NVIS Propagation for Ham Radio Beginners!

[@mikesradiorepair]

I used NVIS a lot in the US Army. Percentage wise probably 40-50% of Company and up level communications were done using NVIS. The rest was terrestrial VHF or satellite comms.

[@TheSmokinApe]

Hey Mike, good to hear real world applications like this 👍

[@dirtyeric]

Used NVIS a fair bit in the forces. We didn't use it for 'normal' comms, we used it to prevent others from communicating aka Jamming.

[@TheSmokinApe]

Nice 👍

[@TheSzalkowski]

Great Video. I live in a holler in the mountains of Virginia. I have a home brew AS-2229 inverted vee and I usually run on 40 meters. Normally I can hit Long Island NY down to Georgia and out to Ohio/Missouri on 20 watts of power using Winlink/Olivia/ whatever I am playing with that day.

[@TheSmokinApe]

Glad you liked it, thanks for checking it out 👍

[@Mary-wk6of]

Excellent video The SmokinApe! ☺️ Thank you!

[@TheSmokinApe]

Glad you liked it!

[@csexecutiveservices]

As an Extra class for nearly 7 years, this was a very digestable refresher. Well done de WA1EM

[@larrynavarre]

Fantastic instruction “professor”! I have studied NVIS a lot in the past year and you have done an excellent job outlining the antenna. Particularly appreciated are the diagrams and explanations. And your “art skills” are just fine. Thank you!!! N8LJN

[@TheSmokinApe]

Glad you liked it Larry, thank you for watching 👍

[@75ohmHAM]

Awesome Slides man!!!

[@TheSmokinApe]

Thanks Zig!

[@bendeleted9155]

Outstanding! Thank you, Sir 👍

[@TheSmokinApe]

Thanks for watching, glad you liked it 👍

[@WG5Xradio]

Good presentation. Most of the NVIS that I have seen are inverted vees. If you use two different bands at 90° angles to each other, the antenna itself effectively becomes the guy lines for the mast, and only one mast is needed. I think at some point in the future, I will experiment with both a dipole and inverted vee and see if one works better than the other.

[@TheSmokinApe]

I’m a big fan of inverted V antennas for the reasons you mention but you want reflectivity from the ground, a dipole is better suited for that 👍

[@mikesradiorepair]

@@TheSmokinApe 15 foot pole with double inverted V's like described have been the military standard NVIS antenna for over a half of a century and is what a lot of civilian NVIS antennas are based off of. Simple and it works.

[@TheSmokinApe]

@ somewhere around here I have a paper copy of an old military NVIS guide

[@seanwood8043]

Short and to the point. Informative as always !

[@TheSmokinApe]

Thanks Sean, glad you liked it 👍

[@dougdaniels]

Excellent explanation. I'd never heard of using a reflector in that manner. I may try that on a POTA activation where I'll the have room to spread out that I don't have at home.

[@TheSmokinApe]

Glad you liked it Doug, thanks for watching 👍

[@bwillan]

Very informative video. I didn't know about the reflector on a horizontal antenna.

[@TheSmokinApe]

Glad the video was helpful 👍

[@jameyevans29]

Do more on the reflector dipole please.

[@KustomRadioFrequency]

Great demonstration

[@TheSmokinApe]

Thanks KRF 👍

[@robertmeyer4744]

Great stuff ! Many make a NVIS style for 80 meters and don't really know it. The height above ground. The reflector adds gain . I have had odd DX over summer on 10 meters. Very short. some call that NVIS but are wrong. 10 meter band can have speritac E or tropospheric ducting happen. 6 meters does it more often. I talked 10 meter SSB from Boston NY to NYC last summer. And a few FT8 as well. Very short DX . NVIS does work most of the time and at solar min . That's why the military has frequencies in HF set aside for them. 73

[@TheSmokinApe]

Hey Robert, thanks for watching 👍

[@AndrewCCM]

Love it. Was just thinking about searching out a vid on this very subject... Yours popped up by telepathy... :)

[@TheSmokinApe]

Glad it was helpful!

[@pauldenisowski]

Very interesting presentation of this material - looking forward to future videos.

[@TheSmokinApe]

@@pauldenisowski thanks Paul, glad you liked it 👍

[@wildbill1]

Great explanation on NVIS

[@TheSmokinApe]

Thanks Bill 👍

[@keithtreisch6890]

My 40m ocfd does good. Dx and nvis. Lately been experiencing a loss of nvis when the trmperatruee dropped this past week. At night my buddy and i lose contact in the evening time . Been fun expeurencing the change if propogation around the country on different vands.

[@TheSmokinApe]

It’s probably propagation changing 👍

[@hikingfish3]

This video made me subscribe. Great explanation! Would love to see a follow up with actual antenna setups and maybe showing a qso map to prove where all the contacts were made. Would be great!

[@TheSmokinApe]

Glad you liked it HF3, I can see what I can do about the antenna 👍

[@JeffreyWilliams-x4x]

Thank you thank you Chrystal clear thank you 73

[@TheSmokinApe]

You are welcome! Glad you found it helpful. 👍

[@45auto]

Thanks for mentioning the height of the reflector being just above ground. I've had a copy of a similar graph for some time, but it doesn't specify that distance off the ground.

[@TheSmokinApe]

You're welcome, glad it helped! 👍

[@BBaldwin]

NVIS is something that has interested me for some time now, but as you stated, ya gotta have a dancing partner to make it work!

[@TheSmokinApe]

It's pretty cool though, right?

[@deirdre_anne]

The information about a reflector is very useful. I have a CF dipole that, due to my location, can't get much about 15-20 feet (and is between two houses, so it doesn't have a view of the horizon, and I've noticed it works OK for DX but also sometimes for NVIS (I mainly know from 40m nets). However, I do not have a reflector. I may see about installing a reflector to see how that affects my communications. Thanks.

[@TheSmokinApe]

Good luck with it and thanks for watching 👍

[@donausmus4281]

Ape, unless I missed it, you didn't explain the critical frequency and its more direct effect on NVIS. Although MUF and CF are related, CF is a more precise measurement and readily available on VOACAP. Of course, the 75-90 degree propagation is best close to or just below the CF. MUF is much more imprecise and subjective, involving transmit and receive locations. I appreciate your work and all your videos. Don K1DLA

[@TheSmokinApe]

Fair point, thanks Don 👍

[@VP2EIHonAnguillaIsland]

Good stuff tnx for sharing.. 73 🎙Ira

[@TheSmokinApe]

@@VP2EIHonAnguillaIsland Glad you liked it 👍

[@cynnahunter7516]

love you and your videos, but can't get on board with joining the ARRL...

[@TheSmokinApe]

I’m a fan but I totally understand 👍

[@Siskiyous6]

NVIS is plan B when the new antenna doesn't work DX

[@AndrewCCM]

Or RMA... ;)

[@TheSmokinApe]

Haha!

[@briansalsbery9968]

Is a 40m EFHW in POTA sloper or inverted V config going to behave more like an NVIS antenna? If so, this could explain why 40m is relatively useless for Seattle area POTA since the 400-mile sweet spot is mostly uninhabited whereas it cuts through huge population centers for east coast POTA activators.

[@TheSmokinApe]

For NVIS to work correctly both stations need to have an antenna mounted in a low configuration, you want the gain pointing up 👆

[@dangerwillrobinson23]

Thank you for the video. The low band EFHW antennas where one end is thrown up in a tree and the inverted vee dipole antennas supported by a mast for SOTA/POTA activations, are they working by NVIS? Or, is it skywave propagation, only compromised, because a lot of the radiation is working like an NVIS antenna?

[@TheSmokinApe]

If they are very low to the ground you will do better with NVIS but remember frequency is important 👍

[@AndrewCCM]

Stupid question... For the reflector in the last slide, would that just be another strand of wire (provided that your dipole is the same)? Just getting started here, but dove in the deep end over the past 6 weeks... LOL. Thanks in advance

[@TheSmokinApe]

Yep same wire, just a different strand 👍

[@BobBob-il2ku]

How reliable will NVIS be if both stations are using dipoles at the correct heights. & using digital modes js8call/VARAC ect? I know it will depend on time of day/year ect but can you expect to make contact 90% of the time?

[@TheSmokinApe]

Not very, in the far field plots you can see the gain radiation patterns, both antennas should be mounted in an NVIS configuration 👍

[@webanon]

Great work, Ape! Topic adjacent/aligned. Viewers might be interested in “The HF Renaissance in the US Army” on the Radio Club of America Channel kzbin.info/www/bejne/b4Kslnpqgc55g8k Start around 24:30. Interestingly, they were able to COMM at very low power levels and their watchdog technology wasn’t able to DF at those levels. TL;DR: In OPSEC plan, use minimum power needed for establishing NVIS COMMS or the watchdog tech will find you…

[@TheSmokinApe]

Thanks for the link WA 👍

[@Ramjet7777]

11:10 Point 15% 😂 I got what you meant though lol

[@TheSmokinApe]

D’oh! Good catch 👍