Simple VHF and UHF dipole antenna
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- Опубліковано 8 вер 2024
- DIY simple dipole antenna for VHF and UHF bands (2m and 70cm).
Works great with RTL-SDR recievers and Baofeng portable radios.
Build instructions: www.amateurradi...
Use dipole antenna calculator for correct dimensions!
SWR Measurements of this antenna: • Homemade VHF/UHF dipol...
#hamradio #diy
Nicely and simple made dipole, longer tubes for 2 meter band and shorter tubing for 70 cm band, also the 2 meter band dipole could work as a 3/2 wavelength harmonic antenna for 70 cm band. Video shows a vertical omnidirectional Antenna but small dipole may have some directional characteristics as being close to the larger dipole. thank you.
Verbatim instructions from the dead link in the description for "Zed Zed's workshop: a simple 2 m / 70 cm vertical dipole antenna":
A Simple 2 m/70 cm Vertical Dipole Antenna:
This easy to build dual band VHF/UHF antenna makes a great project for the new ham that is ready to get on the 2 meter and 70 centimeter amateur radio bands. It can be mounted on a roof top for use as a fixed antenna and it also folds conveniently for travel making it an excellent backpack antenna. The design is simple and so is construction.
Construction:
The antenna elements are made of 1/8" diameter stainless steel rod. Each rod is bent into a tight "U" shape and fastened to the acrylic plexiglass boom with stainless steel hardware. Flat washers large enough to fit across the gap in each element are used to hold the elements in place. A piece of 1/4" thick cast acrylic plexiglass, 18" long and 2-1/2" wide, is used for the boom.
Drill the holes in the boom as shown in the diagram. The position and hole size for the mast mounting clamp is determined by the size and width of the clamp or U-bolt that you use. I used a TV antenna mast clamp that fits a 1-1/4" mast.
Probably the hardest part in making this antenna is bending the stainless steel rod. But the rod can be bent without heating it first with a torch. I was able to bend the rod by placing it in a bench vise. The tricky part is to bend two pieces of rod that come out looking similar is shape. Use two pieces of stainless steel rod that are longer than needed then trim them to correct lengths after the rod has been folded into a U shape. Make each element section as shown in the next diagram.
The hardware for mounting the antenna elements to the boom is also used to connect the feed line to the antenna. The coaxial cable center and shield are separated and the leads kept as short as possible. Crimp-on ring connectors, with the plastic insulation removed, are soldered to the ends of the cable. The coaxial cable center lead is connected to the top section and the shield is connected to the bottom section of the antenna. This antenna was fed with RG-8X (Mini 8) 50 ohm coaxial cable. The feed line used was a random length and was not cut to any specific length.
I used mostly all #6 stainless steel hardware to attach the antenna elements to the boom. Start by placing an external tooth lock washer on a machine screw then insert it into the hole drilled in the boom. Next install a flat washer, then the antenna element, then another flat washer. The ring connectors with the coaxial cable attached go on next then finally fasten with a split lock washer and a wing nut. Repeat for the opposite side.
Tuning the Antenna:
To tune the antenna for minimum SWR simply loosen the wing nuts and slide the antenna elements in or out as needed. Keep in mind that changes made to one band will affect the other band. For example if you shorten the 2 meter length then you also shorten the 70 cm length. Some fine tuning by again trimming either the 2 meter or 70 cm sections may be done if desired but this should not be needed.
All stainless steel element mounting hardware. Use larger size hardware if flat washers do not extend across both sides of the antenna element.
Part list:
2 each 1/8" Stainless steel rod, 3' (.9 m) long.
Acrylic Plexiglass, 18" x 2-1/2" x 1/4" (45.7 cm x 6.4 cm x 7 mm).
2 each #6 x 32 x 1" (25 mm) Machine screws.
2 each #6 x 32 Wing nuts.
4 each #6 Large flat washers.
2 each #6 Split lock washers.
2 each #6 External tooth lock washers.
2 each #6 Crimp-on ring connectors.
Mast mount clamp.
Plastic cable tie or small U-bolt.
(I could not include the picture diagrams as UA-cam does not allow links. One photo shows the measurements for the rod. The steel rod should be exactly 18 5/8 inches in (47.3cm) length. You need to bend the rod so there is exactly 6 ¼ inches (15.9cm) for the short end. The bend should be 3/8 of an inch (10mm) in width.)
TV duplexers that combine VHF & UHF antennas, work great for separating the antennas.
How did the police know soo quickly he made a home antenna? 🤔
czesc,chciał bym zapytac jak sprawdza się ta antena i jak sie ma w stosunku do "duo" j-pole ? czy taką też próbowałes budowac ?
have fun hooking up the feedline kg6mn
Might be easier to connect the cable first by inserting it into the bottom of the pipe, then out to one side.
Thoughts on this type of antenna vs the copper tubing j-pole for performance? This seems more mobile and easier to mount. Any other thoughts?
The one in this video is dual band 150s/460s j poles are single band. If you only need 1 band and want more gain in 1 direction then youd want the j pole. I have a homemade dual band dipole mounted in my attic for my baofeng and it works great all directions. I just used high quality rg6 catv coax and made sure I measured it in half wave lengths and I used an swr meter to fine tune the distance between the elements.
Nice design, good video. How was the reception?
In past I used that with RTL-SDR and I thank that for cheap DIY antenna reception was acceptable.
@@DaedalusLab Would you be able to tell me the distance reception the antenna is good for in Kilometers ???? Thank you fella.
great little project...thank you!!
Does such antennas have better UHF reception because the antenna is larger. Because it includes VHF dipole? Or does it not affect UHF reception or may it fail to receive UHF?
This antenna receive both bands VHF on longer element and UHF on shorter one.
Good idea
Nice Concept!
how its work ..and what about gain ?? this is VU3 YWB
What do you mean by hot wire ?
Is it the innermost copper wire in a coaxial cable or the outer conductive mesh ?
Inner conductive wire
Jak przyłączyć przewód do anteny bo tego nie jestem do konca pewny?
Trzeba przykręcić śrubami w środku, tymi samymi którymi są przykręcone aluminiowe pręty do drewnianego elementu.
What are the measurements of the PVC tube that is attached to the mast? Thank you
I'm not remeber correctly, something around 1m. Just to give some space from mouting point and not to give 1/2 and 1 wave length.
Thank you!
Hi how long must uhf elements be ...
Roughly 1/4 of the wavelength of what he is going for. So for the 2m side it would be ~50cm; for 70cm it would be 17.5cm.
Realistically you want to do some more calculations to find the exact wavelength of what frequency you are using.
What did he say
But how did you connect it to the SDR?
On coax end just attach proper connector.
A gdzie kabel?
How much is the Road Diameter? 3mm is it right? Can I do this Antenna with 4 mm?
Pietro Musian As far as I remember I used 5mm diameter rods. 3mm and 4mm are OK just bandwidth will be a little narrower.
No, you will open a Blac Hol that swallows the rest of the earth if you use 4mm.
@@thebutcherofbenghazi.libya3348 LOL
I couldn't find a stainless steel or even an aluminum... would it okay for a copper brass?
It should be ok, but length need to be tunned a little.
Coat hanger
How on earth do you manage to connect the cables?
Maybe connect them to the screws first, put the cable through the tube and then install it?
73, 55
Radio Vlaanderen Nationaal c
Hii bro I manufacturer from dipol anntenna but how do I
👏👏👏👏👏👏👏
perfect!
Nice video. Do you think it's possible to combine 144 and 220MHz as you did with UHF? 73 de PY5CL
It is. You would need a longer length of material to start with, and and just bend to the mid-range frequency of each band. The reason you need the material to be longer before you bend is because the 220Mhz element will be slightly longer than the 440MHz element he shows in the video. Try it an let us know how it works. 73 de KC0OLH.
How did you bend the aluminum ?
Try filling it wth sand and blocking the ends then bend
I like...good job..!
Hi i fix my aerial and i catch only seven channels ALPHA - ANT 1 - OPEN BEYOND - MACEDONIA - SKAI - STAR CHANNEL - MEGA
skąd bierzesz takei rurki? jaka srednice zastosowałeś? u mnie w okolicy wszystkie metale kolorowe sa sprzedawane od pn do piatku co dla mnie stanowi problem i zdaje sie ze zostaje zakup przez internet i placenie za przesylke. pozdrawiam. jak ci dziala ta antena ? jakie masz realne zyski w dbi ?
Pręty aluminiowe można kupić w dowolnym markecie budowlanym. Ja użyłem takich o średnicy 5mm. Używam tej anteny do odbiornika SDR i działa całkiem dobrze.
faktycznie były w castoramie. dzięki za podpowiedź bo byłem pewny że w markecie aluminium akurat nie znajde. Antena mimo kabla 7 metrowego poprawiła znacząco odbiór. zastanawia mnie jednak jaka była by różnica między aluminium a orginalnie przyjeta w projekcie stalą nierzdzewna
+sebadtable Co do różnych metali to nie wiem jak się to zachowa, trzeba by doczytać. Przy takich częstotliwościach mamy zjawisko naskórkowości i tutaj raczej średnica ma większe znaczenie jak rodzaj metalu.
Daedalus Lab czyli lepiej bylo by isc w koerunku grubszego preta?
+sebadtable Grubszy pręt zapewni większą szerokopasmowość anteny.
where are the electrical connections
Danny OConnor inside PVC T-connector are screws attached to wood element. Cable is attached to this screws.
What centimeters of the antenna?
Steel rod 47.3cm, then bend 15.9cm of the rod. The bend must be 10mm in width
Didnt really tell me much apart from I screwed this to this LOL.
What are the dimensions
Here LZ1DLP
qual o preço aceita cartao ,divide em quantas vezes?
nice.
This video would be much better if I could hear anything...
Witam,
z chęcią bym zakupił u Pana taką domowej roboty antenę. Nie mam na tyle wiedzy aby to samemu wszystko sklecić (głownie chodzi o montaż przewodów itp). Mam radio boafeng uv82. Byłaby możliwość zrobienia takej anteny na zamówienie która będzie pasować do mojego radia? Posiadam ten RTL-SDR na usb ale tutaj jest inne wejście antenowe.
how is the swr? cheers 73s from Canada
Vini kresky answer is on my another video. Check here: ua-cam.com/video/yRjGFTcL4-U/v-deo.html
i like it but i want to watch and VHF chanels
+Krishanka Theekshana This antenna is tuned to amateur band, not commercial TV.
Amrjeetkumar
You were mumbling.... which means you didn't want to talk to me.... g'bye