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vhf beam

im starting to think about building a vhf beam for fm mainly and wondering if anyone can point me towards some good plans to build one please ?

Idea was to use some pv conduit and build a 3 element one , and want a simple design and easy to bread down .

Matt 2E0FGX

Hi Matt

Try this hombrew 4el 2m yagi with a PVC boom. All elements are stored in the PCV boom. One of the features of this PVC boom design is you can easily slide the elements to find the optimal 50 ohm impedance.

Good luck with your 2m yagi project.

73, Andrew VK1AD

I have made a 2 element using this.
http://www.hamuniverse.com/wb2vuo2elyagi.html

I used 2 TV rabbits ears antenna on a Fiberglas mast. I marked the spot to collaspe it too with a Sharpie.
A recent field test with it at about 1 mr high resulted in a contact at 103 km using a HT at 5 watts.

Malen
VE6VID

1 Like

If you’re already carrying a telescopic pole for HF, consider a Double Extended Zepp wire antenna hung vertically. This antenna has worked well for me on FM out to almost 200 miles from a mountain top. Since it’s omnidirectional, you don’t have to deal with pointing the antenna, and it gives you a few dB of gain over a dipole or J-Pole.

Thanks guys some food for thought there , i carry a 6m pole for my vhf vertical but im thinking be nice to see if can get some distance .
Matt 2E0FGX

I’ve built an EDZ like Adam described, and it had worked very well for me

I’ve built a few of these and they work well:
https://www.qsl.net/dk7zb/start1.htm
Click on “2m/70cm-Yagis ultralight”

I like the 4 ele 2m beam because the boom length is about the same as the elements so it packs up well.

73 Mike G7HEM

Adam,
Center feedline or end??

Malen
VE6VID

Center fed. I use a short length of twinlead (about 8") to get a nice 50 ohm match. The elements are 5/8 wavelength.

I have experimented a bit with adding wire reflector and director elements, separating them with spreader bars. It’s pretty cool, but I don’t think I have my element lengths quite right yet. Theoretical gain is around 10 dB directed at the horizon with a ~110 deg 3dB beam width.

Adam
K6ARK

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Here is a link (pdf download) to a simple design that is very similar to the original 2m SOTABEAM:

https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.arrl.org/files/file/Technology/tis/info/pdf/9304054.pdf&ved=2ahUKEwiiheDL8fzhAhVdSRUIHeDoBRwQFjAAegQIBBAB&usg=AOvVaw0UnGXfFixqEiWppmMPZpTt

I keep meaning to knock one up myself.
73 de OE6FEG
Matt

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Or if you have - or know someone with a 3D printer - have a look at my 2m band moxon design.

73 Joe

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Matt, have a look at the pages by Martin DK7ZB if you haven’t already done so. It will help with ideas. As Joe suggests, you might consider a Moxon. Mine doesn’t fold, but straps to the backpack and with rounded corners doesn’t snag things.

73, Gerald

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At https://www.qsl.net/dk7zb/start1.htm you can find a lot of interesting antennas.

For me the most interesting antennas would be the wire antennas (loops). They are easy to build… have some gain… you can fold it like an umbrella… and fix it easily at the pole.

73 Armin

I’ve been playing with an EDZ since you posted this. Finally got it to tune where I wanted yesterday and tried it out comparing it to my 2 element yagi and a MFJ Long Ranger EFHW telescoping antenna.
Ken VE6AGR was home about 50 km away. The yagi was about par with the EDZ. Yagi was about 1.2 mr high and the feedpoint of the EDZ was right around 2.5 mr. To me its a keeper and will in my antenna pouch with my 20/40 dipole.

Malen
VE6VID

Awesome Malen, glad you got it to work for you! I really like the antenna. It has served me very well.

Adam
K6ARK

Although no longer selling aerials or kits, there are plenty of designs available at http://www.nuxcom.de/downloads/
That will give you some ideas, which you can tweak to suit materials available to you.

Stuart
G1ZAR

I’ve just made a 3 ele yagi using MW0IDX design which is very similar to one above. http://mw0idx.co.uk/idx3elementyagi.html I used it this weekend and got some good reports.

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All these lightweight designs are good for occasional VHF activators. Those who want to activate frequently on VHF are better off with a more rugged mechanical design. My first portable VHF beam was a 4 element DK7ZB with a 1 m boom. I used those plastic clamps and each of them didn’t last long. Their fit gets looser the more you use them. Especially in winter, they break easily. Hard to keep the directors in place when its windy.

In summer 2017 I built ‘5-Elli’ and I’ve been using her since. She’s a 5 element 28 Ohms DK7ZB 8,5 dBd with a 1,5 m boom, packs at < 60 cm, is less than 600 g. No tool needed to deploy or disassemble her. Good in winter when the fingers get cold and wet…

The elements are of 8 mm diameter (driven element 10 mm) and are held by electric fence wire & rope insulators which are perfect for 8x1 mm aluminium pipes. The elements consist of two halves which both have rivet nuts and one has a headless screw. So they easily screw on each other. The driven element is a little bit different, you get the picture. The brown 75 Ohms coax’s are the transmission line 28 -> 50 Ohms.

The mast mount is made of two lightweight clamps from the hydraulic supply. It didn’t fit exactly to my pole at the desired height, so I put a piece of plastic pipe in it.

If you look closely, you see the antenna is ‘hanging’, which means the boom is below the mast mount and the elements are mounted below the boom. This gives more stability to the complete system including the glass fibre pole.
5 Elli is even capable of EME. :wink:

Last autumn, 5 Elli got a sister. :sunglasses:
The complete system including the stacking harness is less than 1,9 kg. Quite lightweight for 11,3 dBd, I think.

Ahoi
Pom

4 Likes

Hi Matt,
fair play to ye, I love building antennae.
It’s all about experimenting, failing and trying again.
My advice is to get an antenna analyser and the ARRL Antenna book. that gives you loads of scope for experimenting without the risk of busting the front end of your transceiver.:persevere:
Well done.
73 Frank EI8HIB

I went for lightweight (~200 grams) for this SOTA backpack yagi. I didn’t want to add much weight to the pack for longer hikes.

Cheers,
Glenn VK3YY.

2 Likes