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[Articles Home]  [Add Article]  

Smaller Backyard, Revised 40-Meter Beam!

from Bob Raynor, N4JTE on July 28, 2014
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Smaller Backyard, Revised 40-Meter Beam!
40 Meter 3 element reversible vertical wire beam
Submitted by N4JTE

Things have changed in my neighborhood! A family from LI. NY now occupies the house/backyard next store, which had been vacant for years. Why anyone would move from Babylon to Ellenville is a question I will ask as soon as I finish taking down my “annoying” string ends from his newly acquired backyard trees.
Say goodbye to an amazing 80 meter reversible wire beam , a 40 meter EDZ and one lousy string on 40 wire beam intruding! Yeah yeah truth be told, I was a spoiled little brat that lost his antenna playground, hi
My yard is only 48 ft wide in a north south direction so once again necessity being the mother of invention; let the adventure begin.

The Plan:

I wanted to at least match my 40 meter 2 element previous existing wire dipoles beam’s excellent performance based on ¼ spacing and was/is a full length reversible flat top at 40 ft as seen on my qrz page. With only 48 ft of space now available, it was time to shrink everything to be able to fit in my yard.
Heck, even without my adventuring into the 3rd element this baby at two elements with only 16 ft spacing will double your ERP in reversible directions with 30 db front to back!! Yada Yada; as per all the books at least, hi.
Note; Yes this will be a rather “technical” article in which I will present a bunch of stuff that will hopefully resonate with a few antenna nuts on the same path that I have been navigating for many years.
And, I am confident that there is some good info presented here for anyone who wants a tremendous mono band cheap antenna with useable gain and substantial front to back in relatively small backyard.
And please note that this monoband phasing concept can be extrapolated for any band from 160 meters to 2 meters.

HOWEVER; If you want a 6 band, I hear everywhere, “tunes ?” all bands dc to daylight DX buster antenna, or a 7 ft. tall antenna on your kitchen toaster for 10 bands, than stop reading and head off to ”Ham Universe.com”or some other magic antenna site.
Study this chart and begin the adventure into phased vertical and wire dipoles!
Spacing in W/L between elements is on the top and phase angles are on the side if diagram is hard to read as eventually posted here.


Figure Polar plots of spacing vs phase angle with resultant gain over a single element.

I have used two element vertical driven arrays, and lately, dipole phased driven arrays on 80, 40 and 17 meters for years with amazing results based on 1/4wl spacing with quadrature Christman feeding utilizing ON4UN and VK1OD’s feed line studies. Their work proved that 84 degrees works better than 90 degrees with a lag/lead line of 71 degrees adding up to 155 degrees. Having tried the 90 /180degree versions, I can attest to the 84/155 degrees being lights out better! -- Especially in flattop dipole configuration. However, I never had the need till now, to go back to a vertical design, at a new to me, 1/8wl spacing, with non (90 degree) quadrature phasing, so it came down to the usual build it and see what happens exercise!
I have used many variations/ number, of raised radials in the past and decided to use just two in this experiment. Reason being I knew I could real time test it against a two wire beam and it's too darn cold for more!

Well, back to my new limitations, that extra tree or two in my new neighbor’s backyard are now off limits, so what to do?

Besides nasty thoughts of directing a couple of skunks into his living room or worse, to welcome them to the "country", common sense prevailed.
I have often been intrigued with 135 degree phasing as it is the optimum end fire gain achievable on any 2 element system be it vertical or horizontal. Best part is the slightly better gain and front to back with only 16 ft of spacing on 40 meters. My plan was to build the 2 element phased system with 1/8 WL spacing as inverted vee’s, and when optimized and tested the next step was to be adding a switchable parasitic director/ reflector vee as a third element! Spoiler alert; after many hours of construction the two element inverted vee configuration was an abysmal failure! No front to back even with forced phased feeding so it's apparent the Vee configuration is not the way to go with 1/8 wl spacing!

Quick Phasing Primer:

I have been singing this song about phasing in previous eham articles and extolling the virtues intrinsic to the design and have seen a growing interest from many emails from around the world who have heard and worked me especially interested in my use with dipoles as opposed to verticals, as the ground losses of dipoles at 1/4wl plus tall, are minimal as compared to the average vertical install.

Achieving all those wonderful gain and pattern pictures in all the antenna books will only be achievable if the voltage/magnitude is exactly the same on both phase lines at the element wires. There are a couple of sweet spots on the coax but never exactly at the published polar plots phasing numbers like the ones pictured above from the ARRL antenna books.
Case in point; a 90 degree spaced cardioid end fire needs 84/155 degrees to reach design paradigms.
And 135 degree phasing is actually happier with 157/39 degrees with 1/8wl spacing as shown below on the polar plot from ON4UN's book.


Figure 135degree phasing with 16ft spacing.

157 degree phasing with 39 degree lag line
3 db beam width=142degrees
Gain=4.3dbd

So, with the new backyard constraints and after the Inverted vee fiasco, I figured why not try out the 1/8wl spacing with two full size vertical elements and then add a switchableparasitic 3rd element director/ reflector for maybe even a super ah ah moment. -- About same East/West footprint as previous 2 element wire beam. My center frequency of choice is 7160 so the following formula plugs that number in along with needed phase line degrees, no need to worry about velocity factor except when picking starting length of coax.
Caveat; do not cut phase lines based on VF alone without doing the frequency method, waste of time and accuracy!

Formula: 157/90 = 7.160/X = 4.104 meg

That’s the frequency, 4.104 meg that you want to see the lowest SWR displayed when trimming the 157 phase line lengths. Remember this method requires the ends shorted when using transceiver with 50 Ohm dummy load in parallel with tested feed line.

Scan the vfo, run around 30 watts on rtty until you find the sweet spot/ lowest swr, remember a low frequency tells you that your line is still long, that’s a good thing, tedious but effective! The 39 degree line lag/lead line for reversibility is figured and cut with the same method for a frequency of 16.4 Meg. This formula gives you the means and method with your transceiver to cut phase lines correctly without expensive test equipment.
I got this epiphany/formula about 6 years ago and I have concentrated on phased experiments since then. And when you build one you’re going to be as addicted to phasing as I am!
I put in the two 4x4 pt poles at 16 ft. spacing and a third in the west direction at 20 ft. spacing for the future parasitic director/reflector. Big guess on that parasitic dimension with phased elements involved when reversible!


And then the weather showed up big time!

Time to cut the phasing lines and elements inside, 5 degrees out there! That’s 10 unwelcome inches of snow!
All element poles are spider poles from the previous 80 meter wire beam and were eventually 43 ft tall and strapped to the 4x4 posts with no guying needed as at that height the 60 ft spider poles were nicely nested and stable in the wind at 43 feet. The wire elements are 33 ft with two raised radials at about 10ft off the ground.

Results:

Had enough left of the flattop 40 wire 2 element beam to compare the new vertical antennas in real time. Neighbor has not seen the one remaining masonry string still over there yet, hi. With just the two vertical elements in the new configuration it was definitely noisier in the East direction than the flattop, that building 50 ft away in the photo is an extended care facility with lots of medical noise. Signal strength reports in Europe were a couple of S units down from flat top so there was a little drop off with the new smaller footprint design and change of polarization.
The original beam is E/W and the new one is now NE/SW, so one never knows if that figured in.
BUT:
With the addition of the switchable director/ reflector the differences were not really a big deal, some nites the verticals beat the horizontal and vice a versa. The extra parasitic element was the big equalizer in getting closer to 2 element horizontal beam performance.
The parasitic element was the biggest challenge, radials or not etc. Going from the 30 to 36 ft length, director/reflector, with the relay was a no brainer but tuning it up near 7160 was a chore because I figured I needed radials or something for the other half of a non-driven thingy as I up to now, never had any real, write home about, performance from parasitic vertical, multi element designs. I kept the length of the director wire at 30 ft. and added one 33 ft. long radial laying on the snow and trimmed it till I got to 7518 (director) using a separate feed line back to shack to check for freq/swr. I have the MFJ and Autek analyzer but way too cold! Strange approach but hey it worked, (till the snow melts!). Then I attached the relay along with 6 ft. of extra wire to the vertical wire to make it into a reflector.

I was worried that with an additional element the front to back/gain would be impacted, and it was, for the better. The 3 verticals do not have the usual 25db front to back that the 2 dipoles showed, but similar gain, a fair trade off in tight space.
I am aware that the parasitic vertical element will probably work even better with some due diligence as at this point it is a low inverted L!
Actually most things I try are a big guess until in the air! Not a very good modeler with real world phase systems and unknowable near and far field enhancement on verticals. Also this time every year while I am writing this, mid-February after dark from Hudson Valley, NY, the band is horrendous/ qsb etc. stateside but still relatively good out east and long path to VK. -- Absolute worst time of year to try a new antenna design on 40 meters from NY but no choice.
Obviously a two element reversible monobander, even at 40 plus feet, is hard to beat but this experiment been has convinced me of what can be accomplished in a small backyard with 1/8wl spacing for 40 meters.

If you build it: 1: All wires 12g insulated and each of the two phased elements are 33 ft. long, the two raised radials on each of those elements were not measured but were tuned for 7.160 as low dipoles.
2: Phase lines at 157 degrees and 39 degrees are rg8x. -- About 48ft.long and 12 ft. long respectively.
3: Optional dir/ref is 30ft long wire, (give or take, never measured it after tuning) with a dtdp {could be spdt but have lots of the dpdt12v relays laying around} with 12 volt relay at director length bottom with 6ft added at the normally off terminal for needed reflector length. Both relays when normally off, were for West direction and switched from shack 12 volt supply with $3 light switch on ground leg to add reflector length and lag line for East direction. Radio shack relays used are sold online at around $6.
4: I use the LDG auto tuner but a matching network of parallel ¼ wl 75ohm coax feed line probably easy to do.
5: Relay wiring is available on my QRZ page and previous eHam articles.
6: Radio is IC 751a with ICM microphone and AL80b amp usually at 600 out.

Final thoughts:

The soon to be removed 2 element flat topped phased dipoles, http://www.eham.net/articles/26865 will be missed but this vertical design has achieved very satisfying results in a much smaller space.
I believe that getting a two, or the optional parasitic 3 element, widebeam width, reversible high gain, low angle short "boom" vertical beam is very achievable on 40 meters in a typical backyard and of course it all gets easier and smaller when designed for the upper bands.
With a little sweat equity you can compete very effectively with any store bought tower and commercial trapped beam costing probably 20 times as much.


The alternative!!!

Tnx for reading
Bob
N4JTE

Member Comments:
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Smaller Backyard, Revised 40-Meter Beam!  
by W7ASA on July 28, 2014 Mail this to a friend!
Good article and well written! Your link to the phased dipoles came at the right time for me, because I have a regular sked on forty at the same time that forty comes in from Europe ont he back azimuth. It would be great to put gain on the sked and a null on the undesired signal path - best for both sides of the Atlantic.


73 & Thanks,

Ray

W7ASA ..._ ._
 
Smaller Backyard, Revised 40-Meter Beam!  
by AI2IA on July 31, 2014 Mail this to a friend!
All well and good for some hams, but for others perhaps there is a better way. My property is 55 by 200 with the house plunked down in the upper half (the ground slopes slightly)of the lot.

So, I have seventeen antennas. Four yagi antennas, and all the rest are wire antennas. My favorite is a forty meter inverted vee with a big old flag pole as the apex. It runs along the edge of my property line between my lot and my neighbor's lot. I have a four-band vertical wire,too,that gives good service, and an off center fed, and a 180 meter wire dipole bent up like a pretzel that is very effective.

Well, what's my point? My point is that you can take some wire, I like copper clad steel wire, and build yourself a simple, yet effective wire antenna, no fuss, no bother, and low cost, too! You can put up insulated posts at the bends of the wire to make it fit where you please. If it doesn't fit straight, bend it. Don't worry about the radiation pattern.
Let your ears decide if it's good, or needs some adjustment. If you are a patient person and comfortable working with wire, you can have some fun, learn a few odd things about your layout, and come up with your own workable antenna.

This is just a alternate thought.

 
RE: Smaller Backyard, Revised 40-Meter Beam!  
by N4JTE on August 3, 2014 Mail this to a friend!
Okay boring I guess but, but interesting how many folks have responded to my email account for further info, works for me!
N4jte
 
This Antenna typifies the Worst of Ham Radio  
by WA4D on August 4, 2014 Mail this to a friend!
This is the kind of antenna that Hams with no regard for their neighbors or the appearance of their home erect. It is vulgar and representative of the wretched excess many hams exhibit.

The good news is it does not look like an expensive home and may well be rural. No matter, it's a narcissistic display.

These photos should be used in opposition as examples of what Hams will do if the ill advised House Bill #4969 (ridiculously named, "the ham radio parity act") gains any traction.

mike/ wa4d
 
Free to be all you can be.  
by AI2IA on August 4, 2014 Mail this to a friend!
I cannot help but be surprised and somewhat shocked by the comments of WA4D. He would make a perfect subject of a despotic state.

This is the USA here. Yes, in spite of the media propaganda. As our Founding Fathers used to say, and we still say in some legal notices, "BY THE GRACE OF GOD FREE AND INDEPENDENT."

Yes, it is your property. You may put up and use what to others may seem to be the ugliest antenna on earth within the limits of reason and local ordinances. Not limited by the opinions of those who would like to control your life. As a veteran of wartime service, I just love it when I see American citizens exercise their freedom and individuality, especially in the face of neighbors and others who do not mind their own business.

I enjoy the freedom of having and using my antennas, and if I could find one that worked better and fit on my property, even if it was as ugly as sin, I would eagerly put it up and enjoy it.

Here is a great traditional, real American saying for you, "Life, liberty, and property!"
 
RE: Free to be all you can be.  
by N4JTE on August 4, 2014 Mail this to a friend!
Gee, 3 wonderfully engineered, at a grandiose height of 33 feet, that make a truly effective reversible beam in a small backyard will end up, according to wad, as a paradigm of ham irresponsibly, is a ridiculous statement.
Sorry about the 3 syllable words w4ad, don't want to overtax your reading comprehension, but your comments are laughable!
Bob
 
RE: Free to be all you can be.  
by N4JTE on August 4, 2014 Mail this to a friend!
Apologies to whoever w4ad may be, sorry your call is so close to WA4d, I would get as far away as possible from that!!
Bob
 
Smaller Backyard, Revised 40-Meter Beam!  
by JOHNZ on August 5, 2014 Mail this to a friend!
@WA4D

Hello Mike, long time. I still have one of your 1980s vintage QSL cards.

Stick around.

Best to ya!

 
Smaller Backyard, Revised 40-Meter Beam!  
by 2W0ZAE on August 7, 2014 Mail this to a friend!
I really feel sorry for some of you guys across the pond who live with small yards of only plus 48ft.Myself live in a quite small terraced house with just 15ftX15ft back yard and 5 telephone lines crossing my air space so no beams and huge power output.Yet with a very simple made antenna I can work most bands and with a bit of persistence work most that I hear and includes quite a bit of DX even in this low sunspot cycle.
 
Smaller Backyard, Revised 40-Meter Beam!  
by W7ASA on August 7, 2014 Mail this to a friend!
Ah yes - you are quite correct about the relative size of our 'small lots'. However, WE here in the USA are handicapped by other, far worse situations:

1. We do NOT have the excellent Beers/Ales found in your country, and when we can find something acceptable, it's been packed into a tin for the trip over. Not quite the same, I'm certain that you would agree.

2. Our "two weeks" of paid vacation is only 10 day,(2x 5 day weeks) minus all sick time used during the entire year,

3. No kidney pie or

4. Cornish pasties

5. Can't find a decent Vindaloo take-away anywhere!

6. YOU can take EVERY vacation in Europe!


So - at least we've been compensated by having a bit more dirt. (grin)



Cheers and please enjoy a good black beer for me.


73 de Ray
W7ASA ..._ ._

 
RE: Smaller Backyard, Revised 40-Meter Beam!  
by WO9G on August 10, 2014 Mail this to a friend!
Wondering what up with WA4D, I went off looking. I found this at k8es.org/archives/2013_February/Columns/Joe-s_Place/joe-s_place.html

" WA4D was probably the most obnoxious person I ever heard on the air. He used to hang out on 75 meters. Unlike W2OY, he loved phonetics (His own, anyway). He used “Whiskey America Four Dog” most of the time but when he was really on a roll it was “Whisky America Four Democracy”, with heavy emphasis on “democracy.” The guy apparently hated anyone who wasn’t an American. He refused to talk to those outside the country.

One time I heard a station from the Caribbean call him. The “Dawg” surprisingly replied to the guy. However, he took a page out of W2OY’s book and ended his transmission with “How copy Spic?”

One of the FCC’s stated reasons for preserving the Amateur Service is for the promotion of international good will. The Ol’ Dawg was definitely the best example I ever heard of how NOT to do that."

I found a bunch of other stuff too, some with similar experiences and even his own web page and some audio clips. He does seem to be very intelligent but I have to wonder how he gets away with it.
 
Smaller Backyard, Revised 40-Meter Beam!  
by W8LV on August 10, 2014 Mail this to a friend!
Well done, Sir! Much like looking at an RF/S-meter table which shows the little difference between 5 watts and 100, too little attention has been paid to wire arrays as opposed to beams! Wire:no significant wind loading problems, less insertion loss from all of those connectors, no climbing (yes there are crank ups and foldovers I know) no rotor to seize up, or lubricate, less weight. In the art of radio engineering, there are diminishing returns that must be accounted for. I think if one takes a look at performance vs.price, a commercial tower is a tower of diminishing prospects for many of us indeed.

Good to see a man overcome the technical challenges in his particular set of circumstances and then enjoy the satisfaction of the end result.

The other man has a right to his opinion, but in mine, an antenna is a beautiful site to behold...Certainly we can agree to disagree like Gentlemen and let's all toast an achievement in our ranks with a real beer, only a Guinness will do,not that swilly namby pamby lite stuff.

 
RE: Smaller Backyard, Revised 40-Meter Beam!  
by WO9G on August 11, 2014 Mail this to a friend!
Good idea. I'll supply the beer if Bob will come over and build one of those for me in my Barbie and Ken sized back yard. I sure could use an antenna that gets out there like his does.
 
Smaller Backyard, Revised 40-Meter Beam!  
by JOHNZ on August 11, 2014 Mail this to a friend!
@WO9G

Nice flip-flop. In another thread you stated we have the same free speech rights, on & off the air.

You must be new around here. The Dawg has been around for decades, and he is not "getting away with anything."

His speech violates no government regulations.

Dawg is highly opinionated, either listen to him or tune him out. I find him interesting or funny, sometimes offensive. When he is offensive, I simply turn him off or tune him out, can't be any simpler?

Other than like many obese hams, who feed at the public trough on welfare, which they somehow believe they have "earned," and are well known troublemakers, the Dawg has paid his dues.

Dawg completed college, served in Viet Nam, as a company commander, 101st Airborne and later went on to have a successful career in broadcast media. He is a productive member of society. He has more than earned the right to shoot his mouth off once in a while.

And you believe what you read on web sites about the Dawg? The internet is just another tool for old curmudgeon hams to attack each other, a waste of bandwidth. In between welfare checks and on-the-air bickering, hams attack each other on the internet, depending which side you are on in any particular radio war.

 
RE: Smaller Backyard, Revised 40-Meter Beam!  
by WA4D on August 11, 2014 Mail this to a friend!
JOHNZ....

I wanted to thank You for my promotion to Company Commander. Laughs. For the record, I was an enlisted man Spec. 4 in the 101st Abn Division in Vietnam. Infantry Scout Dog handler.

I confess I still get a chuckle at how easily rattled some hams become over a different point of view. The era of "big iron" (or big antennas and big amps) is passe' in 2014. It's all so analog and irrelevant to sophisticated communications. (That said, give me a TS-830 and a plain vanilla 40 meter doublet and I'm in Radio Heaven!)

Cheers,
mike/wa4d
 
RE: Smaller Backyard, Revised 40-Meter Beam!  
by WO9G on August 12, 2014 Mail this to a friend!
Hey JOHNZ, pay attention please. Maybe even go back and read what I said again a couple times. I never once said WA4D should *not* say what he wants to say, I simply said I wondered how he got away with it. I guess for some silly reason when I read the FCC rules I took it to mean that speech like that was off limits. What do I know? I'm new around here so please keep that in mind when you read things I post. Yeah, I do believe he has every right to say what he thinks. Just like I think you have the right to walk up to a Mexican drug smuggler on the border and tell him what you think of him. You are right in doing so but there are some things you can get away with doing only once.

And as for you, WA4D, thank you for serving. I never did but as I got older I wished I had. At least my son did, he spent a year in Afghanistan at FOB Salerno.
 
Smaller Backyard, Revised 40-Meter Beam!  
by JOHNZ on August 12, 2014 Mail this to a friend!
@WO9G

Red herring attempt noted - drug smuggler...blah blah

Only two important points to be made here.

1. Dawg type speech does not violate any government rules & regs.

2. Elderly crotchity hams need to locate the big knob on their rice box, find another hobby, lighten up, or operate A1A exclusively.



 
RE: Smaller Backyard, Revised 40-Meter Beam!  
by K8KAS on August 14, 2014 Mail this to a friend!
Poor dog Mike, did you check his paws for hi SWR??
 
off topic  
by WA4D on August 16, 2014 Mail this to a friend!
@K8KAS.... Laughs. No SWR checks. BUT.... I spent months in the Jungle of I Corps (Northern part of S. Vietnam). And my dog "Argo" walked first down the trail. In the heavy rains of the Monsoon season, the trails in the jungle were thick with leaches. And leaches attach to anywhere there is living tissue (i.e. blood). GI's wore "Leach Straps" tight around your leg just below the knee so leaches couldn't get any higher than your calves. Every few hours in the rainy season, I'd pull up each of his paws and check for leaches. Often there were several. The US Army's idea of "Mosquito repellent" was basically gasoline! Laughs. It came in little plastic squirt bottles. Squirt some of that stuff on the leaches between his Paws and they came right off! --- Oh and I still have my "leach straps" to this day.

Cheers
 
RE: off topic  
by W4VR on August 31, 2014 Mail this to a friend!
Bob: good article. That installation would make any backyard look just spectacular. with all that wire, your bird kill must be astronomical though. Ron
 
Smaller Backyard, Revised 40-Meter Beam!  
by KW8C on September 10, 2014 Mail this to a friend!
OK Bob, you have my attention. I like your idea and I think I have the room for this antenna. At present I am using a full wave loop cut for 80 fed with latter line. It's only up 25 feet but works very well. I want something with some directivity and I need a project to work on. I will give this a try and if it's OK with you I will let you know how things turn out.
Nice article.
Thanks,
Don
 
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