyvert/fortynet_lg.jpg

I've got a mixture of RG-8/X and RG-213 back to the shack, maybe only about 40-50 feet worth, about half and half.

I switched back and forth, testing the difference between direct coax feed to the bare element matched with an indoor tuner and the proper matching network, and I saw about 10dB difference on strong broadcast stations.

Then I went down to the CW portion and busted a pileup on C57R, running about 10W effective radiated power.

I personally think throwing 10dB out the window means the antenna system sucks. Someone else would have only considered the fact that they "busted a pileup on a C5 with 100W" I also worked ZC4VJ (a little hard) had a nice quick chat with I1YRL (big sig) who didn't even seem to notice that I was +3dBqrp... got a 579 and he clearly had solid copy.

I knew I was using a poor antenna system. If I didn't know it, I might have thought it was a good one. And that's with worse loss than would be typical in a lot of installations for the 43 footer system on the bands above 80m.

I believe in the value of a few dB, but a lot of people don't even notice it's missing. I've decided to accept that and let people waste their money while thinking they have a really killer antenna.

The thing that worries me is that someone would throw away 6dB in the feedline and buy a "500W" amplifier from RM Italy when the boys on 75m tell 'em they're weak ;-)

73
Dan












 
The 43' Vertical -- a Theoretical Analysis  
by WR9H on March 28, 2009 Mail this to a friend!
While I'm sensitive to the need for theoretical antenna analysis, I wonder if we are not starting to relie on it too much. There are MANY amateurs using theoretically iffy antennas that are making QSOs.

Example: I have experimented with an Isotron 40. First I was told that the feedline radiates. I took the antenna down, set it up on my drive way on a PVC mast and used a two foot long RG-58 feedline. It still worked. Was the radiation off the two foot feedline? I shortened it to 3 inches!! Same signal report across town and 600 miles away. Was the signal radiating off the feedline? DOES IT MATTER??

Come on antenna gurus put some of these antennas up and actually run some RF into them.

Yours in Radio,
WR9H
Herb
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on March 28, 2009 Mail this to a friend!
"The difference in distance between conductors to a metal plate when a piece of twin lead is normal to the surface of a plate at 3.5 MHz is about .00032 wavelength."

If the twinlead is 0.1 wavelength from the plate, that's about 0.3% difference, and I'd agree nothing much of consequence happens.

If the center of the twinlead is 0.00065 wavelengths from the plate the story is a little different.

If you're willing to be pedantic enough to have been talking about the situation in which the line is hundreds of line spacings away from the plate, then you're right about the physical symmetry not being importantly broken. Kind of a hollow victory though.


"
As far as N3OX's statement that twin lead would behave as unbalanced line when perpendicular to the surface of a metal plate?"

I didn't say it would behave as an unbalanced line. I said the physical symmetry for differential mode currents is broken, which is absolutely true if one conductor is 3 milliwavelengths from the plate and the other is 6 milliwavelengths from the plate.

Twin lead is only unbalanced when the common mode current is nonzero, so I wouldn't claim that any line was unbalanced without knowing what was hanging off each end.

But physical symmetry is not irrelevant to the question of balance in ham stations. The number of baluns you need and where you put them depends a lot on the physical symmetry of the installation.


73
Dan





 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on March 28, 2009 Mail this to a friend!
"DOES IT MATTER??"

Herb, here's my opinion.

If you are going to put up an antenna and make contacts at your home station, it doesn't matter one darn bit if there's any theoretical or experimental evidence that it's a decent antenna.

You can run whatever you want if it makes you happy in your day to day ham activities.

The problem comes when someone starts recommending antennas to other hams and telling them they are "good" or "bad" antennas without any dB values to back that up.

I think that hams searching for new antenna ideas should be able to make decisions based on numbers related to the actual efficiency, gain, directivity and bandwidth of antennas.

Otherwise, antenna choice becomes a pure popularity contest.

Imagine what would happen if every single ham used an antenna that had 20dB of loss with respect to a dipole 1/4 wavelength off the ground. Every single full legal limit station would sound like they were running 15W. How fun would ham radio be for the little guys if everyone was a little guy?

If we stop understanding antennas, stop assessing them on the basis of calculated and measured properties scientifically compared with other antenna designs, then everyone ends up with a piss-poor signal in the end.

So, I don't expect to convince anyone in particular that they should strive for some particular level of efficiency in their own home station, but I will always keep telling people if there's some way they could make their antenna system better, because in the end, it matters to the fun of ham radio for at least some people to run good antenna systems.

73
Dan










 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on March 28, 2009 Mail this to a friend!
"Come on antenna gurus put some of these antennas up and actually run some RF into them. "

A lot of people who do a lot of modeling and write a lot of articles also build a LOT of antennas.

But I think it takes about 10 times the work to make a point with a well documented experimental effort than it does to write an article based on antenna modeling.

And in the case of articles related to inefficient antennas, some of the gurus would be spending their time building, very carefully testing, photographing, and writing about antennas that weren't in the LEAST bit useful to them.

If I had spent a week's worth of my ham radio time, I could have taken reasonable field strength measurements directly comparing my 40 foot wire vertical with matching network to my 40 foot wire vertical with indoor tuner and UNUN and with another day or two I could have written it up on eHam.

But you know what would happen? Someone would come in and say "yeah, but it's not a ZERO FIVE or a DX ENGINEERING antenna. It doesn't have an ARRAY SOLUTIONS or BALUN DESIGNS UNUN"

So what's the point? You want to build a somewhat better 43 footer, I've got some starting point matching networks on my website. You don't want that? Fine. But not everyone who writes modeling articles is off in lala land avoiding putting RF to wire. Some people, myself included, just find it a lot
easier to write an article based around a modeling program where it's easy to generate pictures and sufficient amounts of data to be convincing.

Purely experimental articles on antennas are either *very* difficult to write or practically useless, because you have to really document your technique to show that you've got a right answer. You need to get +/- 1dB error bars to convince even a ham audience that you measured 3dB losses.

10dB is easier, but it still takes a lot of setup, and consideration of confounding factors.

You can't even measure radiation efficiency directly without a helicopter. You need to make at least some assumptions about the antenna pattern.

The prospect of writing good experimental articles gets a little daunting if you want to make a convincing, relatively airtight argument about something by experimental means.

Maybe 30 years down the road I'll have some more time to do that.

73
Dan
 
RE: The 43' Vertical -- a Theoretical Analysis  
by W9PMZ on March 28, 2009 Mail this to a friend!
This isn't theory, but just on the air obervations.

I have a DX Engineering 43' chunk of aluminum and I also have a Hustler 5BTV. Ground consists of 70 33' radials.

Using a Kenwood TS-850SAT a AL-572 a MFJ-989D I was able to bust pile-ups on 40M and 80M to Europe on the 43' and so-so on the Hustler. However this was not an true A/B comparison (can only have one antenna at a time).

It works. But once global warming starts anew with the next roound of sun spots I may take the 43' antenna down for an antenna that favors this higher bands.

73,

Carl - W9PMZ
 
RE: The 43' Vertical -- a Theoretical Analysis  
by WX7G on March 28, 2009 Mail this to a friend!
Thank you to all for your valuable feedback.

I have 'closed the loop' between simulation and field measurements on many antennas. These results are published at AntenneX and EDN. Subjects include the Isotron, Phased-field (PF), Tak-tenna, small dipoles, small monopoles, as well as other antennas. Other authors have tackled the CFA and the EH.

Dont' fear simulations. This is how things are done in the world of engineering. For example, the ICs in your transceiver were designed in simulation. At work (EMC, SI, and analog design) I design circuits and systems in simulation with the goal of meeting EMC, SI, and other specs. We end up closing the loop thru actual measurements that are then used to refine the models.

The two main points of this article, line loss and radiation pattern, are such that field measurements would merely confirm the simulations.

Numbers are provided so that the ham chosing between the 43' vertical and an alternative can make an informed decision. He can then 'design' his particular 43' vertical installation so as maximize performance within the contraints of time, budget, and space.

When using ladder line into a grounded monopole we have a complex situation. Fed against GND at the far end of the ladder line we have a three-wire line. Ladder line "hot", ladder line "cold" and GND. When fed at the far end thru an ideal balun (having infinite common-mode impedance) we have the simulation that was performed. The purpose of this simulation is not to accurately quanify things but to show that the antenna can perform this way - that things don't fall completely apart.

An analysis of a 4:1 current unun is a subject for a future article. For modeling ununs/baluns I use SPICE. A "behavioral" model derived from this is then placed into NEC and run. I have the equipment to perform actual measurements. This has been on my list of things to do for a few years. I have not decided where to send this article; eham, at AntenneX, or elsewhere.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by W7ETA on March 28, 2009 Mail this to a friend!
Great Prose.

All in all, a well thought out, well presented, nice tight article.

Great job OM.

best from Tucson
Bob
 
RE: The 43' Vertical -- a Theoretical Analysis  
by WX7G on March 28, 2009 Mail this to a friend!
It would be great if amateur baluns were specified as to common-mode impedance, maximum CM current, power dissipation, loss, frequency response, and so on.

When I search for an off-the-shelf common-mode inductor (a 'balun') for use at work the device is specified as to CM impedance and DC resistance. The SRF, differential-mode impedance, Q, and other parameters are often supplied. When designing a custom CM inductor I design to these parameters.

But look to purchase an amateur balun, such as a "W8JI Designed" balun at DX Engineering, and it is a 'black box' with no useful specs. What is the CM impedance? What is the loss for various I/O impedances? Will my 43' vertical work better with it or without it? It is rated for X kW. Is this for the matched case? What happens in the real world?

And if these numbers were supplied would the majority of interested hams know how to interpret them? Would these specs start a 'spec war' that would drive balun design to higher numbers without regard to the trade-offs involved? Some investigation and learning are in order.

In my article one can see the line loss numbers between direct coax feed and ideal 4:1 unun feed. One is left to wonder if the advantage offered by the balun improved line loss is offset by balun loss (unknown) and possibly lower tuner loss (unknown). As stated, these two parameters I have no have data for. Each can be accurately simulated and/or measured for specific ununs/baluns and tuners.

A conversation has been started. Some basic parameters have been looked at - line loss and radiation patterns. These numbers take out some of the subjective nature of the often heard comments that line loss is unbareable or that all of the radiation goes up at useless angles. We now have numbers for these two subjects.

We can now move onto the balun. Later we can look at the open wire situation, which is more of an aside as it is not a popular feed method.

By the way, the ladder line simulation was performed with open-wire line spaced 2" placed 12" above 'real' GND. As such the ladder line E and H fields are rather weak at GND. Therefore the additional line loss is rather small. How small? Analysis, calculations, or measure can tell us. Based on rough paper-and-pencil calculations is it less than 1 dB additional in a 75' run. Not enough to universally condemn ladder line. Compared to the price-equivalent, RG-58, which would you chose?

I will write up an analysis of 4:1 baluns/ununs. I will restrict this to an analysis of these devices in general with one test vehicle. Detailed design methods will be saved for another time.

The actual test vehicle will be an "W8JI Designed" balun from DX Engineering.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by K5END on March 28, 2009 Mail this to a friend!

quote, "Intuitive judgments are almost always wrong."



I have a hunch that statement is correct.

But wouldn't such an intuitive judgment mean the statement is likely to be incorrect?

:-)
 
RE: The 43' Vertical -- a Theoretical Analysis  
by W4WLC on March 28, 2009 Mail this to a friend!
I have a 43 foot vertical up with 80 - 25 foot radials. I live in Florida and the soil is very sandy. I have a 4:1 balun at the feed pint and about 100 ft of low loss RG-8 to the shack. Using a Palstar ZM-30 all the ham bands fromm 160 - 10 are 2.1 or below except for 60 meters which is in 3.5 range. Maybe I don't have enough radials down or I need longer ones. It isn't a beam but it works...

Dave
W4WLC
 
RE: The 43' Vertical -- a Theoretical Analysis  
by WX7G on March 28, 2009 Mail this to a friend!
Your observation about intuitive judgements might be largely correct. Intuition can be the beginning of an engineering analysis. It can also serve as a reality check of the results. But to rely on intuition or empiricism to arrive at an engineering solution went out of style sometime before 1900.

So many questions posited on eham are not understood by the respondents. The answer given often has little to do with the question.

A simple question such as "what is 2 plus 2" can begin a thread that quickly mutates while never answering the original question. Give it a try.

Communications between the parties is sometimes twisted. A combination of the philosophy of science and the philosophy of language is a useful tool for analyzing what is occuring. It can be fascinating.

 
RE: The 43' Vertical -- a Theoretical Analysis  
by KA3NXN on March 28, 2009 Mail this to a friend!
I have another mod for this antenna that is supposed to make it really sing on 160-40. From the mod I got you take an insulated 14 GA stranded 60' piece of wire. The wire is stripped right in the middle and this is clamped to the vertical radiator about 15' from the base of the antenna, Then the ends of the wire are strung out in a "V" formation from the center radiator in an upward direction. Securing the ends of the wire to the trees. This is supposed to give fantastic 160-40 meter performance at the cost of the performance of all the higher bands,

Thank you for the analysis. I have my Zero-Five antenna ground mounted on a hill in my back yard with a home made radial plate and I am using about 60, 65' insulated radials. I am able to tune all bands from 160-6 meter with just a simple LDG Z-100 tuner. El Cheapo! Thank you for a very informative article, I'll put your theory to the test,

Jaime-KA3NXN
 
RE: The 43' Vertical -- a Theoretical Analysis  
by K5END on March 28, 2009 Mail this to a friend!

PK, sure. I'll try it.

Question: What is 2 + 2?


Typical internet forum answer 1: Be sure to take into account the number of significant digits, because the answer could be 1.99348 or 2.00912.

Typical internet forum 2: It depends on whether the values are assumed to be in linear, Euclidean dimensions. You have to be careful to avoid overlooking possible relativistic effects. Also be sure to take the eigenvalues into account and use your normalized matrix.

Typical internet forum answer 3: The answer is 5.

Typical response to internet forum answer 3: No it's not, you stupid moron. The answer is 7, and no amount of reason will convince me otherwise.

Typical internet forum answer 4: I have no education in math whatsoever, but I claim to be an expert on addition, having written several articles published on the internet, plus I have my own website (which automatically makes me an expert) and can tell you without doubt the answer is 17.

Answer 5: I am a new no-code extra, but I have a PhD in physics and did my dissertation on Orthogonal Frequency Division Multiplexing, using Fourier spectral analysis and J2 Bessel functions to prove compliance with the FCC bandwidth efficiency in digital transmission, the application of which is now used widely in digital data transmission. I teach at M.I.T. and serve on the board of several state-of-the-art technological corporations in the Fortune 100, plus I serve as an advisor to the NSA in code breaking, and can tell you: 2 + 2 = 4.

Typical response to answer 5: You no-code-extra wonder boys don't know what you are talking about. Why the heck did they eliminate the code requirement anyway? See how these idiot know-it-alls NEWBIES are? Sure, the answer is 4, but he got lucky and guessed it. He doesn't know anything about Ham radio.





 
RE: The 43' Vertical -- a Theoretical Analysis  
by ZENKI on March 28, 2009 Mail this to a friend!
I would just add a trap on the top and make this 43 foot vertical into a dual band 80/160 meter vertical with a top hat.

Anyone make decent 5kw rated traps?

I also would simply add another wire supported by insulators to the main radiator and feed this separately for the higher bands. With this configuration at least i would get a decent angle of radiation on all bands.

These new untuned verticals are fast becoming the G5RV's of the vertical world.

I hate to raise the issue of fan dipoles,,,,, but if i had a 43 support I would use a fan dipole on the higher bands and get 5db of ground gain, it sure would kill any super long multiband vertical... Different strokes for different folks.



 
RE: The 43' Vertical -- a Theoretical Analysis  
by K5END on March 28, 2009 Mail this to a friend!
By the way, Dave.

Your article was presented very nicely.

You started by defining the scope and purpose of the article, you went through it logically and performed the analysis with models.

You finished up with a concise conclusion and offered your qualitative opinion.

We need more articles like this one.

LK



 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on March 28, 2009 Mail this to a friend!
"if i had a 43 support I would use a fan dipole on the higher bands and get 5db of ground gain, it sure would kill any super long multiband vertical"

Man, you must be made of money.

$360 for the 43 foot support alone. That's $8.37 per foot of conductive stuff.

You put a 40/30/20/17 Fan Dipole on top of that sucker, that's like another 180 feet of conductor. Now we're up above $1800 for the parallel dipole and support.

Then you have to spend all that time trimming and tuning the antenna.

Not for me, man.

I'm going to stick with my flamethrower. It's an actual flamethrower. I use it to scare guys with beams out of the shack so I can commandeer their station to make some contacts.

73
Dan






 
RE: The 43' Vertical -- a Theoretical Analysis  
by K6JPA on March 28, 2009 Mail this to a friend!
LK, you have me rolling from laughter with that one...
 
RE: The 43' Vertical -- a Theoretical Analysis  
by K6JPA on March 28, 2009 Mail this to a friend!
... That, of course, referring to the five answer types ...
 
RE: The 43' Vertical -- a Theoretical Analysis  
by K5END on March 28, 2009 Mail this to a friend!
Thanks, Jim

It was almost copy and paste.

Almost.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by W7ETA on March 29, 2009 Mail this to a friend!
2+2=?

Well, in theory, it depends upon the base.

 
RE: The 43' Vertical -- a Theoretical Analysis  
by K5END on March 29, 2009 Mail this to a friend!
Hexadecimal.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by K5END on March 29, 2009 Mail this to a friend!
ETA

Ya know, in base 10 and 16 the answer is still 4 and it's not a valid question in binary, but I like the way you think.

Good one.
73



 
RE: The 43' Vertical -- a Theoretical Analysis  
by W6RMK on March 29, 2009 Mail this to a friend!
"
I don't know how much a 6BTV costs, but I suspect that a ham with a bit of ingenuity could homebrew a 43 foot vertical and matching network for a lot less money.
"

About $150 or so, 3 or 4 years ago...

But comparing against homebrew isn't a fair comparison.

What you should compare against is a 43 ft vertical and an autotuner at the base,since the 6BTV basically provides a decent match at the feedpoint for all the relevant bands without user interaction. That combination is probably in the $500 range.

That said... modeling things close to the ground with NEC2/MiniNEC is probably not the best plan.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by AA4PB on March 29, 2009 Mail this to a friend!
The problem with "practical observation" vs "theoretical analysis" is that most hams don't have the facilities to make technically accurate "practical observations". Most times its a matter of I put up the antenna and make some contacts with it so it must work great. Not even any A/B comparison against a reference antenna under the same signals and same band conditions.

Theoretical analysis at least lets you know what you are dealing with and might expect in the way of performance. Absolutely nothing wrong with 3-6dB of feed system loss if you know its there and are willing to accept that in trade for something else. The problem comes when you accept it without knowing it is there and then unknowingly recommend the system to others when they might have other more effective options available.

The biggest problem is the manufacturers who basically sell a single band antenna as an all-band antenna claiming that all you have to do is add a tuner with sufficient range - and if your tuner won't make it then add some more loss in the feed system. I've seen 80M dipoles advertised as "all-band" (the fine print says a tuner must be used). I'm sure it would be helpful to the newer guys if the manufactures would at least provide an honest explanation of how their antenna works.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by KI8DJ on March 29, 2009 Mail this to a friend!
Actually an 80 meter dipole does make a pretty good all band antenna if the feedline is low loss and not too long. Height above ground and propagation are big factors of course
 
RE: The 43' Vertical -- a Theoretical Analysis  
by WX7G on March 29, 2009 Mail this to a friend!
AA4PB, I agree with you. The manufacturers do leave us in the dark. How much loss does their tuner incur with various loads? How much loss does a 43' vertical with the 150' of RG-213 incur? The B&W wideband terminated dipole spec sheet doesn't mention the efficiency of 25% on the high bands and a couple of percent on the low bands. How about that expensive balun? How does it perform into real world loads? So we are left to guess.

As you say, few hams run an A-B comparison. They think that because they get some good signal reports everything is fine. Given the same power at both ends of the RF link the signal strength at both ends will be the same. Run 100 watts and call an S-8 station running 100 watts. You will receive an S-8 report right back.

Some of the attraction of the 43' vertical is that one can 'pimp their antenna.' They can put in lots of radials, connect a fine unun, install expensive coax. They feel good about it, the antenna makes plenty of contacts, the manufacturers sell some stuff, and everybody is happy.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N2EY on March 29, 2009 Mail this to a friend!
W6RMK writes: "But comparing against homebrew isn't a fair comparison.

What you should compare against is a 43 ft vertical and an autotuner at the base,since the 6BTV basically provides a decent match at the feedpoint for all the relevant bands without user interaction. That combination is probably in the $500 range."

I disagree, sort of.

IMHO, homebrewing a 6BTV is much more complex project than homebrewing a 43 foot vertical and tuner. (Of course that depends on the contents of the junkbox, the mechanical capability of the ham and a bunch of other factors.)

From what I see, comparative performance depends a lot on a whole bunch of factors. For example, above 20 MHz the 6BTV with a couple of radials is probably not much different than the 43 footer with base network, and may even be better. On 40 meters there may be a very big difference.

With a simple L network at the base of the 43 footer, one can almost certainly get a very low SWR from bandedge to bandedge on 40, while the 6BTV will probably need the use of a tuner in the shack to cover 7.0 to 7.3

Etc. All sorts of variables come into play.

W6RMK: "That said... modeling things close to the ground with NEC2/MiniNEC is probably not the best plan."

Why? Is there a better option?

Granted, most modeling software requires that one make some assumptions about ground losses.

73 de Jim, N2EY
 
RE: The 43' Vertical -- a Theoretical Analysis  
by WX7G on March 29, 2009 Mail this to a friend!
Jim,

you are right about having no other choices than NEC. NEC-4 will give the most realistic results and is considered good for ground mounted verticals and buried radials. I haven't got that, I have NEC-2. Even at work I ordered NEC-2 because the work we do does not involve anything but perfect GND. So, no real advantage to using NEC-4.

Using NEC-2 the method to account for GND losses in the near field is to place four radials a couple inches above GND and add series loss resistance to the radiator, at the base. 20 ohms will get the results close for the 'average' installation.

When we are comparing similar antennas the inaccuracies of NEC-2 become less important.

In the case of the 43' vertical the resistive portion of the base impedance is a high 90 ohms or more on 40-10 meters. This makes for relatively low ground loss even with a just a few radials. This has to be considered an advantage of the 43' vertical over the 1/4 wavelength vertical (36 ohm base R) and the 4BTV (20-25 ohms radiation resistance). Place an autotuner at the base and the 43' vertical beats a 1/4 wavelength vertical, if both have a marginal ground system.

The DX Engineering recommendation of 150' of RG-213 coax makes for a nice impedance for the shack located tuner, but watch that line loss, especially on 80 meters.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by AA4PB on March 29, 2009 Mail this to a friend!
Actually an 80 meter dipole does make a pretty good all band antenna if the feedline is low loss and not too long.
------------------------------------------------------
Sure it does if you have an appropriate tuner. By itself (as sold) it is NOT an all-band antenna however. Try it on all bands with 100-feet of RG58 or using the built-in tuner in the transceiver.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by NA0AA on March 29, 2009 Mail this to a friend!
Interesting information.

I've been considering one of these for a QTH I have access to but am unable to install anything more than this [no tall trees, no way to install towers]. I'm thinking that an SGC type antenna coupler at the base would be the way to go since your radio would see 2:1 or less for low feedline losses. With no traps or anything to adjust it's got to be a winner for pure simplicity.

I suspect that if one wanted to add a capacity hat it would really improve 80 and 160 meter operation, I have no idea what that would do to the higher bands though. I suppose if you really were slick you could make a cap hat with a relay on the top of the antenna to disconnect it.

Sure, someday real world testing would be nice, but this information helps with some decision making.

Thanks for the article.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by QRZDXR2 on March 29, 2009 Mail this to a friend!
I too would like to know the insertion loss's vs the actual radiation of the antenna with such a high SWR.


While the antenna balancing, turner, is used to match the antenna the SWR on the line does not go away. Thus the hiher SWR the greater the losses within the coax or feeds...

While 43, 66 ft ( 23 ft highter) is a nice length for a antenna, I think I would rather use the 33 or 66 ft length. Then the SWR would be lower, the field greater and the losses much much less.

Here then you approch the same charts as the hygain ht (high tower) antenna of old. The hygain 18ht antenna then has better fields due to stubbing for the bands.

The 43 ft vertical offers some interesting thoughts and appears as though you did a lot of work... thanks for the info...

 
RE: The 43' Vertical -- a Theoretical Analysis  
by WX7G on March 30, 2009 Mail this to a friend!
KG6WOU, you are right to consider a top hat. I did this with a 33' vertical and a 43' vertical (yes I did build one seven years ago). This first article was to get started and so no improvements were discussed.

No relay is needed to switch bands. Very simple and very effective. Here is the easy way to put the antenna on 160 meters. Go to DX Engineerng and order a Hustler RM-80 resonator. Order the HotRodz top hat hub and six 4' spokes. Mount this at the top and tune it up. A BW of 20 kHz on top band is to be had.

It can be improved with a bigger top hat and a homebrewed coil. For plans see AntenneX several years ago. Search under "The Big 160 Meter..."
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N2EY on March 30, 2009 Mail this to a friend!
WX7G writes: "In the case of the 43' vertical the resistive portion of the base impedance is a high 90 ohms or more on 40-10 meters. This makes for relatively low ground loss even with a just a few radials. This has to be considered an advantage of the 43' vertical over the 1/4 wavelength vertical (36 ohm base R) and the 4BTV (20-25 ohms radiation resistance). Place an autotuner at the base and the 43' vertical beats a 1/4 wavelength vertical, if both have a marginal ground system."

Agreed.

But I think there's more to it than that.

I used G4FGQ's ENDFEED to get an idea of the feedpoint impedance of a ~43 foot vertical, and the L network needed to match it to 50 ohms. (Granted, I don't know exactly how accurate all the assumptions are).

What I found was that on all bands from 40 through 10, the impedance could be matched by a simple L network with a series coil of 1 to 4 uH and a parallel cap of 20 to 350 pf. (No more than 100 pf was needed on any band except 40, so a 100 pf variable plus a fixed cap could do the job). Also, the feedpoint Z appears to be low enough that the high voltages associated with an end-fed half-wave don't become a problem, yet, as you say, high enough that ground losses are reasonable.

80/75 is another story; it needed a two-inductor L network, and losses in the ground network become very important. But that's true of any 'short' vertical.

I think the "magic" of the ~43 foot length is that it's relatively easy to match on several bands, compared to resonant lengths.

My main interest in this antenna is for Field Day, to give one of the stations a choice of dipole or vertical. If the site has a tree that can provide a single high support, a wire version could serve for 40, 20 and 15 with a simple L network at the feedpoint.

73 de Jim, N2EY

 
RE: The 43' Vertical -- a Theoretical Analysis  
by KT4WO on March 30, 2009 Mail this to a friend!
I feed a ground rod with LDG Z-100 tuner and the SWR is 1:1 .. If I can hear'em - I can work'em.




Sure wish I could hear someone :)

Tnx for the nice write.

KT4WO

 
RE: The 43' Vertical -- a Theoretical Analysis  
by WA1RNE on March 30, 2009 Mail this to a friend!

"I think the "magic" of the ~43 foot length is that it's relatively easy to match on several bands, compared to resonant lengths."

"My main interest in this antenna is for Field Day, to give one of the stations a choice of dipole or vertical. If the site has a tree that can provide a single high support, a wire version could serve for 40, 20 and 15 with a simple L network at the feedpoint."


>>> Jim, it may be easier to match - but for which tuner? Manufacturers like DX Engineering are recommending the addition of 150'+ of RG-213 to bring the feedpoint impedance into a range that some tuners can handle more easily. As you know, with the varitations in feedpoint impedance and very high SWR on some bands, the feedline is going to take a beating at 1500 watts and will likely fail.


For Field Day it might be worth a try, but I would make that support 50' or better and elevate the feedpoint 7' or more, along with >= 4 radials per band and a tuner. That would be a fun project for a Field Day group.


The article is very good but it didn't cover 2 very important aspects of this antenna:

1) Antenna tuner power handling over 100 watts on 40-10 meters and the challenges faced in feeding this antenna on 160 and 80 meters at even 100 watts.

2) Total System Cost


*** I realize the author is presenting an analysis of the antenna's characteristics and performance, but in doing so he also states part of the purpose is "to obtain quantitative data that you can use to make decisions about this antenna."

- One of those decisions must be whether you can feed RF power efficiently into this antenna with a convenient means.

- Another should be overall value and cost.



> Tuners and High Power

Most of the confusion surrounding the use of this antenna has been centered squarely on how to couple the feedline to the antenna.

The most convenient way to feed power into it is to use a 4:1 unun, 50 ohm line and a tuner in the shack. The author has done a good job showing the trade-offs in efficiency using this feed method and ladder line feed. Some of the antenna manufacturers advise that a tuner should be connected at the feedpoint for best efficiency - no big secret there.

However, the power handling limitations of available tuners has not been covered, and excluding homebrew tuners, this can be a real problem for users of this antenna - especially if you intend to use an autotuner.



> Comparison of total system cost versus other comparable verticals.


I posted the total system costs for the cheapest version of the DX Engineering 43' footer on a recent Elmer's post.

The antenna is $299.50.

Add a tuner, 4:1 unun and radials and the cost jumps to between $800 and $1600 depending on the tuner and whether you need to add extra feedline to make the tuner "happy".

These extras are not in the realm of mere accessories, adding 10-15% onto the bill. After you're done, we're talking 2.7-5x the cost of the original antenna.


At the end of the day, you have an antenna that is advertised by all the commercial manufacturers as a 160-10 meter antenna that won't operate efficiently on most bands without a good tuner, can't (IMO) be run conveniently and efficiently with over 100 watts without a *very expensive* remote tuner and the total system cost will run you as much as a large multiband yagi.

There are other alternatives available that - IMO - do a better job satisfying these 2 important requirements - and for less money.


...WA1RNE
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on March 30, 2009 Mail this to a friend!
"At the end of the day, you have an antenna that is advertised by all the commercial manufacturers as a 160-10 meter antenna that won't operate efficiently on most bands without a good tuner, can't (IMO) be run conveniently and efficiently with over 100 watts without a *very expensive* remote tuner and the total system cost will run you as much as a large multiband yagi."

But ... but ... it's so tall... and shiny.

:(

The funny thing about 80m operation, at least, is that it's fairly straightforward to drop enough power in the feedline and likely in the UNUN to erase the benefit of running more than 100W in the first place.

So the guy who runs to Home Depot for PVC pipe and wire to build his own loading and shunt matching coil to run 100W might beat the guy running 600W or 800W to the "more convenient" configuration. 'Course on 80m it's pretty easy to build a high power matching network. It's tough to roll your own HV capacitors, but building a couple coils that will take a bunch of current and stand off a couple kV at 3.5MHz is a snap. Just need a 20ft box of 1/4" refrigeration tubing or something else stiff and copper that will hold its shape more or less.

I'm actually a little surprised that someone isn't selling a 43-footer-specific tuner. It's probably a serious business opportunity for someone that wants to jump on the bandwagon. A high power AUTOTUNER is tough. A set-and-forget semi-auto with just enough matching range to cover the slight variations in design isn't so difficult, I would guess.

73
Dan



 
RE: The 43' Vertical -- a Theoretical Analysis  
by AB7E on March 30, 2009 Mail this to a friend!

I sure wish the "if I can hear 'em on a crummy antenna I can work 'em on a crummy antenna" criteria for rating the effectiveness of antennas would go away. Yes ... I know that S/N is more important for receive than power transfer efficiency, but this is still a really silly and subjective way to judge an antenna.

Dave AB7E
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on March 31, 2009 Mail this to a friend!
"this is still a really silly and subjective way to judge an antenna.
"

But if you add to it "I'm happy with what I hear," then it becomes a very straightforward, common sense way to judge an "antenna."

I want "I can work 'em if I hear 'em" to stop being a reason to recommend an antenna to others too, but I think we need to understand where it comes from:

No antenna = no ham radio
Any antenna = worldwide contacts in some quantity

Doesn't matter how bad it is, the moment you plug one in, you're on the air and the moment you unplug it you're off, because there are few objects sold as antennas that are likely to do worse than -20dBi and very few if any that do worse than -30dBi. The incidental radiation off your accessory cables and the fringing field out of your SO-239 is probably 30dB worse than the worst antenna you can buy or build that isn't intentionally shielded.

I am not laissez-faire about the problem. Ham radio is a two way hobby and I think it's reasonable to encourage people who have a choice in the matter to run good antennas instead of mediocre or really bad ones.

But if you think about it, it's *not at all* "silly" to note that a given radio station system fills your log with nice contacts when the crappy antenna is plugged in and stops doing so when you don't use it.

I think we need to focus on showing people why even a crummy antenna will generally lead to fun instead of frustration for a lot of hams, but that doesn't mean a better antenna isn't better.

I've seen, for good reason, a lot of resistance from people who have been told on these forums that the contacts they made are a "meaningless" measure of their antenna effectiveness. While it might be technically true in the sense that making a contact means an antenna is within +/- 30dB of a good antenna, we can't forget that it is a very straightforward assessment of whether or not they're happy with their own station.

Letting people know they shouldn't attribute too much success to the *antenna* in particular is important overall, but temper it with the realization that the old saw of "any antenna is better than no antenna" may actually be a pretty profound statement if you measure it quantitatively on average ;-)

Putting a leak in the shield of your radio and getting it to generate full power is probably the gain equivalent to replacing the Isotron that did that with a world-class contest station.

The extreme dynamic range of HF signals taken with the comparatively narrow spread of HF antenna system gains does upset common-sense reckoning of how any single antenna with no comparison is working, but tread softly when you work on getting this across to people, because if you're not careful then things that go against common sense intuition are seen as the failure of theory in the face of real-world results.

Too many people out there have been confronted by a bold know-it-all who told them their Isotron wouldn't work the day after they made DXCC with it.

That causes lasting damage to our cause ;-)

73
Dan








 
The 43' Vertical -- a Theoretical Analysis  
by WA3SKN on March 31, 2009 Mail this to a friend!
Dave... Good article!
I doubt that you will convince either side of the "Pro-43 ft" vs the "Anti-43 ft" debate crowd though. It's still "feuding" territory.
73s.

-Mike.
 
The 43' Vertical -- a Theoretical Analysis  
by N6BIZ on March 31, 2009 Mail this to a friend!
I USED A 43 FT VERTCAL WITH 12 17 FT ABOVE GROUND RADIALS 7 FT UP I FEED IT WITH COAX,AND LADDER LINE ON 80 20 MTRS NOW ON 40 MTRS I FED THIS THING WITH COAX SHE WAS A PILE UP BUSTER I HAD A BLAST WITH IT USING NO POWER THEN I'D KICK IN A HENRY 2K THIS WAS THE BEST ALL AROUND ANTENNA I EVER USED IN MY 40 + YEARS IN HAM RADIO HAD A BEAM TOO AND MOST OF THE TIME THE VERTICAL WOULD OUT PERFORM THE BEAM UP 40 FT IF YOU ARE INTO DX THIS ANTENNA IS THE WAY TO GO... WHAT AN ANTENNA YOU WILL LOVE IT I MISS IT THEN I HAD TO MOVE LOL
73 GARY
 
RE: The 43' Vertical -- a Theoretical Analysis  
by W7ETA on March 31, 2009 Mail this to a friend!
Hypothesis: 2+2=4
Null: 2+2 does not =4
Two tail test: 2+2>4; 2+2<4
Data set shows that under some circumstances, 2+2 > 4
Therefor, accept the null hypothesis.
Reject models of 2+2=4
 
RE: The 43' Vertical -- a Theoretical Analysis  
by AB7E on March 31, 2009 Mail this to a friend!
N3OX: "I think we need to focus on showing people why even a crummy antenna will generally lead to fun instead of frustration for a lot of hams, but that doesn't mean a better antenna isn't better."

I think that's basically my point. Many times the "I can work 'em if I can hear 'em" comment is used as a justification for settling for a poor choice in antennas, or for spending $300 on something that's 15 db down from a piece of wire. I'd have no problem at all if the user was simply happy to make a few contacts and realized what a sub-optimum antenna they were using for their particular situation, but that is not usually the case. More often it is in the context of recommending that antenna to others who probably would prefer to actually radiate most of the power they were generating.

Besides, how many times do you hear someone brag about their antenna in terms of how many cross-town contacts they made with it? It's always about how many DX stations they worked, or how far away they were able to reach. The ones who judge their success in terms of the stations they worked that they could hear simply have a poor criteria for it. Taking the point to an extreme ... at my previous QTH I could hear my neighbor with my rig connected to a dummy load and he could copy me when I transmitted into it.

I'm not really trying to argue with your general comments. You and I have generally taken the same positions on topics in these forums, so maybe I'm just being more picky on this one.

73,
Dave AB7E
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N2EY on March 31, 2009 Mail this to a friend!
N2EY previously wrote: "I think the "magic" of the ~43 foot length is that it's relatively easy to match on several bands, compared to resonant lengths....My main interest in this antenna is for Field Day, to give one of the stations a choice of dipole or vertical. If the site has a tree that can provide a single high support, a wire version could serve for 40, 20 and 15 with a simple L network at the feedpoint."

WA1RNE replies: "Jim, it may be easier to match - but for which tuner?"

For a simple L network tuner (one coil, one cap) right at the base of the antenna. If my semi-educated guess is anywhere near correct, the ~43 footer would be matchable on 40/20/15 (the bands of interest for FD) with just two control relays selecting taps on a coil and a single capacitor turned by an old screwdriver motor. Three control wires (ground, motor control, relay control) plus coax. Since the tuner at the feedpoint reduces the SWR to near-unity, the loss in, say, 200 feet of cheap coax is not a major factor. The high feedpoint Z reduces ground losses and the adjustability of the tuner means everything can be a little off and the system will still work well.

WA1RNE: "Manufacturers like DX Engineering are recommending the addition of 150'+ of RG-213 to bring the feedpoint impedance into a range that some tuners can handle more easily."

Well, I don't go for that approach unless some really, really low-loss coax is used, like Heliax or good CATV coax.

One big factor for me is overall system efficiency. If the higher efficiency of the big vertical over a quarter-wave trapper is lost in the feedline, might as well go with the trap vertical.

WA1RNE: "As you know, with the varitations in feedpoint impedance and very high SWR on some bands, the feedline is going to take a beating at 1500 watts and will likely fail. For Field Day it might be worth a try, but I would make that support 50' or better and elevate the feedpoint 7' or more, along with >= 4 radials per band and a tuner. That would be a fun project for a Field Day group."

For me, FD decisions are all about resources: what's available at the site, what people can bring, who is really going to do the work, etc. Elevating the feedpoint might not be worth the extra work. OTOH, people tripping over ground-mounted radials is no fun either.

Note that the 40 meter radials would be 3/4 wave long on 15 so probably only need 40 and 20 meter radials.

WA1RNE: "The article is very good but it didn't cover 2 very important aspects of this antenna:

1) Antenna tuner power handling over 100 watts on 40-10 meters and the challenges faced in feeding this antenna on 160 and 80 meters at even 100 watts."

IMHO, the cure is "tuner at the antenna". The article's data, even though based only on modeling, convinced me of that, particularly for 160 and 80.

WA1RNE: "2) Total System Cost"
Always a factor. In my case, the presence of a serious junkbox pushes toward homebrew.

As for high power, that's all part of the system design. For Field Day, the points penalty of high power is so bad that IMHO it's not worth it unless you've maxed out a lot of other options first.

73 de Jim, N2EY
 
The 43' Vertical -- a Theoretical Analysis  
by K0RGR on March 31, 2009 Mail this to a friend!
Thanks very much for your analysis. I'm considering one of these as an 'interim' solution for several reasons. Now, I think I can feel comfortable that my favorite bands - 40-30-20 will work well. Until the sunspots improve, that may be all I need to know.

I grew up using a HyGain Hytower 18HT. It was a great vertical. I wonder how well it would have worked with a lot of radials - I doubt that we ever had more than about 6 on it.

These 43 footers have an aesthetic advantage over the 18HT and most other commercial verticals. I think the Zero-Five would look very nice in my front yard. Or, I could install the much cheaper MFJ in the back yard and disguise it fairly easily.


 
RE: The 43' Vertical -- a Theoretical Analysis  
by WA1RNE on March 31, 2009 Mail this to a friend!
WA1RNE replies: "Jim, it may be easier to match - but for which tuner?"

For a simple L network tuner (one coil, one cap) right at the base of the antenna. If my semi-educated guess is anywhere near correct, the ~43 footer would be matchable on 40/20/15 (the bands of interest for FD) with just two control relays selecting taps on a coil and a single capacitor turned by an old screwdriver motor. Three control wires (ground, motor control, relay control) plus coax. Since the tuner at the feedpoint reduces the SWR to near-unity, the loss in, say, 200 feet of cheap coax is not a major factor. The high feedpoint Z reduces ground losses and the adjustability of the tuner means everything can be a little off and the system will still work well.


>>> Agreed, but I should have been more specific.

Today, there are very few hams who are homebrewing remote or external tuners. The vast majority of hams are asking which vertical to select or which tuner to select. Most correspondence I see pertaining to current users of 43 foot verticals involves problems using internal and external autotuners or external manual tuners used in the shack - none of which to date have indicated being home brewed. Very few users seem to bother with a remote commercially manufactured autotuner - never mind a homebrewed one.

Is a remote tuner worthwhile? Sure, and it would be a great project. The challenge is designing the right tuner configuration and control scheme and rounding-up the special parts, i.e. servo motors, relays, etc.


Otherwise, the rest of your responses seem to say or are pretty much in agreement with what I've said about the pro's and con's of this antenna.


About the elevated radials:

Using small gauge wire and some fiberglass or wood poles to support them would be easy. At 7' or more and with some bright caution tape attached every 15', the radials would be out of reach and very safe.

Compared to carpeting the Field Day site with wires for everyone to stumble over - or not carpeting with enough ground mounted radials - the elevated vertical will prove to be a winner in terms of performance, installation time and dis-assembly.


...WA1RNE


 
RE: The 43' Vertical -- a Theoretical Analysis  
by N2EY on April 1, 2009 Mail this to a friend!
WA1RNE writes: "Today, there are very few hams who are homebrewing remote or external tuners. The vast majority of hams are asking which vertical to select or which tuner to select."

That's sad, IMHO.

WA1RNE: "Most correspondence I see pertaining to current users of 43 foot verticals involves problems using internal and external autotuners or external manual tuners used in the shack - none of which to date have indicated being home brewed. Very few users seem to bother with a remote commercially manufactured autotuner - never mind a homebrewed one."

I think one of the purposes of forums like these is to change that "commercially manufactured" mindset. Particularly for simple stuff.

Look at what N3OX was able to come up with out of odds and ends to put his vertical on 80 meters without massive feedline losses.

WA1RNE: "Is a remote tuner worthwhile? Sure, and it would be a great project. The challenge is designing the right tuner configuration and control scheme and rounding-up the special parts, i.e. servo motors, relays, etc."

The FD antenna tuner I described would use a pair of common relays, the motor and geartrain from an old electric screwdriver, and some odds and ends. Since it's Field Day it doesn't have to be a permanent installation.

Could be a good club project, too.

WA1RNE: "About the elevated radials:

Using small gauge wire and some fiberglass or wood poles to support them would be easy. At 7' or more and with some bright caution tape attached every 15', the radials would be out of reach and very safe."

Yes, but that means a support at 50 feet or so, which may or may not be possible. And each radial needs a pole, plus the tuner is way up in the air.

WA1RNE: "Compared to carpeting the Field Day site with wires for everyone to stumble over - or not carpeting with enough ground mounted radials"

No need to carpet the site.

On Field Day, it's just common sense to put the antennas away from the stations, other antennas, and where people are. Particularly verticals. I cringe when I see things like FD stations located at the base of a temporary mast or tower, etc. Both for safety and interference issues, the antenna would be located out away from the station area.

For 40-20-15 meter FD operation, the longest radials would be 33 feet or so. That means a 66 foot diameter circle of radials, no more. Put caution tape around that circle on short sticks and the job is done.

I envision that the least expensive way to build such a vertical for FD would be to homebrew a 44 foot wooden mast of 2x2 (2x4 ripped lengthwise) with eyebolts at the top and bottom. Two 12 foot 2x4s, six bolts to make the mast, guy ropes near the top and halfway up, a piece of wire and some insulators for the radiator, some wire for the radials, a homebrew tuner and some odds and ends.

73 de Jim, N2EY
 
RE: The 43' Vertical -- a Theoretical Analysis  
by WA1RNE on April 1, 2009 Mail this to a friend!

Jim,

I OK with all your suggestions for using this antenna for Field Day. There are lots of ways to adapt this antenna and others for temporary use.


But the main application of the 43 footer isn't Field Day, it's home station use.

Many users expect to run greater than 100 watts at their home stations which isn't easily accomplished with this antenna unless specific system design considerations are taken into account.


...WA1RNE


 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on April 1, 2009 Mail this to a friend!
"Many users expect to run greater than 100 watts at their home stations which isn't easily accomplished with this antenna"

Actually, it's pretty easily accomplished with a bunch of attenuation between the antenna and the tuner ;-)

 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on April 1, 2009 Mail this to a friend!
AB7E says:

"I think that's basically my point. Many times the "I can work 'em if I can hear 'em" comment is used as a justification for settling for a poor choice in antennas"

Dave, we're on the same page as far as convincing people to use better antennas, but I've just seem a lot of people shut down and stop listening if you tell them their antenna is bad.

I think we need to frame it in the positive for maximum effect, and maybe you do that already when you're talking to them, but I think the slightest hint of anything that could be construed as snark or condescension tends to put people in a mindset where they feel like they need to fight with the "theory gurus" if they fill their log page every day with contacts.

Is it a "poor choice of antennas" if it's 8dB down from some easy alternative but they make a lot of contacts?

I think so. You think so. But people need to be softly convinced if they're to be convinced at all, from what I've seen. People get very defensive, and I think there are ways to sneak around that, but it's tricky.


73
Dan
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on April 1, 2009 Mail this to a friend!
"
Look at what N3OX was able to come up with out of odds and ends to put his vertical on 80 meters without massive feedline losses."

Worked pretty well too.

I wish I'd done the direct comparison. I planned mine out and built it before I'd realized how much of a phenomenon the 43 foot vertical with no base tuner was going to be.

My plan was "I want to use it on 80, and I want to be able to put it up and take it down in a few minutes," because I didn't know at the time if my landlord would be happy with me putting up antennas.

So I bought the pole with what I thought was the best ratio of height and strength to price and designed around it. Didn't realize I was on a bandwagon ;-)

73
Dan
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N3OX on April 1, 2009 Mail this to a friend!
By "direct comparison," I mean of course base matched vs. not
 
RE: The 43' Vertical -- a Theoretical Analysis  
by WA1RNE on April 2, 2009 Mail this to a friend!
"Many users expect to run greater than 100 watts at their home stations which isn't easily accomplished with this antenna"

Actually, it's pretty easily accomplished with a bunch of attenuation between the antenna and the tuner ;-)


>>> I stand corrected, thanks Dan!


...WA1RNE
 
The 43' Vertical -- a Theoretical Analysis  
by KU7I on April 2, 2009 Mail this to a friend!
This reminds me of a 33ft vertical I used in the 1990s. It was mounted on a 20 ft 4X4 and used four 33 ft radials in a ground plane, above ground fashion. I fed it with Radio Shack 300 ohm TV twin lead and used a Dentron MT-2000 tuner in the shack. It was a flame thrower on all bands 40 to 10, including WARC.

I ended up extending it to a full wave on 75 mtrs, roughly 60 some ft long, still vertical, still on a 20ft 4X4 and made the ground plane radials the same length as the vertical element. It rocked 80-10 mtrs. Fed it the same. Worked like gang busters.

Lane Ku7i San Diego
 
RE: The 43' Vertical -- a Theoretical Analysis  
by N2EY on April 2, 2009 Mail this to a friend!
"Worked like gang busters."

Compared to what?

73 de Jim, N2EY
 
The 43' Vertical -- a Theoretical Analysis  
by AD5FD on April 3, 2009 Mail this to a friend!
what the article told me was::

a use lmr 400 or better coax at low freqs. i was astonished at those db losses even with rg8 coax.

b use a tuned network at the antenna. very impressive. using that combination, a 43 footer should work fine.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by W8LM on April 4, 2009 Mail this to a friend!
I read with interest all the comments. The quest for the "silver bullet"- "Holy Grail" of antenna's continues.
I have yet to ever use a "store bought" antenna, except mobile.

Perhaps everyone is missing one thing...used to be known as an "Italian Vertical"

Take that 43' vertical or any other length for the most part and place a 100 watt light bulb across the feed point-at the end of the coax...

Mismatches are gone...you can load it in all bands, and make contacts galore..the claim is the light bulb reduces coax losses among others- blah-blah. Works the same if you place the light bulb in a coffee can so the neighbors don't see the blinking. Fact is that it offers a resistive load to the transmitter. We all used 100 watt light bulbs to tune the novice rigs in the 60's.

After we beat this one to death, Explain the "cobra" antenna sold in New England and some Ham Retailers..That has open wire feed and requires a tuner. I can only see a disadvantage to running 3 wires crossed back and forth over a fixed distance.

Regarding cost of antenna's including tuners etc...
A point- I used for years for FD a 15 meter 4 square..(11 feet high and 4 wire radials per element in a 16ft ring) Cost me $25 to build.. has 30 db F/B...6db gain.. Why do guys struggle with 30-50 ft of Rohn 25 ($500) a rotor ($250) and some store bought beam($299+++) and my $25 15M 4 square takes up same foot print, and works the same.. my setup is 1 man 1/2 hour.

One issue I will contend. The tuner needs to be at the end of the coax..mine is...3 ft coax.. the rest is 450 ladder..

I have had great success with ladder line even running up the middle of Rohn 25. I have always placed a twist of about 1 turn per 12-18 inches. The reason for the twist is the same reason Cat 5 cable is twisted. The claim is interaction with the outside world (like running down the middle of Rohn 25) is reduced or eliminated.

So gentlemen please beat to death my twisting of 450 ladder and conclude with me the "cobra" antenna is poorly designed/engineered.

Punching me in the nose requires a trip to Wichita, Kansas..
73's --wake the SUN I want to play DX radio.
Larry W8LM ARRL Life member.
 
RE: The 43' Vertical -- a Theoretical Analysis  
by W7AQK on April 7, 2009 Mail this to a friend!
HFRF says,in effect, that since only modeling is used to "analyze" this vertical, his dummy load must be a good antenna since it is always 1:1. If that's true, why don't you model it for us? I would like to see the radiation pattern, gain, etc. for that.

Antenna modeling is not perfect. There are always "conditions" that either aren't correctly described in the input data, or aren't contemplated at all. There are always some things the software cannot deal with effectively. However, I think modeling software like EZNEC is reasonably informative about what MAY be achievable, and it is particularly informative when drawing comparisons between antennas where like conditions are inserted for each antenna being compared.

It seems to me that HFRF is discounting antenna theory itself, since software like EZNEC is merely trying to make visual representations of what antenna theory tells us should happen. In other words, it makes the calculations based on known laws of physics, and paints a picture of those calculations.

Dave W7AQK

 
The 43' Vertical -- a Theoretical Analysis  
by KB0UXV on April 9, 2009 Mail this to a friend!
Thank you for the article. As a 43 foot owner, the only thing you missed was the option of the remote antenna tuner. I use a remote tuner with great results, but of course this does not change the radiation pattern problems above 17 meters.
 
The 43' Vertical -- a Theoretical Analysis  
by K2PI on April 12, 2009 Mail this to a friend!
Good article Dave. I for one liked reading the theory behind the antenna.

I actually have one of these - the DX Engineering version. I am somewhat constrained in what I can put up - not with covenants, but with time and space. I was using several antenna's for the past few years: A commercial buddipole (admittedly a compromise), a trapped dipole (same) and an 84 ft. doublet fed with ladder line suspended at about 35 feet. All of them performed more or less ok, but there were many stations I could not hear, even when everyone was working them. Working those stations was also a challenge.

I also play around with WSPR at very low power levels (500mW or less). On my old antenna's, I would routinely receive reports from the east coast and around the EU with SNR's between -23 and -15. The first day using this antenna, my average SNR jumped to -10 for the east coast, and +0 or so around Europe. I am also heard by ZL and VK over and over, something that happened only rarely on my other antennas. All at 500mW.

In the two weeks since I ground mounted this antenna, and laid out less than 10 radials (more to come) I have worked about 12 new countries, and really do seem to be able to work just about whatever I hear. The take-off angle and capture area seem to be giving me much better results than the other antenna's. It is also actually quieter, since all but the buddipole required me to use the house for a mount, and operating here in the UK, the power line noise radiated from the homestead is just atrocious.

So, even with a particularly poor set of radials, and fed initially with 75' of RG-8X (since changed to 9913) I was very impressed. I know without a doubt it beats my old butternut, probably by virtue of height above ground alone. Theoretically poor or not, the antenna performs as good as anything I've had up in the last few years. It's not a 5-element monobander up 100 feet, but I am very happy with it nevertheless.

73,

K2PI / M0DUO

 
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