Efficient VHF antennas at 430 MHz directional

Answering Vladimir's question regarding the antennas in the guest book, I, unfortunately, can only advise you to choose. Everything good was invented before me.... :-) Here is an option that corresponds to the given definition: very simple and effective.
http://www.cqham.ru/forum/showthread.php?t=7925. If we install this on a rotary bearing on the balcony (or in another accessible place where the “control lever” can reach), we get a really effective antenna system.
Here is a whole archive of antennas from RZ9CJ http://qrz-e.ru/forum/30-119-1 I could, of course, let you download it from my website, but out of respect for the author, a link to the forum, where he himself is put it Choose any design from this archive, it will work. You just need to follow the author's instructions exactly. Don't be upset if it doesn't work out right away. Try again. But we all know that free cheese in a mousetrap, and simple and effective is more of a fantasy. In any case, you will have to make a compromise: either simple or effective. In shares. These (suggested above) antennas are somewhat heavier than “hand drive” antennas.

The thing is good, it has proven itself well, but when making communications (or when trying to make communications), we definitely felt that even if we hold such an antenna exactly in the direction of the satellite and do not move at all, then fading, or, as the professionals say, fading, will seriously harm us connection quality. And if the correspondent is not very audible, if, for example, we are working not through FM ECHO (AO-51), but through the transponder of a nearby flying AO-7 or FO-29, then the communication can turn into a game of “Guess the call sign.” The fact is that satellites rotate.

Unpredictable. Accordingly, any antenna, even non-directional, has radiation minimums. Plus, VHF and even more so SHF signals are characterized, in addition to the usual fading, by polarization rotations. Well, I hope there is no need to explain much about polarization - electric and magnetic waves prependicular to each other are also oriented relative to the earth. For example, if electric waves are perpendicular to the earth, and magnetic waves are correspondingly parallel to it, then the polarization is vertical and vice versa. The best option is when both the transmitting and receiving antennas have the same polarization (may the great experts forgive me, I am writing for amateurs), for example, on both sides GP, or GP and squares with vertical polarization, or on both sides Yagi elements of which are perpendicular to the Earth, etc. .d. But even in these cases, depending on the distance and the media through which the radio waves pass (the state of the Ionosphere, such as solar wind, the atmosphere, such as rain or heavy clouds), the polarization rotates relative to the earth and relative to us standing on it.

In conditions of radio exchange with low-energy signals, in short, so weak that under the influence of the factors described above, at times they disappear altogether, if we manage to make an antenna that is insensitive to changes in polarization and has circular polarization, then we will have advantages over radio amateurs who do not have such a tricky antenna. The physical meaning is that in the same place in space there are two identical antennas, rotated 90 degrees relative to each other - one with vertical polarization, the other with horizontal polarization, but this depends on how we hold the antenna. Hee. The only difficulty is that you need to rotate the phase of the emitted (or received) signal by 90 degrees. And, of course, don’t forget that we need to get everything in one bottle - i.e. connector Looking ahead, I will say that it is better to have two separate antennas, and in the apartment, if necessary, combine them onto one cable using a duplexer. This is if you do not have a serious transceiver with two independent bands, but an ordinary hand-held “walking gun”. But sooner or later you will appreciate independent antennas. :-) Without further ado, I bring to your attention two manually driven antennas at 144 and 430 MHz, which, when assembled on one traverse, will form a structure resembling Christmas tree. Many people probably recognize the design of transformers. Yes, I’m not hiding it - of course it’s I6IBE. Instead of a connector, you can connect a 50-ohm cable of any length.

In Figure 1 you can see that after the connector there is a coaxial transformer made of quarter-wave sections, which simply matches the cable resistance to the resistance of two half-wave dipole vibrators connected in parallel (the figure shows that there are also reflectors), i.e. transformer 1:2, or rather 2:1. Next, one antenna is powered by a quarter-wave segment, and the second by a half-wave segment, which results in a rotation of the phase of the emitted (received) signal by 90 degrees. That's all. That is, there is no gain in gain compared to a two-element Yaga, but now we don’t care how the polarization of the signal “spins.” We don't feel it. In our space version, this is a huge plus. The second picture shows the same thing with the dimensions for 435 MHz. It is better to use antennas separately (you can use one traverse, but at a distance from one another. Personally, I think that two cables are an advantage, although you can use a duplexer. After everything you have read and understood, a feeling of deja vu arises - we have already gone through all this on HF: do you want to have connection - you have to try, but the pleasure from the final result is worth it.

So let's move on to the practical part. We find a wooden beam with a side of 30-40 mm and a length of at least 220 mm, pre-impregnate it several times with some varnish or composition that protects it from moisture and let it dry thoroughly. This is very important - we need the best possible dielectric :-) Next, we prepare the contact pads into which we screw the elements themselves into threads, and the ends of the cables into self-tapping screws, which are also fasteners. These pads must be made of the same material as the elements themselves, and their thickness is critical: the ends of the elements, especially in the 144 MHz range, must be screwed into them with a sufficient margin of safety. The structure can be strengthened with galvanized locknuts. Transformers-phase shifters are attracted to the traverse with plastic clamps or simply electrical tape. The distance between the two antennas should be at least 50 cm. More is better. Of course, if the antennas are made completely independent, then we skip this step as unnecessary. But then you will have to turn them synchronously. But my personal experience suggests the following. Even after making such complex antennas, you should not count on communication over long distances: after all, these are only 2 elements. Thus, we assume that communication will most likely occur when the satellite flies over us. Those. at the zenith. Is it worth turning the antennas then?

The answer is obvious. Therefore, the antennas are assembled on one traverse and installed vertically. It turns out to be a kind of “Christmas tree” that does not need to be rotated. The lobe of the radiation pattern of two-element antennas is not narrower than 70 degrees in both planes, so we will get a satisfactory “firing” zone. The gain of such an antenna will not differ from a conventional 2-element yagi, but the reception (gain) in circular polarization will be very much (and pleasantly) different from the standard version. This “herringbone” can be simply raised above the ground or roof if you choose not 2.2 meters of timber, but as much as we can get. Or simply extend it, turning the lower part of the boom into a mast. In a word, the antenna is a confirmation of the proverb “need for invention is cunning.” Or, as people say, “candy made from feces.” :-) It is quite obvious that this lightweight antenna can be rotated in this configuration and split into two separate antennas. Just add a crossbar along the edges of which two separate antennas will be installed. If all this seems too complicated to you, use the links at the beginning of the article. It will still be better than GP. The choice is yours.

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A couple of posts ago I joked that the Boeing 777 really loves the Icom 7800 :-) Instead of a cockpit, they have 3 Icom7600 and 3 IC-7800 in the cockpit. But it turns out that Icom loves NASA more than anyone. Space Shuttle Endeavor: here Icoms should be counted, if not in dozens, then certainly not in pieces..... :-)

GoshaCom trial

Or the rustic RigExpert. I use a Kenwood TS2000 on my VHF. And I needed a CAT device and controls for it, but my Unicom Dual had to stay in place, on the Icom 7600. And I asked a friend UR5RFF to borrow his RigExpert Tiny TI A worthy toy, there are as many as 4 COM port and two audio cords for connecting not to the microphone, but to ACC2. Only the price is also decent - under 2 and a half hryvnia. With cords it’s even more expensive. It works great, you don’t need to solder anything, just pay some money. And here's the bummer. I have no money. True, no, not because he’s greedy. Those who follow know that they just came from the operating table, and medicine is even more expensive than amateur radio :-) I sold everything I bought quickly, but I still owe the same amount. In a word, I want to play around in FT8 on VHF, and control ExtFSK in MMTTY, and N1MM should work on both transceivers. In short, I began to think and wonder where I could get the control.

Telegraph fans

Well, not for the fans either. Poking around on the Internet I accidentally found a gallery of a wide variety of ways to manipulate a telegraph transmitter. There are 81 of them so far. Not all of them are original, of course, but there are a couple of interesting ones. The full gallery of ideas can be viewed on the OH6DC website. Everyone is working. Each method is illustrated with a corresponding video :-)

SAT	Availability of transpon	Power	CW beacon	Range		signal strength	Is there software	Ease of setup	Data decryption	bonus program	Total score
AO-7	3	1	0	5	5	4	0	0	0	0	18
Delfi C3	0	3	1	4	2	4	4	1	4	1	24
Funcube-1	2	3	1	4	2	4	4	2	4	2	28
Ukube-1	2	3	1	4	2	4	4	2	4	2	28
PolyItan	0	4	0	3	3	0	2	0	4	2	18
FO-29 Fuji-Oscar	2	5	1	5	5	3	0	0	0	0	21
SO-50 SaudiSat	1	5	0	5	5	4	0	0	0	0	20
Masat-1	0	5	1	5	2	3	3	2	4	4	29
ISS	1	5	0	4	4	4	0	0	0	3	21
Eagle-2	0	1	1	1	0	0	0	0	1	0	4
*Availability of transponder	In points: 0 - no; 1 - one frequency UP/DOWN AX25 or FM; 2 - 100 kHz band; 3 - 100 kHz bands in more than two bands
*Transmitter power	In points; 0 -<10 mW; 1 - 100 mW; 2 - 200 mW; 3 - 300 mW; 4 - 500mW4 5 - >500 mW
* Presence of a beacon	In points: 0 - no; 1 - yes.
*Range	In terms of accessibility for radio amateurs: 1 - 5.6 GHz; 2 - 1.2 GHz; 3 - 435 MHz; 4 - 145 MHz; 5 - 29 MHz.
* Modulation	In points according to the degree of decoding accessibility: 0 - special; 1- GMSK; 2 - BPSK; 3 - FSK; 4-AFSK; 5 - CW/SSB/FM;
*Duty duty	The points are inversely proportional to the time: 0 - more than 2 minutes; 1 - more than 1 minute; 2 - more than 30 seconds; 3 - more than 10 seconds; 4 - continuously
*Software	In points: 0 - absent; 1 - in the form of a “parameter-value” table; 2 - “digit-parameter” converter; 3 - combined with the setting unit; 4 - setting-decoder - AFC
*Easy to set up	In points: 0 - absent; 1 - own indicator; 2 - own automatic
*Data presentation	In points: 0 - absent; 1 - available in the form of a table of values; 2 - automatic in the form of “parameter-value”; 4 - automatic with table construction
*Bonus program	In points: 0 - absent4; 1 - mention on the site; 2 - QSL card; 3 - special certificate; 4 - on the website and QSL (certificate)

The granddaughter left - the exotic came down

After a lunchtime nap, my daughter took home the joy of my eyes - her 4-year-old granddaughter Alice. I didn’t grieve for long - I just had to turn on the transceiver and I felt better :-) And then the exotics fell on the fiftine. And everyone answers. And it sounds good. It has relieved significantly. :-) HL2LDV XU7AEX YD1MRI 4W/N1YC BD8SG and the main consolation - Saipan KH0/K6WP appeared in the log. Although Timor was heard better.
AUDIO Timor Leste 4W/N1YC fiftin CW

AUDIO KH0/K6WP fiftin CWAfter 10 minutes everything is the same and the same, but already at twenty.....

Forecast for the end of May

The state of solar activity is not encouraging at all: there are almost no changes. If the solar flux is still changing somehow, then the number of flares at a stable minimum is 0:-(But nevertheless, the earth and water have already warmed up and some positive dynamics can be traced. But this applies primarily to the HF ranges. At ranges below 10 MHz the penetration will remain at the level of the beginning of the month: stable but modest. For fans of the top bands, this is not news, and we are not particularly spoiled, so we will be happy with the passage on the HF bands.

The same is not very strong, but stable transmission will be in the ranges from 10 to 24 MHz. On the top ten, the passing zones will be highly fragmented, but there will be many of them. I recommend not turning off the receivers of this range (or CB radio).

But in the range from 80 to 15 meters, the passage will be around the clock. Isn’t this what we all miss: I turned on the transceiver, and there was someone there :-)

On the VHF, the change in the average daily temperature (and humidity) had a better effect: almost the entire twilight time was confidently tropical. In the morning, our city APRS (packetradio) was easily read in Kyiv (180 km) and vice versa.

Dmitry RV9CX, proposed an excellent antenna, manufactured simply and with a minimum of parts

The X-200 is a dual-band (144/430) collinear antenna with an omnidirectional pattern and high gain.

The first such antenna was made in the late 90s and even still works.

The antenna is made entirely (including all coils) of solid copper wire with a diameter of 2 mm without intermediate soldering. All reels are frameless. Capacitor C1 is made from a piece of SAT-703 coaxial cable 2 cm long - it is for the system to operate on the 70 cm range. Capacitor C2 is an air capacitor, a tuning capacitor - we use it to tune the antenna.

Well, everything is clear with the electrical part - let's move on to the technical implementation.

The power load was carried by the wooden handle of a shovel (only slightly more powerful than what is sold in stores).

A fiberglass fishing rod was attached to it with electrical tape (now the issue can be solved more beautifully, of course) lightly (so as not to pinch), inside which everything that was wound with back-breaking labor was placed, i.e. the antenna itself, lined with anti-bounce foam pads with all coils (except L4 and capacitors).

Two through holes were drilled in the handle 5 cm below the L4 coil, perpendicularly, but with a height difference of 5 mm, for future counterweights. Counterweights were inserted and soldered. Their fastening can be seen schematically below

Counterweight mounting diagram (top view)

Now setup.

First of all, you need to configure the parallel circuit C1/L4 to the average frequency of the 70cm range - it is this that allows you to power the entire structure at these frequencies. The location of the tap in L4 determines the transformation ratio. Well, if there is nothing to check, then leave it as it is. I have never checked this either, because... at that time there was nothing.

I made adjustments only according to the readings of the SWR meter right in the room, placing the antenna horizontally. High ceilings made this possible. The adjustment is made by rotating rotor C2. It should be noted that if it is not possible to “immediately” obtain the necessary indicators by agreement simultaneously in both ranges, you need to select a tap from the L4 coil.

As a result, I got very good results according to the agreement:

145MHz - SWR=1.03

435MHz - SWR=1.02

After adjustment, an empty Sprite bottle was placed on top of the matching unit, which protected all open parts from moisture. After 10 years, this bottle lost its green color.

Practical work on air showed the full functionality of the system, incl. and in comparison with branded products. In connection with this, this design was repeated several times. Moreover, its repeatability coefficient is very high with the specified manufacturing technology.

I love mountains. I love them on their own and love working with them on VHF. And for successful operation you need good antennas. But an antenna for working from a high mountain must first of all be light . After all, you don’t really want to carry a structure weighing, say, 5-6 kg to a height of 1400-1800 meters - in addition to the antenna, you have to carry a transceiver, batteries and other tourist equipment with you. In addition, you often even have to carry water up with you - it is rare in the mountains.

And so, having clearly imagined what exactly I wanted (I needed a light yaga with power supply via one cable at 144 and 430 MHz, I decided to make a separate antenna at 1200 MHz), I began my search.

The first thing I discovered was that many companies had been producing the models I needed for a long time. For example, a well-known American company Cushcraft produces 2 such antennas - A270-6S And A270-10S:

At first glance, these are good antennas, even according to the description they seem to be made of stainless steel. But both have a surprisingly stupid type of power supply (and this is generally typical for most things from the American continent): 2 active elements of these antennas are stupidly powered through a splitter. Yes, yes, not through a duplexer, but exactly that way - through a splitter. Those. For their normal operation, these antennas will have to be modified.

In addition, there is also an irrational use of the traverse - in both one and the other design, the 430 MHz elements do not occupy its entire length. And this, from my point of view, is a serious drawback.

In general, despite the tasty price ($110 and $150 in the USA for the A270-6S and A270-10S, respectively), Cushcraft gets 2 big minuses and I lose the desire to buy antennas made by them.

From a Japanese company Comet There are also 2 models: CYA2375 And CYA25711. Good antennas, but the price... Not just sky-high, but generally astronomical! Something like 12 and 18 thousand rubles “here” for CYA2375 and CYA25711, respectively. All that remains is to look at the pictures, lick your lips and forget about them. Here are CYA2375 and CYA25711:

So, who else do we have left? Yeah, he stayed with us Diamond. On this moment produces only one model - A1430S7:

Inexpensive good antenna - about 6500 rubles. "here" is new in the box, and the fill factor of the traverse is good. But there are few elements, and accordingly, it does not shine with reinforcement. I thought and thought and decided not to take it.

Here knowledgeable people suggested another antenna to me - Maspro WH59SK. 5 elements at 144 and 6 at 430 MHz. Gain at 144 MHz is approximately 5 Dbd, at 430 MHz approximately 8 Dbd, length 1.35 m, weight 1 kg, mast diameter 22-32 mm, input maximum 50 Watt (in FM). Compact, foldable, lightweight. Well, this antenna is good for everyone. But there were also 2 problems: 1) It is almost impossible to buy it new, because it has been out of production for about 5 years. 2) If you buy it, it will only be used, and used ones begin to show their main drawback - due to oxides, the contact in the rivets worsens and the SWR increases, the gain and diagram deteriorate.

Here is a photo of the Maspro WH59SK antenna:

In general, I searched and searched for a more or less new WH59 - and did not find it. And I decided to make a 2-band yagi myself. Which I never regretted later.

A short search on the Internet led me to Sergei, RZ9CJ. What was captivating was that there were many designs, for different diameters of available wires and traverses, for different ranges, with different reinforcements. Calculated in Maman and tested by dozens of people in practice. Well, they couldn’t help but work!

From all this wealth I chose this design - “5 + 7 - 5mm”, since 5 mm aluminum wire quite tough and I had it:

But, as always, there were a few engineering puzzles to solve first. For example, what to make a traverse from? How to make the antenna elements sit firmly on the traverse, not wobble from side to side and not move back and forth along it? And at the same time, the elements must be quick-detachable (or foldable). If you make them foldable, how can you ensure good electrical contact in them? Hmmm, this is not an easy task...

I felt a little depressed. I didn’t sleep for 2 or 3 nights, I thought a lot :) Finally I came to the conclusion that thinking a lot is harmful, it hurts the brain. And that you just need to go through plumbing stores, maybe you’ll come across something. And it came across:

I found such a wonderful bracket for attaching meta-floor pipes to the wall in one of the countless stalls on the Bagration ring (I think Vladivostok residents don’t need to explain where it is and what it is :)). And the price is just a song! Only 9 (nine) rubles apiece!

I checked how these brackets fit on the 20 mm traverse pipe - it turned out that they fit just fine. It is difficult to remove by hand; you have to forcefully tilt this bracket along the pipe to tear it off. Having taken a couple of dozen, I started thinking about the type of traverse. The choice was from 2 pipe options - meta-floor or polypropylene. I chose the second one - it seemed to me a little lighter and a little stronger in bending than the meta-gender one. In addition, the polypropylene pipe had a straight red line along it, as if someone had specially drawn it to make it easier for me to fasten the elements :)

I cut off the “antennae” that I didn’t need on the brackets and drilled 5 mm holes for the antenna elements. Due to the fact that the plastic of the bracket plays back a little, the hole turns out to be slightly smaller - about 4.8...4.9 mm and the element is held in it very firmly. In addition, I inserted the elements “hot” - before such an operation, I warmed up both the bracket and the element with a regular hair dryer. After cooling, pulling the element out of the bracket is a very difficult task.

Then everything is quite simple: so that the brackets with the elements do not move back and forth and do not rotate around the traverse, use stainless steel self-tapping screws to tighten M5 nuts (also made of stainless steel) to the traverse at the required points:

The bracket with the antenna element, with its mounting hole in the center, fits tightly onto this nut and is practically motionless.

This is what the completed antenna assembly looks like:

Here's a larger plan:

To attach the active element I used this piece of PCB:

Some clarification is necessary here. I drilled a 5 mm hole in the center of this PCB plate. under the active element, then I made a cut 15 mm wide in the center at about 1/4 of the thickness of the plate, so as to slightly “touch” this 5 mm hole.

Next, I simply hammered the halves of the active elements on each side into the textolite plate so that there was a gap of 5-6 mm between them. So the halves of the active element are held together only by friction (and they are held very firmly, I must say).

All that remains is to grind off the protruding side surfaces of the halves of the active elements with a file inside the cut to give them a flat shape and screw the cable to them through the mounting tabs.

And here is how the textolite plate is fastened to the bracket for fastening to the traverse:

Here is a view of the crosspiece for attaching to the mast. I think everything is clear here without comment:

Although, still O It’s worth mentioning the manufacturing technology of U-shaped staples. In principle, they are on sale, but there is one small “but” - their wild price. 400 (four hundred) rubles per piece. But you need 4 of them. Well, somehow this is completely too much...

Well, I'll do it myself! A meter-long galvanized rod with an M5 thread already cut and costing 50 rubles, a blank for bending, a vice, a red heat-shrink tube, plus straight hands - that’s, in general, all you need to make such brackets. In my opinion, they turned out well. In addition, the heat-shrink tube prevents the traverse from turning in such brackets even when the M5 nuts are loosely tightened by hand.

Well, in conclusion, two more photos: the disassembled antenna and already folded into a carrying case (made by Katya, UB0LAE):

In general, a few hundred rubles and a couple of evenings spent on this antenna - that’s the price of a 2-band yagi :)

And finally something like an application:

And here are the SWR graphs for the antenna described above. I took it with a Kuranishi Instruments RW-211A SWR meter. The SWR values ​​exceeded all expectations (in the good sense of the word):

Vadim, UAØLTB
Vladivostok
10/14/2011

At the time of writing this article, I have already used this antenna 3 times in different conditions. There are, perhaps, only complaints about the traverse itself - after all, the polypropylene pipe is not rigid enough. During transportation, it often bends and has to be straightened.

Chinese collinear VHF antenna for fixed installation. Judging by the reviews, the antenna is not bad.

The autopsy showed that, if desired, such a structure can be made independently.

First, let's look at the stated characteristics

The delivery set includes an antenna, counterweights, a metal tube and brackets for installation on a mast

Installation instructions

Complete photo

Now comes the fun part. I unscrew the star bolt and take out the antenna elements from the plastic pipe. Photo clickable

Phase shift coil

Matching circuit at the base of the antenna. I wanted to believe that the reel was wound on fluoroplastic, but it was still polyethylene. Protection against static is ensured by the fact that the antenna elements are grounded DC. The central core of the cable is connected through a capacitor

The antenna arrived with the capacitor terminal sealed off from the coil. I had to solder

The most difficult element to manufacture

Counterweights in the amount of 6 pieces

As the SWR measurement showed, the antenna is perfectly tuned. The SWR value at the boundaries of the 2m and 70 cm ranges does not exceed 1.2, in the center - 1.

The “wave channel” antenna, also known as the Uda-Yagi antenna, or Yagi antenna, is an antenna consisting of active and several passive vibrators located along the radiation line parallel to each other. In Soviet literature, the name “wave channel” was used, which remains common in Russian-language literature, in English-language literature names are used after the names of the inventors.

The Yagi antenna for the amateur radio section 430-440 MHz was made according to the following drawing:

Cross beam made of metal-plastic pipe, elements made of aluminum wire, 3.5 mm in diameter.

This antenna was originally made for the Puxing PX-2R radio station
and initially it was done like this:

This is the first antenna, and it was made like this, from everything that was available at that moment, a wooden batten and copper wire with a diameter of 2 mm, but even for such an antenna installed in this way outside the window:

I managed to catch a taxi:

And some kind of radio program, or radiotelephone (I still don’t understand):

After remaking the antenna as normal, I already received not only taxi drivers, but also local radio amateurs, but poorly

Then it was decided to put the antenna on the roof
For this purpose, a mounting device was made to the antenna

after which the antenna was fixed on the roof and tested:

After this, the question arose with the cable, since I live on the 7th floor in a 9-story building, the distance to the roof, or rather to the antenna installation site, is not very small, so the cable needed 30 meters, it was decided to buy an RG cable -11, since its attenuation is 9.02 dB/100m.
We purchased 30 meters of this cable:

Since the mast for the antenna has been there for 30-40 years and no one touches it (except me), the base of the mast has turned into this:

and the mast itself was supported by one single guy rope, so it tilted quite a bit:

I had to strengthen the mast with guys

As it turned out later, the antenna had to be attached to the “tail”, and the cable also has an effect (in this case, run along the boom with reverse side from the canvas, and from the “tail” downwards), by the way, in the photos of testing the antenna, the cable laying was almost perfect. And the guy wires can simply be secured under the antenna, and it is highly advisable to well seal the cable connection points to the active vibrator.
The cable from the antenna was routed along a metal fence at the edge of the roof.