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As I made antennas ( . ...)

I shall try to tell in detail to you about how I made the antennas (20/15/10) as carried out various elements of a design, in how many their cost has costed and, at last, as they work.

For the beginning there is some "water". (At once I am sorry for so big story. It would be desirable to tell all in detail and to share the impressions).

The idea of installation of the effective directed antennas has arisen at me in the spring of 2003 after the several interesting moments.

My friend Slava, UA3AJU leaved on the permanent residence for Mexico and has presented me rotary the device and 4 elements YAGI on 10 meter range. In 2 days I of her has established, has adjusted on device MFJ-259 and the beginnings the experiments in comparison of "Vertical" (5/8 on 27 MHz, reconstructed on 28.150) and YAGI. From the first connections it became clear, that YAGI works better many times over! I looked in DX-cluster info, listened on the probe while turned YAGI, and then listened on YAGI... to Effect was amazing! I have understood, that earlier I did not hear more than 40% DX!

There was expedition 1, I waited for them in CW (I prefer this kind of modulation more, than the others) on 10 meters band, but and not has waited. Suddenly I see in DX-Cluster info about K1B on 10 meters band in SSB! I proceed on frequency on which should be 1, I listen - silence. I turn YAGI on them and I hear without "points", but it is completely legible 59! K1B, up 5. I put split 5 above and I name 2 times "RW3AFY", in the answer in Russian RW3AFY, hello, 59! (it was Igor Buklan, RA3AUU) and I spend with him QSO. It was the first "powerful" DX on the new antenna.

After that I have understood, that without the good directed antennas to me there is simply nothing to make on air since for 4 years of work on HF was is fulfilled 300 territories, and the others I could not contact on 100 Watt, dipoles, inverters and verticals...

Now about a choice of antennas.

There were only 2 variants - YAGI or squares. Besides variants of purchase of antennas (the BREEZE, R-QUAD) and independent were studied and counted manufacturing.

From the BREEZE I have refused practically at once since has read about them the set of negative clauses in an Internet (here one of them) and Expensive their antennas, on R-QUAD too did not suffice money, therefore has decided to make antennas by the hands, using some technologies of that and another firms (has seen enough pictures of their antennas in an Internet)! For example from the Breeze- rivet an element, but in part, from R-QUAD a way of extension boom, etc.

Why all the same YAGI?

The matter is that YAGI, as against squares less bulky Also have narrower corner of radiation in horizontal, accordingly YAGI it is more interesting to rotate. Besides, having communicated to people, having listened to different opinions, has come to conclusion, that both variants of antennas are practically identical under characteristics... Somewhere YAGI wins, somewhere squares... Proceeding from this I have chosen variant YAGI since them it is easier to make the hands.

I asked a question From what to begin?

Before I already compared various variants YAGI their dimensions and an arrangement on masts. It would be desirable to make some effective antennas and to arrange them on one mast (has besides seen enough in an Internet as radio fans using one mast establish antennas in 2 floors). Has stopped on a variant 4 elements on 20 meters band on separate boom, 4 on 15 meters and 5 on 10 meters on one boom (recognizing that 15 meters band on 10 meters band special mutual influence not test). Besides I can compare 4 elements on 10 meters band about 5-th!

Made of such choice it was set not less by pressing question Where to take such mast on which all this without problems would stand?. The answer has been found very quickly mast - UNZHA! But where to take 700-1200$? (for this their money radio fans) sell. Besides to me has carried! Appeared, that my chief the former commander a shelf of air defence. I have addressed to him and he with pleasure has decided to help me. In a week I already went in Moscow suburbs to look a little some variants UNZHA, has picked up most "good" (1964 year) also has agreed upon the price - 200$ for the lift, 13 sections and 4 two-drum-type coils with a steel cable! And as for 35$ to me in a makeweight gave one more lift and basic plate! I was delighted! Delivery in Moscow on automobile cost 25$. About some features of operation mast I shall write later...

And so, the mast at me was, now it was necessary to count the sizes of antennas to choose a material and diameters of pipes and to develop various units fastenings.

Since I not so understood in programm of MMANA, have decided to address to one more friend Dmitry, UA3AVR (this person writes very interesting clause concerning simple and practical antennas). Having listened to my "inquiries" about the account of the future antennas and their parameters (the maximal suppression and the maximal amplification). Dmitry has decided to help me with calculations!

It has been counted 2 YAGI on 20 meters band... one on 7 meters boom, the second on 12 meters... The difference in suppression and amplification at 12 meters in comparison with 7 meters is little bit higher, accordingly and dimensions it is more, but the sizes of me did not frighten also I has chosen her.

With calculations 15/10 on one boom was much difficulties, but Dmitry them has overcome (for what to him MANY THANKS) and has given out to me very good variant of the two-band aerial on boom in the length of 10 m. Moreover also has calculated for all antennas the sizes of the Omega-coordination and parameters of capacities!

The File with calculations of antennas in format .

I want to tell at once about cost of all materials, can and there is nothing will read further.

Pipes and a strip including cost of her cutting - 400$, account materials (tension bolts, collars for a steel cable, a rivet, automobile collars, long bolts, a steel cable, etc.) - about 100$.

A choice of materials for manufacturing.

In my opinion, the biggest company in Moscow trading aluminium is the company ALROS, on their site I and have gone... At them are sold pipes from material AD31 in condition T1 (tempered also it is artificial old) I have decided to make antennas of them. (After installation of antennas were strong Wind, but, "Thank God", pipes will not bend!)

And so I have chosen:

  1. booms from a pipe 504,0 mm, inserts inside booms for connections of their parts from a pipe 424,0 mm (pipes have densely come each other without any problems).
  2. Elements YAGI on 10 meters from pipes 202,0 mm and 161,0 mm (pipes as have densely come each other); elements YAGI on 15 meters from pipes 252,0 mm and 202,0 mm; Elements YAGI on 20 meters from pipes 252,0 mm, 202,0 mm, 161,0 mm.
  3. Vertical racks on boom, for "support" of elements YAGI on 20 meters practically in a horizontal condition from a pipe 202,0 mm.
  4. Plates for fastening elements to booms from a strip 808,0 mm from the same AD31T1.
  5. Supports, extensions booms are executed: at 15/10 from the steel steel cable in diameter of 5 mm, at YAGI on 20 meters, in avoidance influences on 15/10 from a kevlar cable (aramide) got in firm R-QUAD.
  6. U-shaped collars for fastening elements to plates and, accordingly, plates to booms from long bolts with groove 6 cut on all length (them it is a lot of in the building markets, are used basically at construction of ventilating pipes). Photo
  7. For a tension of cables booms are used long bolts 8. Photo
  8. For fastening cables the Finnish clips are used for steel cable. Photo
  9. various account materials also are used, about which I shall tell during the description of a technique of manufacturing.

Pipes and strips are sold any length multiple 6 meters. It is less 6 meters to buy it were impossible... Pipes are cut on 3 meters, a part strips (3 meters) on 14 pieces on 200 mm + scraps (the second part of a strip lays on balcony also waits from me for new ideas on manufacturing antennas).

The general length of pipes has been counted recognizing that:

  1. Pipes from which the element, for reliable fastening will consist, should enter each other on 150 mm;
  2. Inserts booms in the length on 600 mm (300 mm in one piece boom, 300 in another), general length booms 22,5 meters (has bought, accordingly 24 meters);
  3. Vertical racks for support of elements in height on 300 mm.

I first from what began manufacturing having in stock all materials - has bent from long bolts 6 U-shaped collars for fastenings of elements and plates to booms. (Collars for the diameter of 20 mm - 10 + stock 2 piece, on diameter 25 mm - 16 + a stock 2 piece, on diameter 50 mm - 26 + a stock 4 pieces). For fastening antennas to a mast has bent U-shaped collars on diameter 50 mm from long bolts 8 (16 piece + 2 stock). Bolts bent using tube the necessary diameter. Tools: tubes, a hammer, an anvil, vice. The length bolts is calculated under the formula suggested by Nikolay, UA9XBI in to clause Five-element YAGI on a range of 20 meters.

L = 1,57 * (D+d) + D + 2*M + 40

Where:

L - Necessary length long bolt
D - Diameter of a pipe, which fixes step-ladder (U-shaped collar)
d - Diameter bolt from which the step-ladder
is made
M - thickness of a detail to which the pipe (a plate of fastening of an element to boom)
fastens
40 - a stock for nuts of fastening.

The second - has marked and has drilled on the machine tool of a plate for fastenings of elements to booms.

Distance between apertures for fastening U-shaped collar equally to diameter of a pipe, which fixes a collar, plus diameter bolt from by which the collar is made.

Now it was necessary to measure all pipes (their length was on some mm is more than 3 meters, but in any way it is less) that is correct them to use, with a minimum of scraps. Pipes has measured, has signed on them all values, has noted the middle, has estimated as them rationally to use and has started to work.

Here the primary goal was to make a reliable design with Minimum of through apertures.

On the basis of one element:

On distance of 125 mm from the end of a pipe in her it is bored through aperture through one wall (the PIPE is not DRILLED THROUGH, ONE is DRILLED ONLY WALL) diameter of an aperture is equal to diameter of a rivet with which help are fastened pipes the in each other. (Rivets I have chosen 48 mm). On distance of 20 mm from the end pipes perpendicularly axes previous one more aperture is bored through, only already through both walls of a pipe. Further in an end face of a pipe (an end face with the parties of apertures) are sawn through grooves necessary for a clip automobile collar of two pipes inserted each other. Both walls of a pipe are sawn through. Length of a groove - 20 mm, the width has spent on drink it is equaled to thickness 2 cloths, about 3 mm. In the end has spent on groove the aperture should be necessarily drilled (it at us is already drilled, up to him and we saw), it protects a pipe from crack on an axis has spent on groove at change of an ambient temperature. Due to such a prosaw, at a tightening of a collar, one pipe densely fits another and reliably clamps her in itself.

Each element YAGI on 20 meters is made from 5 pipes. One 25 mm diameter (in the center) in her on end faces are inserted pipes in diameter of 20 mm, and into them, in the turn 16 millimetric. Pipes enter each other on 150 mm.

Accordingly prosaws are made from both end faces of 25-th pipe, with one end face at each of 20-th. Apertures for fastening by rivets are drilled with Both parties in 25-th pipe, from both parties of pipes of 20 mm and from one of the parties in 16 millimetric pipes. The final length of an element is adjusted extreme, 16 millimetric pipes.

Each element YAGI on 15 meters is made of 3 pipes. One 25 mm (in the center) in her on end faces pipes in diameter of 20 mm are inserted. A technique drillings also are sharp the same as at YAGI on 20 meters. Pipes enter each other on 150 mm. The final length of an element is adjusted extreme, 20 millimetric pipes.

Each element YAGI on 10 meters is made of 3 pipes. One 20 mm (in the center) in her on end faces pipes in diameter of 16 mm are inserted. A technique drillings also are sharp the same as at YAGI on 20 meters and YAGI on 15 meters. Pipes enter the friend in the friend on 150 mm. The final length of an element is adjusted extreme, 16 millimetric pipes.

After manufacturing and marking (all is necessarily sign a marker directly on pipes, and that at me was some nuances :) ) elements I have engaged in manufacturing booms. Boom it is made of a pipe in diameter 504 mm. For connection three-meter pieces of a pipe inserts from a pipe 424 by length on 600 mm are used. Boom on YAGI on 20 meters it is carried out from 4 pieces on 3 meter and a slice in length of 700 mm (general length boom 12,5 meters + a stock on fastening of extreme elements - 200 mm). Boom 10/15 it is carried out from 3 pieces on 3 meter and a slice in length 1200 mm (general length boom 10 meters + a stock on fastening of extreme elements - 200 mm). To fasten pipes booms and inserts it is possible as well as elements, but on 2 rivets on half of insert, i.e. 4 rivets on one place of a joint 2 three-meter pieces booms. Rivets 4,815 mm. in a consequence it was found out, that this fastening not especially reliable also should be altered. I have left on 2 rivets on one place of a joint of 2 three-meter pieces booms and instead of 2 more rivets has put 2 through long bolts 6.

The following stage - to find out, whether it is possible to establish elements YAGI on 20 meters without kevlar supporting ropes? Elements were taught from 9,6 up to 11 m in the length. Has carried out experiment, having collected an element has put his central part on towering surface simulating boom also began to measure has sagged the ends. Has sagged appeared about 300 mm from a horizontal plane. Has then applied on the end of an element loading, kg 2-3 (ravens or icings) also has understood weight, that without supports from kevlar all will break. Proceeding from this, it was necessary to think up, from what to make vertical racks above elements, as them to fix and how to execute units of fastening of ropes to elements. Since remained scraps of a pipe 202 the mm from her also has decided to make racks. Racks have height 300 mm, in the bottom part rivet to duralumin corner which is attached to a plate fastenings of an element to boom one of collars fastening a pipe of an element to this plate. In the top part of the rack 2 through apertures in one plane are drilled, in which are inserted bolts with a groove, bent on the one hand as a loop. (Accordingly loops are directed to the different parties). Thus it has turned out unit by means of which it was possible to pull independently from each other left and right parts of an element. Fastening kevlar to an element is executed by the following in the image: For performance of this unit are used small carbines (as on backpacks were) and auto-collars earlier. Carbine it is dressed on on an auto-collar, a collar it is dressed on on a pipe of an element and it is strongly strapped (it takes the form of a drop, and carbine presses through small hole on a wall of a pipe of an element, as does not allow him to move in the direction of boom). The rope fastens to an element on distance 1/3 half of element. The place of fastening is counted, accordingly from the end element. I.e. if the element has length of 11 m, its half of 5,5 m, a rope fastens on distance of 1,8 m (5,5/3) from the end of an element.

The following stage - extension booms. (It I completely has copied at guys from R-QUAD. Big thanks for interesting engineering decisions and qualitative photos). Unit fastenings of cables to pipes booms it is executed from long bolts 8 and nuts as a ring (the scientific name of the Eye - nut) Photo. On booms YAGI on 20 meters such units 4 (2 on one part boom, 2 on another), on boom 10/15 - 2.

The coordination.

As the coordination for all antennas it was used The Omega-coordination. The Omega-coordination is applied owing to small entrance resistance of antennas.

Sizes Omega:

  1. YAGI on 20 meters - length of a pipe of the coordination of 1 m, diameter 20 mm, the condenser parallel to a loop - 120 pf., consecutive to a cable 260 pf., at length in 1.5 m. the parallel condenser decreases up to 70 pf., consecutive to a cable
    approximately the same. I.e. condensers can be taken type 12-450 pf.
  2. YAGI 15/10 - lengths of pipes of the coordination on 1 m., for 15-th diameter 20 mm, for 10-th diameter 16 mm.; rough capacities of adjustment in parallels 40 pf., it is consecutive 80-100 pf.).

I used constant capacities designed Dmitry, UA3AVR (they are described above).

To adjust it was necessary only YAGI on 10 meters. On YAGI on 10 meters I advise to put variable capacities, to adjust, and then to solder in constants.

Since on a roof of my house especially you will not be developped, assembly antennas I carried out as follows:

Has preliminary fixed on a vertical pipe (hand-rail) on lift mast a steel plate, to which 4 U-shaped collars 8 should fasten boom 15/10. Has collected boom 15/10 and has fixed to her steel cables. Has lifted her for the middle and has got on a step-ladder. Has got up to places of fastening boom, has applied her on a plate and has fixed 4 collars. Has fixed tension bolts and has pulled cables supporting boom. Further began to collect elements. Fixed to the middle of elements of a plate, rivet tubes of elements the friend in friend also pulled together automobile collars. Having collected one element I at once fixed it on a regular place on boom, preliminary measured and marked by a marker. Such method of gathering of the antenna (to collect on 1 element) has been chosen me because I was afraid to not have time to collect all antenna (I collected its one) up to darkness, and to leave on a roof the collected elements was afraid, aluminium all the same!

In 3 hours all elements have been fixed precisely in one planes and it is strictly perpendicular boom. Then having turned off collars of fastening boom to a mast, has moved all aerial on 30 sm forward, having found out, thus, the centre of gravity of a design. The most important to not forget about agreeing an element and coaxial cables, moreover and hermetic sealing all.

Further the assistant in which role I has acted was necessary for me father. We have hung up the block on a top of a vertical pipe of fastening of antennas, having thrown through it a kapron rope. To a place where there is a centre of gravity of the aerial have fixed one end of a rope, and for the second pulled the aerial upwards, up to the block. I has climbed on a pipe and having become attached an assembly belt has fixed boom YAGI, and then and tension bolts by which she is stretched. The first part of construction has been executed.

Next day in the same way we have collected YAGI on 20 meters and have fixed her on a regular place under 15/10. Photo

Gaugings with the help of device MFJ-259 further were coming, which have very much pleased me. 20 meters band was in a resonance on 14.120, 15 meters band on 21.100, 10 meters band on 28.250. After rise of antennas resonant frequencies have crept away upwards on 20-30 , i.e. 14.150, 21.123 and 28.270. It quite arranged me, all the rest completes an automatic antenna tuner.

Well and then rise mast and pleasure by loud signals stations! Photo

I wish success in construction of antennas!


Last Date Modified: 11 november 2004
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