Local Emergency Communications with NVIS - Let's Build an 80m/40m Dipole 

No question about it! The dipole is an easy, inexpensive antenna to build, and it is very reliable. I've built several, and for NVIS, I think the 40-m is ideal. Very good video! 73 KI5KET

NVIS is one of my favorite configurations. 👍

Here's a couple of ideas for you. Rather than spreading it out like a dipole with a center mast, put one leg of the dipole between two trees, and fold the other leg of the dipole underneath and in parallel with it, laying on the ground. Also try taking the length of wire the same total length of your dipole, and placing it underneath your dipole on the ground. This is what's known as a passive reflector.

Infantry RTO here. Your hasty antennas are spot on. Keep up the good content!

Enjoyed this video alot! New General myself and I am trying to build this antenna myself. Thanks! From Milan Tennessee.... formerly of Payson, Arizona 🙂

Excelent Job Gastón! A small contribution from me, adding a 1:1 small balun to your dipole will help in not radiation of the coax, a bit less noise as well. Great videos man. 73

Excellent video. I've been a ham for 40 years and have always been interested in NVIS, but never tried it. I'm going to put this together and give it a shot. Thanks for the video!

You say you are a newbie to amateur radio. You come across as an old timer. Great going! 👍

Great video. Constantly get 300-900+ km on 40m running JS8Call 10watts with 40m dipole 5 feet above the ground. NVIS rocks.

FIRST…THANKS FOR MAKING THIS WONDERFUL VIDEO…I HAVE BEEN A HAM SINCE 1978 AS IS MY WONDERFUL WIFE…I TOO AM NOT VERY TECHNICALLY MINDED I LOVE HAM RADIO BUT WE HAVE A VERY COMMON PROBLEM…MANY HAMS MAKE HAM RADIO TO DIFFICULT FOR OTHER HAMS ESPECIALLY NEW HAMS! I AM SO GLAD TO SEE THAT YOU AND OTHER NEW HAMS COMING INTO THIS HOBBY…YOU ALL ARE A BREATH OF FRESH AIR AND VIEW POINTS! YOUR EXPLANATION OF THIS SUBJECT IS EXACTLY WHAT IS SO LACKING…CLEAR AND SIMPLE PERIOD WITH NO BS! SO REFRESHING TO BE SURE…THANK YOU AND I JUST SUBSCRIBE TO YOUR CHANNEL …WELL DONE SIR…I ALSO SEE A FEW FRIENDS THAT ARE HERE KM4ACK JASON IS JUST ONE OF THOSE…I LOVE HIS CHANNEL ALSO…73 AND KEEP UP THE GREAT WORK!

Thanks, I have been researching this subject myself, and your overview is the most helpful overview I have found. Your right, the information out there on NVIS is overly complicated. It is great to see a common sense explanation with a real world example.

Excellent. Very informative.

You are doing an EXCELLENT job of being an Elmer! GREAT JOB. Thanks for your efforts and Videos.

some good ideas! thank you for the ideas!

I enjoyed watching your videos, this one was spread through the club members here in Morocco as we conducted our 1st time ever EmComm drill. 73 from Africa

NVIS has long been a special interest. I had never tried to actually build my own antenna's, and I've been doing this for years. Thank you. Great job.

Dude this is PERFECT. Thanks!

Very interesting. I'm gonna have to build one. Thanks for the video.

Nicely done, sir!

Great video, going to make a 40 meter dipole this weekend. Very simple design, very doable.

I really liked this antenna! Very simple, practical and functional

Great video, worked well, them bnc/post adapters are excellent for easy dipole centres. I built mine with one from Claude’s VE2DPE Design using 300ohm ladder line, linear loaded by shorting each end, reducing the total length by 33% , 44ft instead of 66ft. Mounted in a flat horizontal config. Worked very well at about 8ft above the ground. 73 de M7PBX.

Excellent video. Many thanks.

NVIS as far as I am told was first stumbled upon by the army in WWII we operators on the Gulf coast have been using it since the 90's for after storm Emcomm work since pretty generally the trees are gone or broken. Also as you have found 4 to 5 foot works great, we are deploying it as a go-kit item for Winlink stations to relay messages from VHF stations in a 25 mile radius to the state EOC in Austin and it makes the hop easily and can be used on low power to conserve battery. You are doing a good job keep up the work de WX5GC ARES district 9 Southeast Texas 73

Just got my general and spent the first week on air using a 40M and 20M antenna following your video instructions. I've been very interested in the NVIS configuration and both antennas have worked great. I've actually been surprised at how far I can get out given how close to the ground the antenna is. Greatly appreciate the info.

Great video. Not showy. Not overtechnical. Frugal. Good base knowledge.

Thank you; well done!

Thanks much for sharing; I need to get into NVIS and more comfortable with HF in every aspect. Greatly appreciated

Thank you for all of your videos. My 40 meter dipole was different in that I used a 1:1 balun (somewhat heavier gauge wire, also)=. So much material that I read showed the balun that I thought it was a given. With more research, I found people like the DX commander doing wire antennas WITHOUT a balun. The balun adds weight and cost - whether it has any benefit I will test by doing a side by side comparison. I am new to ham radio, and am learning every time I get on the air. Keep it up!

very impressive demonstration!

well done

Great build and very informative video. You have inspired me to build an 80m as well. Thank you and 73!

Thank you Gaston! It was because of your videos that I decided to upgrade to General. 73

great video!

Well done! You could also put the 40m and 80m antenna wire on the same BNC-Banana plug as in an inverted V configuration, it would look look like an inverted X though.But you would have both bands ready for NVIS. 73!

Great job Tech Prepper! I have been using VHF for a while and just bought my Xiegu G90 and am looking at a number of antennas. I bought a couple, but want to make one on my own and learn abut antenna theory. This antenna is on my "Gotta To Do" list. Again, awesome job.

Good job.

Man this is so cool! It's daunting though!

Good demo!

Outstanding

I am trying to learn about ham radio. You helped make the building of an antenna more easily understood. I just bought the ARRL book to study and plan to test in the next month or so. For me this is a dual learning curve, learning the jargon as well as learning the technical aspects.

love it just love it well done.

Great video!

Extremely cool video, thanks!

I really enjoy all your videos Gaston, but particularly this one involving NVIS communication. Thanks for the work and dedication to making these videos, you do a superb job and your presentation style is brilliant. Videos like this encourage amateurs and bring out their resourcefullness. I subscribed today and gave the ol' thumbs up. If you ever find that the legs of the NVIS dipole sag a little on bands like 80m, you can always use some 5-6' wooden stakes with a small notch cut out on the tops of each of these stakes. Pound them into the ground a foot or so and lay the legs of the nvis dipole into the notch cut out on the top of each stake. The stakes can be placed every 20' +/- down the length of each leg and then guy the ends of the two antenna legs with some light cord and a small stake pounded into the ground (a form of guying I guess). I typically use fishing barrel swivels tied to the ends of each leg and then use the interlocking snap on these swivels to attach to some light line like fishing line tied to the stakes. More videos like this concerning your experiences with NVIS would be cool! 73, Brent

This is a great start. Thank you for the info. Time to get my General.

Great vid! I use NVIS fan dipol (80-40), works great. 9A3GVD Radio Adventurer.

Thanks.........

Here's a 'cheap-ham' tip. Next time you use a fairly wide zip tie, save the cut-off for wire insulators. Very strong. Drill 'em out the same way you did the Cascade Pod plastic.

Keep up the work. You’re a bit further in licensing than I. Keep learning and being curious.

New subscriber,great video thankyou

NVIS works great. If you run another wire 1/8 wave below it more grain straight up

You are crazzzzzzy, But you are my kind of crazzzzzzy... Good Job..

That’s a slick ass move ass move

Great video, thanks! 73

Nice. Just ordered those binding posts so I can play too. Kansas eludes me on my WAS. Gonna give this a go. Thanks.

Great video! Love the mouse pad! :-)

Clever, well done.

Great video brother! Love the channel! W6AEF!

Your intro got a subscription from me . Lol and I’m interested in nvis antennas ..

A 3D printer would be awesome to have, but there is nothing wrong with recycling something like the Cascade lid. Cool video.

Thanks for this posting of this relevant ARES/EMCOMM topic. Based on my modeling using the EZNEC Antenna Modeling software of the original antenna design by Dr. Carl Jelinek, N6VNG (SK), the following info may be beneficial: Using his original mast height of 15', an 80M antenna leg length of 38', with the antenna end heights of 2.33', and a 40M antenna leg length of 25' with the antenna end heights of 6.67', the results for 80M shows an antenna gain of -3.29dBi. For 40M it shows an antenna gain of +1.25 dBi. There is a resonant frequency at 5.8 MHz with an SWR of 1.16. Making modifications only for the resonant frequencies used for EMCOMM in my state of 3.9MHz for 80M (57.5' leg length) and 7.2MHz for 40M (30.75' leg length), and not changing any of the center or end heights, there was a slight increase in 80M gain to -2.01 dBi and in 40M to 2.57 dBi. Making additional modifications using the same resonant frequencies with the 80M leg length still at 57.5' but raising the center mast height to 30' and changing the heights at the ends of the antenna to 12.33' above ground, the gain is now 3.15 dBi. A greater than 6dBi increase from the original. With the 40M center also at 30', the leg lengths have now changed to 29.25', and the end heights have now changed to 16.67' above ground, the results shows a gain at 5.65 dBi. A 4.4 dBi increase from the original. In summary, even with the low signal-to-noise ratio exhibited by a received NVIS signal, improving the gain can allow the antenna to radiate more in the vertical direction. Charles NM5CR

I remember another NVIS item that putting a reflector wire directly under the NVIS antenna enhanced the vertical component of the antenna signal like a yagi. You might need your driven element to be further off the ground to be more effective though. Doug, VE3MCF, AK4HB

With things being what they are. Wire for 40 and 80 is great. Just off the ground and not getting 6 to 7 feet. Out in the swamp it's great 👍

Love the visualization with the water, those types of examples help knuckle draggers like me 😂

You might want to have a search in YT for Speaker wire antenna, quite similar to your configuration without even needing the coax!

I have had great success just past the ground wave distance on 40 with very low dipoles. I will note that wires in very close proximity to the ground have a lower velocity than antennas at more normal heights and therefore the resonant frequency will be lower quite a bit. I once had an 80 meter inverted V and could change the resonant frequency from the SSB to CW band by lowering the ends! I also take advantage of this with my Beverage receiving antennas by putting them directly on the ground. 73 de N4DJ

Nvis is my way to communicate from valley tp valley here in the mountains of Switzerland 👍 Recycling is the better way than 3 d printing 👍🇨🇭 Great. Video thanks and 73 de HB3XBL 👍🇨🇭

Adding this to my survival set up. Gotta upgrade my license to get on the HF

I also know that NVIS can do long distances if you mount the antenna about 10 feet off the ground

Add small metal disks to the ends of your antenna to broadband the antenna.

More Hams need to know this stuff. I attempted to get my local friends interested starting 10 years ago, but they had no time for it. Even as survivalists, they are still not interested. Younger guys will have to lead the way, and there are precious few young guys who are serious about survival comms. NVIS propagation will be essential if repeaters go down. If using terrain advantageously, DFing is nearly impossible. And that is a fact few are aware of, or appreciate in this day and age. If using 160 meters, there are other advantages as well. They may have to learn the hard way. Be ready to reintroduce short skip propogation once the time is right. For now, most Hams will stick with the narrow bandwidth and ideas that define amateur radio.

Put round terminal connectors on the wire, saves the post trying to crush and cut through the wire Loved your video

Great stuff. A lot of theories regarding NVIS that are iffy if you ask me. If it works, go for it. NVIS is suitable for portable / SOTA. Just a thought, it would be very easy to make it linked as well.

Another advantage of NVIS is it makes it harder to triangulate. Signal is coming from the sky.

Best antenna height for high angle propagation is an antenna height of 0.15 to 0.25 wave length.

Great video, thanks for sharing this technology. Clever demonstration with the hose. Can you also share a link to the soft case you used to package it up for portable use, please?

We deploy NVIS antennas quite frequently in our State Guard, as we're not really interested in communicating much beyond 300 - 400km or so. It's a remarkedly effective technique.

Loved it. I've been too busy with other items to get an antenna going for an HF rig I was given. All the options were too time consuming and/or expensive. Decided recently to just get something simple up. Looking at going the octopus hamstick route - pretty cheap. But not really NVIS. But having both would be cheap and cover the necessary emergency basis I am looking for. I'm like you - I JUST NEED IT TO WORK. I'm not looking for bragging rights - but about acquiring desired capabilities for an undesired future need. RH

I've been getting ready to put one of these together for a while and now that the snow is gone i can get out more to play with this stuff. Glad to see someone putting it into action and getting good results. 73 de W8MJL

Good Vid son, I echo OH8STN, Julian, place a REFLECTOR Wire directly under the xmitting wire as a reflector, works great

7:30 nice wire stripper which doesn't damage strands of wire, as opposed to the pos used on some other youtube channels!

These simple antennas work absolutely great. They're cheap, portable, and lightweight. Get a few BNC binding post adapters (cobra heads) to keep with your gear. If you're going to buy one, might as well get a few. Grab some wd-1/tt field wire for antenna wire. For around $100 bucks, you'll have a kilometer of wire that's got a tough jacket, copper and steel strands for appx 200 pounds of tensile strength, and is easily soldered. Don't forget about 60 meters either, it's a great band that has some of the best characteristics of both 40m and 80m, and there's usually not a lot of chatter on it either.

Your efficiency will rise at somewhat greater heights, up to about 1/8 wavelength. If you also run a slightly longer wire on the ground under the dipole, you can lessen your nominally -3 dB loss heating soil. Note that your swr bandwidth will be less leading you to believe it's not doing as well - but that's only because the resistive soil isn't swamping out the antenna impedance as much.

Good stuff! I'm supposed to be giving a talk on NVIS to my ARES group. Like you, I'm fairly new, but I think NVIS is a great method.

If I seen you your video sometime ago I would have already shared my experience with nvis. Several years ago I was estate director for navy-marine Corps Mars living in North Dakota. It had been snowing for sometime and I needed to call the net SD/ND. My g5rv antenna spell the ground it was lying on top of the snow(6"). What the heck! I called and it anyway. To my surprise Communications? FINE! I hope it worked as well for you Jack KC7JS/NNN0ZBE

Yup, we can tell you are in Southern Arizona by the Plants behind you!

Super light coax say rg174 is fine for those freqs and would fit in that kit

Though the antenna is an important part of the overall NVIS configuration, you have to be able to pick the right frequency. There are resources out there for this, especially for NVIS. Remember, NVIS comms rely on the signal being reflected back down at very acute angles. Choose the wrong frequency and the signals will go straight through the ionosphere and not be reflected back. This is why you see most military HF rigs only go up to 60mhz (or so).

From what I have read, the Passive Reflector wire on the ground should be cut + 5% longer than the antenna.

I'm new to building antenna do you trim off the excess legs or do you just keep them wrapped around?

You’re silly but I like you anyway. That’s why I subscribed. 11:35 and here is where the Tech Prepper got himself into trouble!

I'm really enjoying your channel! I'm a new ham as well and working towards my General license now. If one were to setup a properly-tuned end fed half wave antenna in a horizontal configuration do you think you'd get similar results?

#ThNHR #TeamReplay for the win!

Brand new Ham here. Love the videos. I am focusing on NVIS as my first set up unfolds. I have a question regarding mobility of the system. Will it remain functional to mount this type of antenna on a loom type rack, maybe 4 or six inches between each pass of the wire and mount it on the roof of a car or truck? My thoughts are to remain truly mobile with the system.

You didn't show it but I presume you ran the coax direct from the BNC binding post to the rig.

you repeatedly said that you are a new ham,but actualy you are master for other.yiu taught every thing of hf antenna for novice

Enjoyed the video as always! Nice work on the antenna! Where’d you get the binding post from?

Hi, I was looking into how the banana connector works and from what I see one side is the wire in the coax cable, and the other side is the ground. Why do we connect a wire/antenna on the ground side? Does it also contribute to the signal? What would be the difference between that and only connecting a wire on one side, not on the ground?

Outstanding video! I enjoy using NVIS, and used to discuss it quite a bit on the website I used to own (Doomsday Prepper Forums.com).