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[Articles Home]  [Add Article]  

The Inverted Hell Antenna

from Randy Cook, K6CRC on January 22, 2019
View comments about this article!

The Inverted Hell Antenna
(Mother Nature gets back at me)
By Randy Cook, K6CRC

I have been a Ham for about a decade now.

Not counting my very short time as a Novice in High School in the 70s. Pre-empted by a car and a girlfriend. Left no money for a ham rig. Cars can do that, and girlfriends WILL do that.

Sorry I digress, back to Ham radio… When I FINALLY got my General back in 2007, I faced the decision about a permanent antenna. Having a small lot on the edge of the Santa Cruz mountains, my options are limited.

I started with a couple of end-feds between my roof and the 50 foot tall Redwood trees at the back of my yard. Limited my bands, but they got me on the air. With sunspots on my side, I worked the world.

One day, my neighbor in the back mentioned the retaining wall we share as a fence seems to be bending a bit. That wall is what keeps my yard and the Redwood trees from landing in her living room. And inspection was performed - the conclusion was the beautiful trees, and my antenna supports, had to go. In California, dropping a couple of big trees subjects you to all kinds of criticism, even protests, from those who see other living things as more important than people.

My little old lady neighbor down the street, the one with all those cats and that beat up Volvo, was shocked as the Arborist removed ‘those children of the Mother Nature’. Even reminding her what a couple of mature trees would do to my ‘Mother Neighbor’ if they fell didn’t dissipate her anger. ‘She gets HER revenge, you know!’ as she wagged a finger at me.

Back to the antenna plan. I asked a lot of people on forums and such for suggestions. The most popular recommendation was to try an Inverted L. I could put a SpiderPole in one corner of the lot, and run the horizontal wire across the yard to a smallish tree near my other neighbor’s fence.

With the Redwoods removed, the back yard was re-landscaped. Simple matter to put down conduit for a long coax run to the SpiderPole from my rig. The design would have 30 foot vertical and as much as 60 feet horizontal sections, and I could lay down a dozen radials, but only in a 110 degree pattern.

More research gave me a neat solution. A 9:1 Unun and a ‘magic’ wire length could give a low SWR on all HF bands, with minimal ATU help at my rig. Several specific lengths seem to create SWR dips at or near HF Ham bands. One of those magic lengths, 84 feet, would fit perfectly.

OK, pole up, wire in, radials down, LMR400 coax run. Picked up a Balun Designs unun with both 4:1 and 9:1 taps. Added a line isolator at the rig end. Beautifully made products from Balun Designs, by the way.

Plan was simple. Set unun for 9:1. Get a SWR meter, and adjust wire length for lowest reading on 80M. Other bands would fall into line with low SWRs, as several people told me. After cutting for 80M SWR bottom, I moved from 10M down on my RigXpert analyzer. The process seemed to be working. Then, I hit 40M and the SWR went to the meter limit of 10.

Strange! So I tried trimming the antenna length for minimum SWR at 40, and the HF bands all fell into line EXCEPT 80M. SWR was over 9:1. Huh?

People whom I had been getting advice from were confounded. I must have done something wrong, likely a simple mistake. I tried literally every possibility. More radials, shorter radials, isolate coax at the antenna end or the rig end. Tried other ‘magic’ lengths, 53 feet, 71 feet. I get the higher HF bands tuned OK. But, either I get 80 or I get 40 usable. Not both. Moved unun to 4:1, but that didn’t help much.

I was just standing by the SpiderPole trying to figure out what I was forgetting. Then, the wind whipping through a neighbor’s trees made what sounded like a laugh. Mother Nature was mocking me!

After working down every suggestion and idea, I just gave up. My solution? Bought a remote tuner and put at the antenna end of the coax. I can now tune any HF band with a low SWR. Tuner seems to work best with the unun in place and set at 4:1.

I am happy with my set up, but still wonder why MY antenna was the one that didn’t follow the rules that worked for others?

‘Revenge of Mother Nature’, perhaps?

Wait, there is that noise in the trees again, it sounds like laughing…

Member Comments:
This article has expired. No more comments may be added.
 
The Inverted Hell Antenna  
by N9AOP on January 22, 2019 Mail this to a friend!
Your house isn't built over an old cemetery, is it?
Art
 
RE: The Inverted Hell Antenna  
by NO9E on January 22, 2019 Mail this to a friend!
You may try to read the ARRL antenna book.

Many hams are absorbed by antennas that have low SWR. Actually they should be absorbed by antennas that radiate well, with matching left to ATU. Personally, I had many antennas that had very good match but were many times weaker than nonresonant antennas matched by ATU.

Dipoles/endfeds radiate better when high and flat. But they have lots of lobes on higher frequencies so working some countries is easy and some difficult.

Verticals radiate well with many radials when soil conductivity is high and with few obstructions. For high frequencies (over 5/8 lambda), radiation is mostly up, no good.

The best way to find good antennas is to have at least two with ability for fast A/B switching.

Any piece of wire is good for FT8.
In your case, a 40m dipole fed by ladderline or TV line and matched by tuner may be the best choice. With Spiderbeam try thinner wire (20-22) to avoid drooping.

Ignacy, NO9E
 
The Inverted Hell Antenna  
by DL8OV on January 22, 2019 Mail this to a friend!
An antenna with the antenna tuner at the end of it THEN the feeder is the correct way to do it, but people seldom do as external automatic tuner are expensive.

Peter DL8OV
 
The Inverted Hell Antenna  
by WA9AFM on January 22, 2019 Mail this to a friend!
It appears your ATU is at the base of the antenna. What's the make/model and how do you power it?
 
RE: The Inverted Hell Antenna  
by KB1GMX on January 22, 2019 Mail this to a friend!
>>> but still wonder why MY antenna was the one that didn’t follow the rules that worked for others?<<<


Because myth and lore are not physics.

The "majik" length end fed with 1:9 transformer is
an antenna where neither end of the cable is ever
matched. There is a mismatch of the wire to the
transformer as the wire is likely never 450 ohms
and also likely reactive. Then at the other end
of the coax your still not 50 ohms and you can bet
its reactive as well. So the cable is part of the
matching system and likely if that's not a
"majik" length its going to interact in very
strange but actually predictable ways.

Coax is always transparent (save for loss) if both
ends are matched. When they are not it does things
like at a electrical 1/4wave a short at the far end
looks like an open at the near end but at twice the
frequency (electrical halfwave) the impedance at
the far end is echoed back. Those are the simple
cases... For odd lengths and frequencies it can be
calculated if you know what the far end is doing.
So tuning a random wire then becomes confusingly
difficult without actual R,jX measurements of the
antenna for a given frequency and a calculator and
likely a willingness to cut or extend the coax. Its
the stuff of optimizing computer programs and source
data from network analyzers.

In the end you went back to a matching network (tuner)
fed antenna, matched to the coax feed line and cut
the problem off at the knees thus not incurring feed
line loss and other problems.

For years I had an inverted L fed with a box at the
base and a handful of relays to match it to 50 ohms.
The relays selected the needed L and C to make the
Match look good for the bands being used and the
antenna performed well. Took a lot of time to tune
it for each selected band but it was far cheaper than
a auto tuner. Control was Via bias tee and varied
voltages and polarity.

Yes, do read the ARRL Antenna Book(s).

Allison


 
The Inverted Hell Antenna  
by AJ4SN on January 22, 2019 Mail this to a friend!
I use an inverted "L" antenna: 33' vertical and 80' horizontal. The ground radials cover only about 180 degrees. My matching system is at the base. It is a great antenna, but it can be particular about matching. I think that this is because the feed line often picks up common mode currents which make the matching unpredictable.

73,Stan
 
The Inverted Hell Antenna  
by KJ6ZH on January 22, 2019 Mail this to a friend!
With the antenna tuned for 80m, I would add a second wire from the Unun about 28-30 feet and run it up your support pole or angling away from it to form a square root antenna (looks like the mathematics symbol). I have one set up at my QTH for my Inverted L on 80 with a 4:1 Unun and can tune 80, 40, 20, 17, 15, 12 and 10m with reasonable SWR at the radio <4:1 on 80 and <1.5:1 on other bands. SWR is high on 60 and 30 m but the rig's tuner will tame it.

Not real worried about a 4:1 match on 80 as line losses are low at that band.

73
Chris KJ6ZH
 
RE: The Inverted Hell Antenna  
by K6CRC on January 23, 2019 Mail this to a friend!
A 'tongue in cheek' sort of article...but being about antennas will no doubt start minor skirmishes. Almost as bad as mentioning code requirements or HOAs.

I was hoping to be able to tune the antenna AT the rig, but anything over 3:1 won't work. So, I put a MFJ remote tuner, powered on the coax, at the feedpoint. I corresponded with many hams and several vendors about my situation. different opinions, many contradictory.
ARRL Handbook and 'Small Antennas for Small Spaces' were helpful, as was info on Balun Design's website.
In any case, it all works. And, it was a great learning experience.
Thanks for the comments.
 
RE: The Inverted Hell Antenna  
by KJ4DGE on January 23, 2019 Mail this to a friend!
All in all the point is he made it work. Thats the point of the article and thanks for the fine points about the lady with the wagging finger, I had one of those folks once as well and yes check to see if you have native Americans under your backyard, they love to mess with antennas even from the "other side" :)
 
The Inverted Hell Antenna  
by W9YW on January 24, 2019 Mail this to a friend!
My first tree antenna was a wonder. Worked the world. More recently, there is the 75+ foot sycamore that I want to use, and my neighbor says: Sure.

There was the drone that I tried to use to lift the fishing line over the top. One motor in the drone had inherent drag, and with the short flight time, it would never go in the right direction for more than 3sec.

Then the slingshot was tried. The physics were that the fishing line could not meet the spontaneous torque needs and the fishing weights are somewhere in the next county.

Followed this with a dream PVC tennis ball launcher. It has a trigger and everything. Looked sure fire. Fed it nearly 110 pounds. This might hit the Atlantic Ocean we thought, when we tested it on a friend's property, whilst aiming over his house. The trigger mechanism seems faulty/leaky and it can barely get the ball out of the barrel, emitting the sort of sounds that make most audiences blush. Key of G, I think.

When it thaws a bit, we're going to have resealed everything, but we suspect that his cherry tree, and my sycamore are in cahoots with your redwoods.
 
RE: The Inverted Hell Antenna  
by K9MHZ on January 24, 2019 Mail this to a friend!
"Yes, do read the ARRL Antenna Book(s).
Allison"

Definitely, they're excellent. Anytime a feedline is designed to, or just acts like a part of the system itself, it's pretty lame. But I'm sure J Pole and G5RV fans would disagree.
 
RE: The Inverted Hell Antenna  
by G3RZP on January 24, 2019 Mail this to a friend!
>>> Anytime a feedline is designed to, or just acts like a part of the system itself, it's pretty lame.<<<

Would you include curtain arrays in that statement?
 
The Inverted Hell Antenna  
by N8XI on January 24, 2019 Mail this to a friend!
I had a previous INV L fed with coax for 80M then in 2005 I erected an INV L 35 feet Vertical then 90 feet attached 20 feet above ground to a telephone pole.
Fed directly about a foot off the ground with 450 ohm Twin Lead.

I have four 0n the ground radials 2 - 65 feet running through the shrubs running north turning west and looped back on themselves.
The other two run south in front of the QTH
then west and are attached to the top rail of my chain link fence. I don't know how long these last two are.

But, the chain link fence connecting all the neighbors in the area is probably a couple miles long.
This lash up used to work on all bands 160M thru 10M including the WARC bands using a Ten Tec Model 238 Antenna Tuner...
But about 3 years ago this setup became unusable on 160M...Still usable on 80 thru 10 including WARC...
I just threw the thing together and it worked...To my surprise!!

73, Rick - N8XI
 
RE: The Inverted Hell Antenna  
by K9MHZ on January 24, 2019 Mail this to a friend!
"Would you include curtain arrays in that statement?"

Geez, I guess not. And lots of techniques to broadband a design...open-wires are nice, and I've been envious of those guys who can pull it off nicely.

But there's a context here, don't you think? Just hate seeing new folks especially, being lured into a "magical" antenna configuration without any clue about the role of the coax itself. You've been around long enough to sniff out snake oil.
 
The Inverted Hell Antenna  
by WA5VGO on January 24, 2019 Mail this to a friend!
Where does the myth that SWR is an indication of antenna performance ever come from?
 
RE: The Inverted Hell Antenna  
by K9MHZ on January 24, 2019 Mail this to a friend!
It's easy, probably too easy. Hook up a cheap meter, and you an get a warm fuzzy. Smith Charts, antenna efficiencies, patterns, etc require a lot more work.
 
RE: The Inverted Hell Antenna  
by KJ4DGE on January 24, 2019 Mail this to a friend!
Wow, being something of and old nerd I never thought we would in our retiring years argue over who had a longer pole, wire, extended length of antenna, sure some of us had children but we are talking the finer points of our relationships with a wire antenna, bet our wives have something to say about that :) not trying to be a party pooper but please, its about what works!
 
RE: The Inverted Hell Antenna  
by K6CRC on January 24, 2019 Mail this to a friend!
KJ4DGE sez 'not trying to be a party pooper but please, its about what works!'
My feelings exactly. I have a friend who has designed antennas for 'three letter' agencies. Not a Ham. I asked him about 'modeling' my antenna, and he laughed.
'Between the neighbor's wavering trees, the house behind yours, the seasonal changes in the soil, crappy radial system, bending fiberglass SpiderPole, and a grumpy Mother Nature, I wouldn't even bother. If it works, just enjoy it'.


 
RE: The Inverted Hell Antenna  
by K9MHZ on January 24, 2019 Mail this to a friend!
Well, you can say that for just about every one of life's pursuits. A bicycle will get you down the road just as easily as a Mercedes, a cell phone takes pictures just like the big boys at the game, a Heathkit gives you just as much enjoyment as a IC-7610, and on it goes.

Nothing wrong with enjoying mediocrity, I suppose. Learning something and seeing a good design come to fruition is pretty enjoyable, too.

 
RE: The Inverted Hell Antenna  
by N8XI on January 24, 2019 Mail this to a friend!
Darrell, WA5VGO

Yes I once had a light bulb for a Dummy Load.

Loaded up mighty fine and had a low SWR.

In fact, I made a few QSO's.

But a good antenna, it never made :(

73, Rick
 
RE: The Inverted Hell Antenna  
by NG1H on January 25, 2019 Mail this to a friend!
"Where does the myth that SWR is an indication of antenna performance ever come from?"

Generally for antennas of the same design & installation the one with the lowest SWR will be the best radiator. People then take this one case and assume the same general rule applies to all comparisons.
 
The Inverted Hell Antenna  
by WA7ARK on January 26, 2019 Mail this to a friend!
The reason that the author's Extremely-Off-Center-Fed antenna (I refuse to call it an End-Fed-Antenna, 'cause it isn't) did not resonate on its second and higher harmonics is well explained in John Huggins Blog:

https://www.hamradio.me/antennas/lnr-precision-ef-102040mkii-examination.html

If you resonate the antenna in the 75m band, you would have to add a small coil in series with the antenna wire about 10% from the distal end to move the SWR dip into the 40m band. This would also better align the SWR dip on 20m.

The commercial versions of this type of antenna come with the coil so as to make them useful on at least 80m, 40m, 20m and some higher bands.

 
RE: The Inverted Hell Antenna  
by K0UA on January 26, 2019 Mail this to a friend!
By the way, I have never seen a tree high enough that my simple Joplin Amateur Radio Club pneumatic launcher would not shoot a line over. Granted I don't have giant redwoods here in southwest Missouri, but pumped up, I am not sure it wouldn't shoot over one of those.

Pneumatic launchers work, and they work very well .
 
The Inverted Hell Antenna  
by WA2VTA on January 28, 2019 Mail this to a friend!
I moved to a condo about a year ago, and obviously needed to contend with restrictive covenants. Basically, I can't erect an antenna!

Well I did anyway. I hung an 86' random wire - one of the "magic" lengths - and fed it with LMR-400 low-loss coax and a 9:1 UNUN. The antenna is meandered around my deck, underneath my vinyl siding, and through various other structures, and the highest point is only about 25' off the ground. It is virtually invisible unless someone was specifically looking for it.

The auto-tuner on my rig - an FTDX-1200 - tunes it on EVERY band - 160 through 6. I run under 100 watts CW and SSB, and regularly make contacts all over the US, Europe, and South America.

For a ham, there is no worse antenna scenario than mine. But I researched, tinkered, and made it work - the essence of ham radio. Don't get me wrong - I'd love to be running 1000W and a 6-element beam on a 100 foot tower. But that's just not happening.

Good luck - I know you'll figure out your best possible arrangement, as I did.
 
RE: The Inverted Hell Antenna  
by K6CRC on January 28, 2019 Mail this to a friend!
'Good luck - I know you'll figure out your best possible arrangement, as I did.'

I can say this about my antenna:
A compromise? Definitely.
Efficient? Likely not.
Optimized? Doubtful.
Nearly invisible? Yes, and has kept me out of divorce court.
Does it work? Over 200 DXCC entities and 5BWAS, so that is a Yes.
Can I do better? Well, I will continue to try.

 
RE: The Inverted Hell Antenna  
by N3WNG on January 28, 2019 Mail this to a friend!
Take a look at the Joplin ARC launcher (Google will get you there). I tested it out this am and it works great. Will put an end-fed up in the next day or two using it. FYI....I have no connection to this club other than this purchase.
 
The Inverted Hell Antenna  
by AA4MB on February 2, 2019 Mail this to a friend!
WA9AFM: look on LDG's web site. Not only do they make a couple of very robust remote tuners, but their secret weapon (my opinion) is the little Z11 Pro II tuner. I power mine with batteries (qty 6, 1.5 volts) and have it mounted in a plastic box I bought at Target. I put holes in the bottom, so rain water doesn't get into it. If I'm not mistaken (and if I am, someone on here will glefully tell us so!) it only pulls 25 microamps when it's not actually tuning. It uses latching relays, so if I'm still on the same 40 meter CW frequency tomorrow as I was when I shut the rig off today (or close to it, even) it doesn't need to 'tune' tomorrow, until I change frequency significantly. I replaced batteries in it about 6 months ago and between rain storms this weekend, I'll try and be proactive and put new ones in there, and it should last another 6 months or so.

My antenna goes up 20 feet vertical, and out maybe 45-55 feet or so (no, I haven't measured) horizontally. Works like gangbusters, except for 160 meters. Even though I get an impedance match presented to the coax that is acceptable, it's just too short and too low to be very efficient on 160. It's fairly good on 80, and I'd qualify it as a very good radiator on 40 and 30 meters, too. I don't frequent bands higher than that right now, with sunspots being nearly non-existent.

WA5VGO: you're right. Antenna efficiency vs SWR can be a very interesting discussion topic. I don't know about 30-40 years ago, but nowadays obsession with SWR is likely motivated by the fact that our awesome solid state 100 watt rigs fold back the power pretty quickly starting at an SWR of 2.0 to 3.0 or so at the rig's SO-239 - depending upon the rig, of course. In a big hurry, your ERP can be at QRP levels if you're running the rig into much of a mismatch. I prefer the remote tuner, because the higher in frequency I go, matching the impedance at the rig (internal or external tuner) starts to give you mounting dB losses going through a mismatched feedline. I'm sure that most people on here know this, but years ago I learned it the hard way and I'm hoping someone has a V-8 moment and looks into it for themselves if they don't already know it. Oh for the days of tube finals which really didn't care that much about the SWR which was presented at the rig's coax connector! Man, in my early hamming days I'd load into anything - no tuner, no brains on my part, either - and let it rock. Can't much do that anymore with the new rigs ...
 
RE: The Inverted Hell Antenna  
by KB6QXM on February 11, 2019 Mail this to a friend!
It is simple. The reason why K6CRCs antenna did not follow the rules is that the antenna is located in California.

No matter if it is following the rules of physics, it does not matter in California.

The laws of physics would have to be changed, regulated or taxed in California or new physics laws would have to be written to meet California standards.

For all of you that are about to flame me. This post was sarcasm. I am a multi-generational native Californian and who lives the "California dream" daily. (If that is what you want to call it!)
 
RE: The Inverted Hell Antenna  
by K9MHZ on February 12, 2019 Mail this to a friend!
"I am a multi-generational native Californian and who lives the "California dream" daily. (If that is what you want to call it!)"

Sorry to read that. Anyway, the Inverted L is described quite well in the Antenna Handbook, page 9-29. Pretty boilerplate info.
 
RE: The Inverted Hell Antenna  
by KB6QXM on February 13, 2019 Mail this to a friend!
@K9MHZ,

Let's just say it is not the same place that I grew up in.
 
RE: The Inverted Hell Antenna  
by K9MHZ on February 13, 2019 Mail this to a friend!
Yep. Lived there for 7 years, and leaving was the best move I've ever made. Sad, such a beautiful state.
 
The Inverted Hell Antenna  
by WA0LYK on March 8, 2019 Mail this to a friend!
I am at a new location and needed a simple and easy antenna. I ended up with a 170 ft. Wire, about 40 ft up and 130 ft horizontal at about 25 ft. Fed it with a 9:1 unun and an isolator at the bottom and one at my rig, all homemade for a kilowatt.

I don’t need a tuner on 17 meters and above. The rigs tuner works fine on 40, 30,20, and the low end of 80. I use the Ten-Tec 238 on the rest of 80 and all of 160 and when I use the amp. I have six 70 ft radials in 180 degrees under the wire. The SWR is not very good below 20 meters, up to 5 - 7.

This is the best wire antenna I’ve used other than resonant dipoles. Low noise, receives well and not too directional.

I started with end fed 60 ft up and over the tree and no radials, just a ground rod, and the unun only. Very noisy, poor receive, not real good signal reports.
 
The Inverted Hell Antenna  
by K6JEK on March 13, 2019 Mail this to a friend!
Important rules of thumb:

It's not worth pissing off your neighbors for less than 3dB (N6DVD).

A vertical antenna is a great way to meet you neighbors. You'll broadcast into everything (K6GLH)

How much makes a difference? 2 dB makes a difference (N6BT)
 
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