Hear what NVIS sounds like from 3 locations | K7SW Ham Radio
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- Опубликовано: 14 июн 2024
- Knowing what NVIS antenna to use for your location is important to
building a successful setup to make local HF contacts.
Experimenting with more than one antenna can help you build that successful setup.
3 operators will setup in different locations and different radios as "Portable" operators, to see if we can make NVIS contacts.
Using my affiliate links in this description to purchase items seen in this video, costs you nothing more and helps to earn a small commission for the channel that supports making more Videos like this.
geni.us/LEFS8010 LEFS 8010 EndFed Sloper
geni.us/hpdb CHA F-LOOP 3.0 -
geni.us/se8AX3Q BUDDIPOLE Antennas
00:00 Begin
00:30 The plan
02:00 Trying 40m with N7GPG and KB7JSW
04:08 Advantages and Disadvantages of these antennas
06:16 More test on 80 meters
07:30 Keith's Antenna setup
09:07 KI7WJP Eric Joins the Group as the 3rd station.
11:53 Eric's NVIS Station
15:18 Testing on 40 meters with KI7WJP
16:35 My opinions about our tests
🔹 MUSIC FOR THIS VIDEO: Artlist.io
When was the last time you tried setting up your portable Antenna's for NVIS and How did it go ?
Sorry if my question about the mag-loop came across as a know-it-all, that was certainly not my intention.
It was an honest question from a guy studying for his HAM exams.
So the answer is never.
But now as I think on it my Army brothers and there newer vehicle mounted tandem loop is not angularly adjusted yet they manage to get it done.
Again, thank you kindly.
Several years ago I was trying to talk to a new ham I had help get licensed and on the air. He had a 40 meter antenna and I had a 40 meter dipole about 50 or so feet high. We were about 20 to 30 miles apart. Signals on 40 were not very good. The next day I strung out another 40 meter dipole no more than 4 or 5 feet above the ground. That made a big difference. He could not get over the fact my very low dipole did so well. I took the opportunity to explain that the low dipole was radiating mostly straight up while the higher dipole tended to have a null straight up if it was close to a half wave high. Also almost all normal 80 meter horizontal antennas are radiating mostly straight up because a half wave is 130 feet and most of us can’t get past 60 feet or 1/4 wave high. Of course you must be below the critical frequency or nothing comes back down. There are some good web sights where you can get real-time critical frequency info. Check this out this station near me : www.ngdc.noaa.gov/stp/IONO/rt-iono/latest/WP937.png
Several years back I wanted to check in to the EPA section daily traffic net on 75 meters. I had a little TenTec mobile in the car with a Hustler 75 meter loaded whip on the back of the Buick. No joy from my QTH near Harrisburg to the Philly area, about a hundred miles. I loosened the ball mount for the whip, rotated it to be parallel with the ground about 2 1/2 feet above the dirt (not a favorable operating position for a mobile antenna, hi hi, but I was stopped well off the road). The noise dropped to near zero and the net was clearly heard; I checked in with a "weak but readable" signal report. The difference was no comms versus no fade, clear comms on 75 phone at 100 miles. I became a believer after that. DE KB3JA
We test NVIS once a week here in Hawaii. We have an ARES HF net weekly.
@Gary Landers Thanks for the question and sharing
I don't know anything about this - but I can't stop watching. :)
Much credit belongs good sir for your wisdom.
I love running NVIS - for lazy POTA or for in state QSO parties.
Steve, your making me want to go setup an antenna right now.
@@hamradiowithkevin Like I really needed to twist your arm...
😇
I'm building an antenna right now. Four element six meter qubical quad. I think what you did was great. Let's face it all we have left are antennas.
We use an end-fed on 40m and 80m NVIS each year when passing health-and-welfare traffic from the Gifford-Pinchot National Forest during the Bigfoot 200 Ultra Marathon. We are passing traffic using Winlink. We're often sending to gateway stations within 100 miles.
Is that with W7RAG?
This is by far the best NVIS demonstration I’ve seen. I learned quite a lot here watching this. I only have my tech license now for only a couple months but vhf, uhf, and 10m doesn’t interest me too much because of our uneven terrain, mountain ranges and so forth. NVIS coms is what interests me and for distances of up to 500 miles on HF in my area. I’ll be taking my two tests for general and extra this fall when I get some time to study up a bit. I’ve built a few antenna for my truck and also for my base station for more local contacts but Alaska is so big that NVIS makes a whole lotta sense. Gonna shoot ya a subscribe
Thank you for the support. I'm glad this video was helpful 73
I like your cooperative antenna testing! I use a non resonant end-fed stealth sloper 71' long, with 50' coax, 9:1 unun, no counterpoise, & common mode choke on a jumper 3' from transceiver. Antenna slopes down from a 15' balcony to a 6' wooden fence. SWR is 1:2 to 1 or less on 20, 17, 15, 12, 10 meters with no antenna tuner. Using internal ATU in my XPA125B amp, SWR is 1.5 to 1 or less on 160, 75/80, 60, 40, 30. Have made contacts on all HF bands. Get good signal reports on daily 80 & 40 SSB phone nets including stations that are 5-20 miles away. From California have also worked Europe, Mediterranean, Africa, South America, Australia & Asia both QRP & 100 watts SSB. It's great to have an inexpensive, limited space, all band HF antenna. I hope this is helpful.
Excellent description of your setup, thank you for sharing.
Good test to demonstrate the possibilities of NVIS for local area comms.... NVIS communications on HF ham gear play a role in a new post-apocalyptic fiction adventure series, where i have a scriptwriter role...and i am glad the ham radio portable operation fun days in my youth are being put to good use now.
Thank you, abd yes, today is always a great day to start using those skills 😉
@@hamradiowithkevin thanks... tropical expat gringo regards from Caracas Venezuela Have a fantastic finish for 2022, if you can !
One strength of the end-fed is that if you are heading to a location with suitable trees, you will have less to carry than with the other antennas; all you need is the antenna itself and likely a bit of paracord or the like to get the length right. That's great for SOTA.
I like DL2MAN's u01 antenna for NVIS. Only one 30' mast and work 40-60-80. It is like a linked dipole. You have to change the jumper to switch band but it is all a minimalist setup with good results I think.
Operating a NVIS COMM at QRP power (under 20W SSB) is VERY good!!! In my book this is a success! Remember that depending of the maximum NVIS frequency used - the Ionosphere will absorb a % of the RF radiation!
These are really good points you make. We could have consulted the MUF and used higher power to have seen increased results.
For 5 to 10 watts we were all using during the day, we really had a good outcome.
Awesome real world testing.
I agree, it looked like the end fed antenna was the clear winner.
About 12 years ago I was living in Provo. The local club I was in did something very similar to help out the Utah County sheriff's department in testing HF for emergencies. I was stationed up left fork Hobble Creek canyon in a very narrow canyon. Others were through Utah county. It was very successful on 80, 60 and 40 meters.
Very interesting David, indeed these tests are good to make sure our portable stations are setup in a reliable way. Nice work on your exercise.
I heard from old timer, before 144MHz/ repeaters become popular , people used to use 3.8MHz to do communication 200, 300 miles. they said they used to talk from Cache County to Salt Lake Valley over mountain any day just fine. AG6JU
Great Job as usual. Seeing you smile tells everyone that have found your RUclips calling 🍸
Thanks Peter, I believe I have seen you smiling recently as well 😉. It IS a good thing when we help others.
Kevin - an awesome antenna test video.....that´s the way i like to see it when a few good operators make such extensive tests! Your radiofriends are the perfect "crew" to make such experiments! Thanks for the video - love it - and all thumbs up! 73 Mike DO1MDE
Thanks Michael, your feedback let's me know that these projects are useful and maybe even helpful, These videos can be fairly complicated to produce.. 73 Kevin
Very nice video. Good to see someone actually operating (and not 'just' POTA -- Don't get me wrong, I like POTA and work a fair amount of it) with the video focused on a specific topic. Good job.
Howie WA3MCK - we’ll done sir!
In this solar cycle 40m goes way to long for nvis usually, in my experience. 80m with a low dipole or endfed works almost every time. Especially with digital modes.
I home made a end fed for 80 and it works well. I’m in Brooklyn nyc and I only have 100 by 28 space of property
Nice demonstration of NVIS. I was a member of Ogden when I was living in Utah and upgraded to K7TH. 73, Gary
Thanks Gary, 73 Kevin
Nice work, Kevin! This video is excellent. It was a lot of fun to be part of this exercise. I think that it would be fun to have more local operators practicing NVIS. This is one of my favorite uses of HF radio.- KI7WJP, Eric
Thanks Eric for helping make this project possible and doing all the work you did. Your setup was a real testament to having a solid working NVIS setup. It is so much fun working with you on these videos.
Really interesting. Im quite new to this and only have an alex loop running an IC705. I love the loop, I use it indoors and get out quite well on 10w. Hit Austrailia on FT8 from UK and can easily hit spain and italy on phone. Im looking to expand my antennas, so this has been quite informative 👍
Great video Kevin, love everything, and also the b-roll 👍🏼
Thank you Manu, I appreciate you man ! It is fun to create a project like this. 😎
I have gotten from north of the phoenix metro area to the hill country nw of austin and from the hiil country to cottonwood and phoenix.
When you showdd the maps, i realized that you were in the salt lake area. I am in the are on 7/5 and 7/6/23.
Good testing. I love the set up and how you ran the tests. Thank you for posting this.
Great video! Thanks so much!
I put together an inverted "V" antenna for 40 meters using some old wire I had lying around, a BNC to banana plug connector, a broken fiberglass mast, some RG58 coax and some cordage. The apex is about 20-25ft high, the RG58 with BNC connector runs down the pole. I hit the jackpot with the wire lengths. They needed no adjusting. At the base I made an air choke. I have practically full bandwidth on 40 meters with an SWR of less than 1.8:1 without using any "tuner" or matching device. The antenna functions very well as an NVIS antenna. I would not take it portable, however. As the sayiing goes, never touch a running system!
I never thought to try my loop, with my small yard and some interfering structures I have a 73' end fed inverted V at 30' apex and run 80,60,40 nets each month in NTX and OK with guys in my church group. I've tried running wires over fences and between houses at the 15-20' recommended height and it just didn't work for me DX engineering NVIS dual dipole, 80m 1/2 wave dipole at 6ft, 73 ft end fed flat top at 20feet, to no avail. I just ordered the CHA NVIS antenna that is on sale now and looking forward to trying that one but it needs more room than my yard provides. I need to take the jeep out and try all my NVIS antennas without obstructions and in recommended configurations. I really enjoy the challenge and fun of NVIS. Great video!
Fun adventures ahead for you. Getting out and setting up is a great thing, indeed.
This video earned my subscription. Nice work! I really likes the quick side by side comparison. Thanks for taking the time to produce this video.
Your welcome, it was indeed a project, and I am happy that so many are enjoying it
Thank you for taking the time to post these results.
My pleasure!
On 80m the Loop is a big compromise, it's never going to be very effective on 80m or even 40m Best 20-10m.
The EFHW 49:1 is half wave on 80m so offers a huge advantage over the loop.
My version of this EFHW 49:1 has a ceramic capacitor in the middle which increases resonance in the phone portion of 80m, without it resonance would be around 3.5 Mhz, the capacitor is a neat trick because it electrically shortens the antenna without having to shorten it which messes up the other bands.
I get good DX and NVIS with this antenna in an INV L kind of config, first half of the antenna is up around 60-70 feet, runs East/West and the other half slops North/South direction and I have the UNUN around 3 feet off the ground where I have it grounded.
This antenna works amazingly well for me.
All the multiple perspective video was fantastic. Thanks for this! I'm trying to hone a 40 meter and 80 meter portable 5w setup with endfed NVIS.
Awesome video. Editing is top notch. It was a pleasure to watch this. 73
Thank you very much! that means a lot. It was a ton of work but so worth it.
This is a good test reference. Thank you for this 73.
You're welcome!
Fantastic video! The Chameleon EmComm2 QRP edition was one of the main antennas that went into the valley of Turk Mountain in Shenandoah National Park last summer on a club hiking trip (bought it just in time for testing on the trip). The sloper configuration was fantastic for both getting us voice comms on 60 meters back to my local club during a weekend "Shack Day". We were also able to make a few DX contacts to a Curacao contest station and to Spain. Worked very well for Winlink also. 20 watts was the highest power used on a Xiegu X108G. We also brought speaker wire antennas, the Packtenna 9:1 random wire and the KM4ACK EFHW. All of them fared very well and survived the trip.
It sounds like you also enjoy getting out and making contacts, enjoying and using the fun gear you have. Thanks for sharing
terrific job my friend thanks for experimenting with different antennas Great job 10/10 perfect 73
Thanks 👍
Thank you for sharing those excellent videos
Your welcome Paul, glad you like them!
Thanks for posting this. Good to see some field tests. Useful to know how to do this.
Glad you enjoyed it
NVIS is a fascinating practice to experiment with. I've had NVIS antennas work just as they are supposed to, but I've also worked DX
Hi Kevin .... outstanding comparison Sir! I was just at the HRCC campout in Ramona, CA and setup a KK6USY style Delta loop and compared it to a 40 meter vertical EFHW. I was on 40 meters mid day and the Delta loop was at least 2-3 S units stronger than the EFHW receiving stations about 400 miles away. On 20 meters, the EFHW was about 2-3 S units over the Delta loop, but, I was receiving stations over 2,000 miles away at that time. As Hollywood states below, using the right tool for the job makes all the difference. Keep up the great videos Sir!
73 - KF6IF
Your test sounds like tons of fun. And Ramona, my old stomping grounds. 💪👍
@@hamradiowithkevin I saw that your roots are still in Ramona! I am bummed I missed you out at Quartzfest.
Try dropping the height of your EFHW to about 15'. I have a 80M EFHW about 13 feet off the ground along the top of some bushes in the back yard, ... works pretty good. I would also like to see the group test with the Military style NVIS 80M/40M double dipole. N1NVK
horizontal loop would be the ticket for NVIS... or a semi-delta.
Thanks for this video. Working up a plan with a friend to try NVIS here in Arizona.
Perfect, glad you are going to try it.
Thanks for this test!!! So far all three of my antennas are EFHW 40-17, but I remember the 80M later morning or early afternoon contacts I had in 1979 as a Novice with a 90' long-wire antenna and an MFJ-901 antenna tuner. Those were the days of slow speed code for me and a lot of patient older Elmers long gone SKs, lol. -Dave - KU9L
This was a really fun test, your setup is exactly the kind of thing fun times are made of. Your right too many SK's these days. Thanks Dave. 73
Awesome job with this video!
Thank you Ape! It was a project for sure, I learned how to make it even better next time
Great video, and yes, I will be trying this out in the very near future.
I have a Chameleon Emcomm III but it's only up about 25 feet or so. When I tried 160m when I first got it, I was only able to contact someone in my town. That got me thinking how useful NVIS can be. Your video is helpful. If nothing else, I will want to nail down which antenna to use and which direction(s) work to reach my friends at their QTH.
Thanks Brian, I am glad that this was helpful to you .
Great info! I have talked all over my state on 80 meters with NVIS.
I would like to try this experiment for closer contacts.
Great job on testing and editing this all together. Thanks and 73, de N4WLC Bill
Glad you enjoyed it, Thanks Bill. It was certainly a big editing project and so worth it.
We never really understand what the person on the other ends hears.
Might want to consider 60m too.
This is such an awesome video! I'm a really new ham and this is one thing I am really interested in. I would like to do stuff like this at 100-200 miles. Thanks for your work on the video.
Thank you Kevin, I am glad you enjoyed this. Welcome to the hobby. You will have so many opportunities to do things like this. Give POTA a try, POTA is amazing way try out different configurations and learn radio operation.
Oh, I think you’ll like NVIS. Reliable comms without consideration for terrain features out to ~300 miles. Use 80m during the day, and 40m near dawn and dusk.
Buy a 30 ft JackKite telescoping fiberglass pole. Set up 40m of wire for an EFHW. Raise the pole in the wire center for an inverted V configuration. You’ll be able to use 80m, 40m, 20m, 15m and maybe 10m without anything additional, NVIS and DX.
Thanks that was interesting
Glad you enjoyed it
Best antenna is a dipole tuned at NVIS height, a shallow inverted V
Hi Kevin, I recently tested a 40m center-fed inverted-V, center insulator on a 23' painter's pole off the pickup's hitch receiver, and ropes on the the ends tied off to a split rail fence, at Camp Floyd Pony Express Park in Fairfield. It made a sensational NVIS setup. I tested during the Beehive Utah Net, and heard all 150 stations well. I want to do more testing at varying heights to find the sweet spot between high angle and low ground losses.
Paul, that sounds like an excellent setup and test. What a fun project to put together. Testing like you are doing, is a really fun part of this hobby for me also. I hope to work you sometime. 73
Is it not amazing how may of use use Yeasu FT's for servial comms yet Yeasu have discontinued this excellent radios except for the FT-818?
WOW, this video may have help me with at least a question about transmitting in a mountainous area. I live in eastern Kentucky and will be setting a station in my house with ridge tops all around. It will be nice to experiment with what I have available. Thank you for this video. Will be on the air in a week or two. 73, KN4OTZ.
Glad it was helpful Jeffrey, get out there and set that up ! 73
@@hamradiowithkevin GOOD NEWS, yesterday I set up an Chameleon EMCOMM II. One end at about 15 ft., the other about 10 ft. Made my first contact on HAM radio to WV1W in Connecticut at 3:20 pm. I live in Booneville, Ky. He told me my signal was 5x5. The rig I was using is the Yaesu FT-991. I wasn't sure I would be able to make contacts as there are ridge tops all around my house. I'm glad I came across your video. SUCCESS! Thank you so much for the information provided in this video. Hope you has a Happy Thanksgiving day. 73, KN4OTZ.
Since the magnetic loop is designed to do DX from 3-6 feet off the ground, the takeoff angle is obviously going to be wrong for NVIS at that same height.
That is right. there were plenty of scenarios we did not get to try that day which could have confirmed a lot. It would be nice to try more configurations next time.
Great Video,
On your next testing, please try the loop in a ''nvis config.'' it will have better results when the loop is placed in a horizontal axis so it will shoot up its signal and will also not be directional.
but always, in general: low to the ground is mandatory for horizontal antennas as well as utilizing the MUF/time factor.
73s
according to an old article from W4RNL (SK) Cebik....that there will be some directionality due to voltage peaks on the element.
I'm afraid you misunderstand that antenna. The small loops are directional in the plane of the loop, not broadside. There is a very sharp null in a roughly 15º cone on each "axle" of the "wheel." Putting it horizontal sharply nulls anything going straight up, and also requires elevation above ground to avoid excessive losses, just like a dipole.
@@paulplack490 Thank you for enlightening. I witnessed one tune up on 40m and it had some problems, and in fine tuning it as well. Of course, there are many factors in place but after putting the wheel in horizontal position, the local contacts started hearing us with full saturation. it was the only ant. to rival my AS2259/GR as we had portable SSB setup. I'm assuming we had optimal sub ground structure as well. the height was about 2metes above ground and 6meters for the crossed dipole.
@@W8RIT1 Thank you, I will read up about it ASAP.
I don’t like magnetic loops. The big issue is that they’re mostly power limited. A loop that can actually run more than QRP typically need vacuum caps, so tends to be bulky and relatively delicate.
The only advantage to magnetic loop is if there are very strong neighboring transmitters saturating your receiver. The very small bandwidth can prevent those signals from reaching the frontend in the first place.
I’ve found the most practical, robust and easily portable antenna for NVIS is the EFHW. Carry a 20ft telescoping crappie fishing pole, or better a 30ft JackKite, and you won’t need trees. Set up for inverted V with the pole holding up the center.
End fed long wire is the way to go if you have the space. I use one 400' long at the home QTH. The trick is to match the TX to the EFLW or end fed long wire. Not trying to work locals though
Very nice experiment. Looks like the endfed is a big winner on 80m. That makes me happy as I have one of those. But since I’m a renter, I can only deploy that if I go to a park or something. I use a 40 endfed at home. Very stealthy. 1st qso on that was on 40 m from South Dakota to Spain. Yeah I’m sold. Both. Were MFJ antennas. MFJ-1984 & MFJ-1982. I also have a qrp endfed kit by k6ark that is superior to the mfj’s.
My HF antenna at my QTH is a Alpha-Delta DXCC multiband dipole set up as an inverted-V. Apex is about 25-30 feet up, ends are 8 feet. It seems that the pattern is fairly omnidirectional
Great video Kevin. I am guessing the station with the poorest comms in this test was the one closest to you? It's been my experience that for reliable NVIS comms the distance between stations usually needs to be about 30 miles or more. The angle is too steep "straight up" and will just be obsorbed, and won't reflect much if at all. The solution for local comms is having a network of overlaping NVIS stations. You can use voice to relay but the most efficient way would be digital. KJ4LG
Thanks Mike, I appreciate that. Kevin
Since your end fed was 25' in the air, it would have been interesting to put a reflective element under it to enhance the vertical part of your signal. VE3MCF & AK4HB
indeed, If we had more time I would have also lowered the antenna and tested different heights. so many tests to run and so little time that day. More to come :)
Loved the video. It was a great demonstration of different radios and antennas. What time of day where you operating?
Thanks David.
We did this test about 2pm in the afternoon.
@@hamradiowithkevin 2pm in the afternoon… that is amazing! I always considered 80 meters as the night-time band and never used it during the day. The signals you were experiencing in the middle of the day were so clear and impressive for such low power. I was very impressed with the video and just how well NVIS works. It really is something every ham needs to know how to do, especially to be prepared for an emergency. Thanks again for your video.
An excellent real-world test, thanks! I appreciate the mag-loop tests especially as I plan to build one soon. As I watched the video I kept wondering if it would work NVIS better if it were positioned horizontally to the ground, or would that require it to be a certain fraction of lambda over the ground to avoid ground absorption effects? Also, as one or two people have noted in the comments, the FCC does require you to be a certain distance away from a mag-loop for RF safety reasons, but IIRC that distance is 3 meters when transmitting 100 watts. QRP levels are much lower so you could position it within arm's length or even use it inodors with no problem.
Your welcome, glad that you enjoyed it. From talking to Chameleon antenna, they said being horizontal would have a minimal effect. I should have noted in the video that I was running 10 watts. The loop that I was using can only handle 25 watts maximum. Reading the FCC radiation exposure guide is always a good thing to do, exposure levels can very from operation to operation.
I like your channel. Lots of good info. So, for NVIS, it is very frequency specific. You are trying to bounce your signal off the F layer of the atmosphere. It makes more sense to me that it would work better in the 60M to 80M band. Also, for antennas, a dipole about 10ft off the ground would probably work the best. I would not expect the Loop to be any good at NVIS. Although it would be interesting to raise the loop up 10ft off the ground and see how it performs. 73.
Thank you for the video. Were the antennas setup any different for NVIS ?
Next time we do this test, we will try ant different heights. This time we just setup one way and then did our best to make contact with each other
I think many people don't realise that just putting up an nvis friendly antenna will not make nvis work. The ionosphere has to be in the correct state as well. Specifically the "critical frequency" aka FoF2 has to be higher than the frequency in use. In theory it can go up as high as 10MHz but normally it sits somewhere around 4 or 5 MHz. I suspect that was the case during these tests and the reason why you had success on 80m where you were using NVIS and 40m where you were relying upon ground wave.
73 Ed DD5LP
Man, I would LOVE to get in on this action! Shoot me a note next time you guys do a test like this. My 80 Meter antenna at the home QTH is pretty much NVIS (only up about 18' off the ground). And yes, I'll pick up the mic to help with the test... ;-) DE K7RLN
Hey Ralph, I would enjoy having you in on one of these adventures. I am already thinking of some followup videos. I can certainly envision a winter setup happening . Kevin
I like this. I’ve been working to figure out how to hit the house from where I work 41 miles away as the crow flies. Looking at topographical maps, you’d think a 50’ tower at the house would clear the land features, but once I calculated in the curvature of the earth, I now need a 1,200 foot tower at the house for LOS on 2m. So I’m switching over to the HF and NVIS as a possible solution now that I have my General. I’m curious if we can do NVIS on 6m since my wife is only a Tech. 🤔
If you are talking about 2 meters, I have a 40 foot pole with a dual band Vertical at the top and I can easily contact operators 60 miles away. There is usually no line of sight, but the signals often bounce off the mountains in our area. Get a good antenna for your wife and a good antenna for you. Park at the highest points that you can and you will be good. Use a mobile radio and not an HT and your results should be acceptable. Hope this helps.
Great experiments! I saw a comment that said most hams 75m dipoles are nvis because we can not get them up a half wave. I have often said this myself. Lots of nets on 75m have nvis stations checking in by default lol. 60m is also interesting with NVIS. Have yet to test 40m nvis. I may be wrong but I believe your mag loop would be vertical polarized? Would a mag loop be able to work nvis or only groundwave/skywave? And for hams new to nvis frequcies higher than around 40m are usually not reflected back down so well. You will usually see nvis used with bands from 40m-160m. For example Nvis with vhf (2m) is not going to work because it will pass through the ionosphere. Great video! Thanks for sharing!!!
Yes you mentioned many things that are just true. It is nice to hear that someone else is trying to have a purposeful NVIS antenna. Thanks for sharing what you have discovered. I really think it helps all of us to share our wins and the fun.
Tank you, this was a very interesting example of NVIS comms.
I have a couple of questions if I may?
1. Your brother HAM who was using the home brew antenna with a DIY adjustable ferrite choke, was his wire antenna in a end-fed configuration or OCFD?
I noticed his feed point was at the lowest point of the droop.
Also which of the call signs were his, N7GPG, KB7JSW or KI7WJP?
Last but not least.
On the use of a small mag-loop for NVIS, where as the maximum signal strength is in the plane of the loop (which includes the top of the loop) I'm wondering if it wouldn't have worked better if you had the mag-loop tilted 10 or 20° towards your intended recipients?
Thanks again for taking the time to make these videos.
Gary
Gary, KB7JSW had the adjustable choke endfed wire antenna, at a few points in the video, I was able to rotate the loop and improve the signal both for 80 and 40 meter contacts. you would have look back through the video to find those moments however.
I appreciate you asking.
73 Kevin
I have Inverted L Antenna, 24 FT high 30 ft wide in Orange County CA , height makes it more of NVIS antenna for 3.5MHz, 7.0 MHz band. I can communicate well within 1000 miles or so. all the way up to Washington State, Arizona. I often do much better for path along coast line from Orange County CA to coastal Washington State, over toward inland like Texas. AG6JU
Hidenori, you have described a really nice setup. I bet it works great. thank you for sharing.
Great video. What was your end-fed antenna orientation in relation to the other stations?
Thanks, we had our wire antennas strung out North, South If we had more time that day, it certainly would have been good to move the antenna orientations around.
Great demo and test, what about after sunset?
Dave, I had only a short QSO with N7GPG at night from my Trailer and used the same antenna. He was using 1w and had a HUGE signal. , just never made it into this video. This was so fu, that next time I will make sure we do some night time tests for the video, thanks for the suggestion. 73
Great demo. What were the distances between the stations? 60 meters is often right at the sweet spot for NVIS.
With more planning, we could have tried more bands. Check out the section in the video where I show the distances. 17, 25 and 30 miles I beleive. Thanks for asking, 73.
The magnetic loop is hopelessly too inefficient on 3.7 MHz to even bother with. I have many mag loops, but I only use them on 14 - 30 Mhz......preferably on 15/12/and 10 meters. A simple piece of wire thrown into a tree would whip the mag loop on 80 and 40. Thanks Kevin, fun experimenting
Thanks John, it is good to hear some mag loop experience like you shared. This is very helpful, not many hams have tried or experienced the loop. 73
I suspect for where you were within the issues of static within 1-8MHz, I would try something within 21-30MHz to see if that improves your transmission ..
you have heard pushing shit up hill ??
I think you are okay at reception however on transmission you are hitting the peaks you are likely looking at 40-80 foot antenna with the co-ax placed in a metal tube so the only in transmission is the antenna and that's it..
im new to your channel .i saw your last video on ant testing in the park near some tennis courts.. thus NVIS i need ask please ,ive seen YT on these but they use a 1m off ground reflector underneath horisontan wire..woulnd that be better. i have a few efhw etc and long wires..is it worth the extra work to put reflector under ?
Personally, I would not use a Reflector for your setup.
Don't let that keep you from experimenting though.
Did you check how was the FoF2 measures that day on the test to determine the optimal frequency for NVIS.? It seems was better for 80M that seems that the FoF2 at that time was maybe 5mhz as maximum frequency.
It is on the list to note the MUF and a number of other details that we did not get this time. We were virtuous on this trip. Thanks for the good question
@@hamradiowithkevin It was an excelent video testing the NVIS. Very complete on testing the antennas. The results I have had is the end fed is the go because is tx stronger, but for Rx a lower dipole is better. I would recommend the same test replacing the worst antenna in the test with a Dx engineering design antenna that is a cross dipole. It is short but it works very good for smaller spaces. This dipole have four branches instead two. I had many good results some years ago doing different NVIS test.
73
HP1GDS
Nvis try horizontal loop should not be rotating vertical loop in direction of contact should be aimed up
Ground waves
I get a kick out of folks carrying batteries and solar panels around when they have a 50 amp 12 volt generator behind them in the vehicle.
Often times a vehicle, which includes mine, which produces a lot of alternator noise that really interferes with radio operation. For me a generator is too much work to operate with.
Wire antennas will ALWAYS be preferable for NVIS than anything else BUT they CAN'T always be deployed due to environment constraints, time, manpower or or weather issues!
I'd be interested in the results if you flipped the loop horizontal.
Ed, I wondered the same thing. I contacted Chameleon before the test, asking the same question and they told me it would not make a noticeable difference.
May I ask what mast were you using for the EFHW and how was it attached to your trailer? Possible subject for a short?
Great question, thanks for being here. This specific mast is a used window washer pole that can reach up over 40' I will have some mast v setup videos in the very near future, thanks for the suggestion.
Never tried NVIS, always wanted to though.
I am curious about your experience with solar charge controllers and maybe inverters while operating from a low noise environment. Which have been low noise and which have not? The tests of antennas and NVIS between parties was very interesting and I enjoyed this video. 73 W4POT
Thanks Ed, over this summer with all my activating outside the RV with my little panels, I really never had any noise issues. However, operating from in my RV with all the electronics, WOW what a nightmare it can be. So i really only operate in the RV at night. it so much more fun to work the radio outside at camp anyway, at least when it is warm. 73
@@hamradiowithkevin is that due to inverter use? Trying to compile a list of noisy vs. clean items since the data is missing from most general consumer reviews. 73
@@EdwardGriffin , there are so many things making electrical noise. It never ends trying to silence them all, so I just find ways to use the radio when it is more quiet
Would horizontal full-wave loop, square or delta, at about six feet agl work as a cloud warmer on most any HF band? It's seems the higher the frequency the farther the contacts. Please advise.
Yes, lower to the ground for 80 and 40 meters will be ideal for NVIS. Other bands will not be very good for NVIS
Do you have any concerns about RF Radiation with the loop antenna so close to your operating station?
Thanks for asking. Not at the 10 watts I was operating at that day. Since then the remote tuner has come out which mean the antenna can be 20 feet or more away from the radio. And that is a good addition
Wire usually wins at 25ft. Is that choke necessary on the efhw? I thought they wanted at least 25ft to work off being the ground side and all.
I agree, wire performs well in most situations. In this case, the Chameleon LEFS-8010 manual suggests using the Chokw at the feed point. I have tried both at the radio and at the feed point and I can say that the match is more consistent with the choke at the feed point. I tend to use different lengths of coax for each setup I am at. I would have liked more time to be able to lower that wire antenna to other heights off the ground and get those results.
Blue tape on the 857, to protect from scratches?
Amen brother, to me the blue tape is both fashionable and functional ;)
The painters tape does not leave residue when I periodically change out the tape to keep it looking fresh.
@@hamradiowithkevin Hear that. At first I thought it was a custom blue case. I've been known to leave the plastic on a new lcd for years. Lol
The guy with the 80M antenna at the park made a major installation error which will GREATLY influence the radiation pattern and the performance of the antenna thus the overall NVIS COMM experience. You CAN'T wrap a radiating wire on a post like he did! The antenna transformer which is on the table MUST be attached to the post otherwise - you'll lose a lot of power and create RX and TX issues! It will be even worst if the post contain metal inside or around!
heard some RFi noise at about 14:53....wall wart?
Hard to say. I did have some campers near our site that ran a gas generator. Good ears !
@@hamradiowithkevin I have nightmares of that sound. Ha. Mostly in my case powersupplies. Worst one was a Ubiquiti etnernet switch.
17 to 25 miles during the day on 80m? That was groundwave, not NVIS.
what model Yaesu is that? It looks like an 891, but not exactly.
That is a classic 857D 👍
thanks very much, and thanks for posting this video.@@hamradiowithkevin
Did you try any loop antenna to loop antenna communications?
How about a vertical or dipole?
Great idea for a followup video or two.
Never heard how low swr was on the loop on 80m
The loop is almost always tunable to near 1:1. That is just how they work.
In the off chance the loop is setup near a building that can cause interaction, generally, you get to tune the loop to a really good spot.
Checkout one of my loop antenna video's and it might make more sense as to what I am describing. 73
You said the end-fed antenna was up about 25 feet at the ends, and a bit less in the middle. That's probably too HIGH to be a good NVIS antenna on 40 meters; your takeoff angle was too low. It probably would have worked better at 10 feet than at 25.