How To Make A Simple Small Space Ham Radio Antenna For 40 Metres (Plus 2 Other Bands!)

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How To Make A Simple Small Space Ham Radio Antenna For 40 Metres (Plus 2 Other Bands!)

Рет қаралды 4,924

Күн бұрын

Here’s how I made my three band no radials vertical for 40,20,10 metres.
Including the design, lengths and tuning.
Coil calculations website is here:
www.66pacific....
Connect with my channel by subscribing and commenting.
Any antenna ideas or questions? Email me:
TimG5TM@icloud.com

Пікірлер: 62

@kevinnicholls1017 9 күн бұрын

Another helpful video. I cannibalised exactly this antenna just last weekend. I had built it as a shortened EFHW for SOTA and holiday locations where space is limited. I deployed it as an inverted V and found it very sensitive to the height of the loading coil and unpredictable in different settings so I abandoned the idea. All that I needed to do was to watch your video. Setting it up as a vertical gives a predictable height for the loading coil and repeatable antenna! Good work. Thanks MW0KXN

@M7BCN 3 ай бұрын

Great work buddy, looking forward to the next one. Thanks Tim.

@timg5tm941 3 ай бұрын

Thanks Brian!

@mrkopecky 3 ай бұрын

I guess I could use same theory to make a “sporty 40” coil. Thanks Tim.

@timg5tm941 3 ай бұрын

Absolutely. You can load the top of a 5m Q wave and add about 1.5m of wire to have a 20/40 ground mounted vertical with ground radials using the same coil.

@R50_J0 4 ай бұрын

I have three of the Atlas meters. Kind of non-traditional looking but they’re accurate and excellent quality.

@timg5tm941 4 ай бұрын

Indeed they are!

@32_bits 4 ай бұрын

Its possible to measure inductance and capacitance with your Rig Expert, check the device menu.

@timg5tm941 4 ай бұрын

Nice! I will

@IrishHamRadio 3 ай бұрын

Ah wonderful Tim!! I’m now definitely more enlightened and getting closer to having a go at one of these choked/loaded antennas with my own coil…. I understand now how you make and measure the coils, but silly question however…. How do you know how many uH you need?? I know I should probably know this!! 😅

@timg5tm941 3 ай бұрын

As a ROUGH idea. Look at the 1/2 wave on feet on the band you wish to choke and that gives you a good idea of the uH needed. So for 20m 33uH and 10m about 16uH seem to do the trick Dave.

@IrishHamRadio 3 ай бұрын

@@timg5tm941 ah ok class! Got it 👌🏻 thank you 😊

@mareksp9tkw908 3 ай бұрын

TIM this antenna as vertical works well on 20 and 40, 10 on another hand is poor. Much better to set it up as inv-L with transformer 2mtr of the ground apex at 7mtr and rest on antenna as horizontal as possible. When you model it you will see that 10m give a quite a good performance.

@timg5tm941 3 ай бұрын

Fully aware of that difference. Of course it’s main benefit as a vertical is enabling 40m without any radials. For 10m it’s 3dBi down compared to a 1/2 wave mounted at the same height at a 5 degree elevation angle. Not a huge game changer and still capable of DX. I’d classify poor as being 2-3 S points down. On 10m this antenna isn’t that bad. 73

@paulsengupta971 4 ай бұрын

I've got a coil ready to put up a 40/20/15/10 EFHW and have it work on (at least a bit of) 80m as well. The plan is to run it over my house roof and down the garden. I appreciate it might not work properly in the rain! :-)

@timg5tm941 3 ай бұрын

Give it a go Paul!

@johnsonstechworld 3 ай бұрын

Oh! I see that somebody is already about to try my plan for 80m when the solar cycle 25 goes down! 73 de Jon, VU2JO.

@paulsengupta971 3 ай бұрын

@@johnsonstechworld You can get commercial coils to do this, I've actually bought one second hand, but I'm going to create my own for another antenna.

@johnsonstechworld 3 ай бұрын

@@paulsengupta971 It is not that easy to locate one in this region. May be I will try to make one. I was wondering whether I can use 1 sq mm insulated electrical wire from local electrical shop? It is there just across my home. The coil might turn out to be quite bulky and heavy. For the regular enamelled copper wire, I have to hunt in the city with hardly any parking space near such shops over here!

@paulsengupta971 3 ай бұрын

@@johnsonstechworld I have made ununs and coils with solid core mains electrical wire, they work fine.

@markramsay6399 3 ай бұрын

Great video Tim, Thanks. Mark, 2E0MSR

@timg5tm941 3 ай бұрын

Thanks Mark!

@johnnorth9355 4 ай бұрын

I am going to take down my EFHW and my Vertical and use the bits to make something a bit different . The goal is to get away from the local QRM of Solar and other electronic device noise. Desperate times call for desperate measures . Quite what I am going to do I am still working on . Oh er ! 73 M7BLC.

@timg5tm941 4 ай бұрын

Good project!

@brianfields4479 3 ай бұрын

Personally I would leave the vert up , and work on a rx ant. 73 zl3xdj.

@johnnorth9355 3 ай бұрын

@@brianfields4479 I am intrigued by the idea of a loop on the ground around the outside of my garage for rx but have yet to work out how I can automatically switch antennas for rx and tx. I am a limited knowledge late life M7 after all 🙂.

@brianfields4479 3 ай бұрын

@@johnnorth9355 there are tx/rx auto switches on the market. I myself made a ant auto switch using a switch output from my rig. I use a resonant vertical for 40m and one on 20m, fed with one coax, and on rx I use a low to the ground dipole on rx, but loops on the ground work very well. 73 zl3xdj

@genoa1979 3 ай бұрын

This antenna for portalble in 40 meter have good angle for dx?

@GM5DDX 3 ай бұрын

Could you make one for 10, 15 and 20?

@timg5tm941 3 ай бұрын

I have done - check out a video I did a month or so ago, using traps.

@M0JSX 3 ай бұрын

Excellent video Tim. I wonder what the radiation pattern looks like on 10m? I know on a “standard” 40m EFHW, the pattern is a little erratic up on 10m (while it does technically work).

@timg5tm941 3 ай бұрын

It’s slightly down on the 1/2 wave as full waves exhibit higher lobes (-3dBi at 5 degrees take off). The earlier video I referred to towards the beginning of this one (link on the screen) covers the modelling. 73!

@M0JSX 3 ай бұрын

@@timg5tm941 thanks Tim. I did watch that video too! I'll blame the early hour!

@timg5tm941 3 ай бұрын

@@M0JSX no worries mate!

@johnsonstechworld 3 ай бұрын

Currently I have squeezed in 40/10m inverted V fan dipole into my small space. When the solar cycle 25 starts going down and 10m goes down, I will try to use coil loaded dipole for 80m. Or should I convert a 40 to 10 m EFHW which I purchased and currently in my shelf, with a coil to work for 80m as well? I presume that 20m long wire will be too short to make it work on 160m as well? 73 de Jon, VU2JO

@timg5tm941 Ай бұрын

Any of those would work. A 20m long wire is pretty short though for 160

@johnsonstechworld Ай бұрын

@@timg5tm941 Thank you. 73

@Sidmi5utc 3 ай бұрын

Hi Tim, same as the Hyendfed antenna which I think you have ?? I wonder have you compared the 2. After seeing a previous video of yours with the 12m pole and the hyendfed I bought the same and it seems to work well. Great to have a go at building one, good work !! Just need this weather to improve so we all can get out a bit more. 73 Sid MI5UTC

@timg5tm941 3 ай бұрын

Hi Sid! Yes its the same design and I am glad to say that this design replicates it. They are very well made antennas aren't they? I would say there is no difference between the two antennas. Great to hear from you. 73

@M7BXR 3 ай бұрын

Have you had a trip back to Wales Tim? Sounds like youve had an accent top up! 🙂

@timg5tm941 3 ай бұрын

I spotted that too! I usually get more Welsh if I get tired or speak with family/friends from back home. I think I was tired this day! 73

@davidbridge3542 4 ай бұрын

Sounds like one to make. If i found the details for my coil based upon my size of wire and pipe dia, could i make the antenna in one continuous length ? It was only your testing explanation at the end that gave me any doubts??

@timg5tm941 3 ай бұрын

Yes you can do this although bear in mind that if it is short then it becomes more of a headache to add wire. I like to keep my coil detachable as I have other plans for it for other antennas. 73

@siddharth4662 2 ай бұрын

can you show the working of this antenna please if possible!

@siddharth4662 2 ай бұрын

got it! :-) thank you very much... i owe you a beer if I ever come back to England again! :-)

@timg5tm941 Ай бұрын

You're on!

@HamRadioQso 3 ай бұрын

How well will that work at let’s say at a 45 degree angle?

@timg5tm941 3 ай бұрын

You mean as a sloper? It’ll be fine .. often used that way

@HamRadioQso 3 ай бұрын

@@timg5tm941 I thought it would be. Thanks for the reply

@brianfields4479 3 ай бұрын

Interesting ant Tim, would the ant gain anything if radials were added do you think. 73

@timg5tm941 3 ай бұрын

Not as it’s a Halfwave no

@MikeN2MAK 3 ай бұрын

I see an LCR meter in my future.

@chazwozza67 3 ай бұрын

Where all ya CB videos gone?

@timg5tm941 3 ай бұрын

Into the mists of time!

@daveengstrom9250 3 ай бұрын

Sorcery!

@timg5tm941 3 ай бұрын

Indeed!

@thesisdavid 3 ай бұрын

Hi Tim, What is the lowest radiation angle we can get on this antenna for DX?

@timg5tm941 3 ай бұрын

Hi there - at 5 degrees elevation its best band is 20m, about the same as any half-wave vertical. On 10 and 40 its around 3dB down on a similar style antenna.

@spython1553 3 ай бұрын

Tim, another great video! How do you calculate the lengths of the radiators and the required inductance of the coil for the bands you want?

@timg5tm941 3 ай бұрын

Hi there. The radiator lengths: cut 10m initially for the lower longer part - this is a 1/2 wave on 20 and full wave on 10m. It is important to also attach the coil but not yet the top shorter wire, Trim the lower wire until you get a good match on 20 and 10. Then attach the top wire (initially about 1.8m) and then cautiously trim that for best tune on 40m The lower longer wire is barely affected. As for the coil, the 35uH inductance is important in that it provides enough impedance to choke off 20 and 10 and present enough loading to make 40 usable and fit on to a 12m support such as a fiberglass pole. 73

@spython1553 3 ай бұрын

@@timg5tm941 thanks for the detailed reply!