Ham Radio - NVIS antennas and the Chameleon MPAS
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- Опубліковано 21 лип 2024
- Experimenting with the Chameleon MPAS in an NVIS configuration. I thought I'd talk about NVIS antennas.
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Even as an experienced ham, I enjoyed listening to your whole explanation including the introductory material. Keep doing what you know is best! You've earned a subscribe here.
Last year for the PA QSO Party, I wanted to experiment with NVIS. I put up a 60' wire endfed with a 9:1 unun. It was roughly 10' above ground level, and I used an MFJ manual tuner and 100w power. I wasn't seriously contesting, and I didn't get a clean sweep of all 67 PA Counties, but I was able to work enough (45 counties) to prove to myself that I could work any county in Pennsylvania on 40m or 80m, depending on the optimal frequencies for the time of day.
Thanks for the great video!!!
73 de W3COB
I've recently taken NVIS as a serious pursuit and I've been quite happy with what I am able to do with an Ultimax 80m-10m EFHW antenna on 80m running SSB phone at 10W and 20W. The antenna is configured as an inverted-L at about 25ft resting on the top of some trees. Beneath is a 5ft tall chainlink fence that is probably acting as a reflector.
I've done a little bit of comparison of the EFHW against my Chameleon Emcom III portable antenna on 80m. On 80m ancedotal testing suggests it is about -6dBr from the EFHW. I only have the stock single 25ft counter poise wire. There is an optional 4 wire set.
As I operate portable in parks I don't like a lot of wire on the ground so I bought two of the Super Antenna 17m, 15m, 11-12m, and 10m counterpoise sets. They seem to provide a slight improvement to both antennas. Especially to 80m and 40m on the Emcom III.
The Emcom III is my first try at a manpack portable HF antenna for my FT-857D go-kit. It wasn't my first choice, but I had a $200 Amazon card and Packtenna doesn't sell on Amazon so I thought I would give the Chameleon a try. Its performance 40m and up seems good enough to be a keeper antenna, at least until I try something better.
Hopefully I'll rack up a bunch of counties during the Florida QSO party with just a few watts.
Thank you for putting the lids in their place at the beginning of the video. I’m glad you chose to continue to explain before you show as I do not know everything about everything and I hate it when somebody start something in the middle without give me a background of what I’m Luke trying to learn. Keep up the good work
I always thought of NVIS as a propagation mode and any antenna that helps you achieve it is therefore a NVIS antenna. I use a full length 80M dipole with a feedpoint roughly 10ft above ground. I get very consistent regional (400'ish miles) coverage with stray lobes landing not so consistent long range. One long range was Alaska (I'm in SE PA). That really made my night!!!
I enjoy your content! Thanks for your videos!
73
I have the same understanding as you
I'm new to radio and appreciate that you explain thing in a way a beginner can understand but deep enough to open my eyes to what it is and does.
I'm happy to know it was helpful for you.
Very helpful info. I am new to HF. Continue ignoring the haters and keep producing these great videos. Much appreciated.
Thank you very much for this very informative Video. - I will put something like this on my flatt roof.
73 de Roman HB9XBK
The mystery language sounded like Laotian, the language spoken in the country of Laos (next to Vietnam).
Thank you for continuing to explain the basics before diving in. Your explanations are straight and to the point. I always learn something.
NVIS is a fairly new term for something that has been going on for a very long time. Using short-skip-favoring antennas on 160, 75, and 40 meters has been happening since the 1920s. In fact, it's what most stations have always done: use horizontal antennas low to the ground in terms of wavelength. On 75 meters, any horizontal wire under about 90 feet in the air is primarily an NVIS antenna. Such an antenna between 60 and 90 feet up will work the best. Below about 60 feet up (a quarter wave), efficiency goes noticeably down due to ground losses. So between 60 and 90 feet in the air is optimal for NVIS communications (though lower and more lossy antennas obviously do work). Above 110 feet up, the upward radiation starts to fall off quite significantly. Double those height figures for 160 meters, halve them for 40 meters.
A local EOC here in CT was having the same problem with HF communications you describe at the end of this video. They had originally set up the EOC with a vertical antenna due to space restrictions but found it was almost useless for local work. They then experimented with an NVIS dipole and had much better luck with local communications within their coverage area.
Your instructional approach works great for me as always. Please keep it coming as you enjoy your new nomadic lifestyle.
Guys used to have 160 loaded verticals on their vehicles, with a whip bent from front bumper to the back, and talk to locals, back before repeaters took over.
Police radios were on the low bands also for the same purpose.
Hi Keven.
Great video.
I’ve been doing a lot of reading about NVIS lately
An I appreciate the extra info.
Keep up the great work.
I’ll catch you on Callum’s show.
Very good video. I like your practical demonstration with the MPAS.
Excellant and thorough as always glad you made it up to N AZ
Thank you for your explanations, as I have always enjoy your presentation, to simply say what I mean is, you engage with people wanting to learn more which has also encouraged myself to get my licence. 73's VK4 fpkl.
Good explanation. I run the Cha Emcomm II much like this for NVIS. Good stuff.
Hey Kevin, nice vid on NVIS. I have ordered the new CHAMELEON HYBRID MINI 2.0 from Carl L., but ordered it with a 130 foot wire for NVIS , I cannot wait , thanks again
Great and informative video. Please keep these kind of videos coming.
Kevin; I am really into antennas, this was great information for me here! Thank You. Randy. California.
Thank you for the great NVIS lesson. As a 1980 novice cw operator, I did not realize my 70 foot end-fed just 12 feet in the air was NVIS at its finest. Just made the longest and highest within my means. It worked super well for any qso up to about 700 miles on 40 meter daytime. Any more than 50 watts was a rude excess to go +30dB over S9.
Thank you for the videos you post here on UA-cam. They’ve been very informative. During hurricane Michael NVIS was the primary antenna configuration used in deployments and at some emergency operation center’s (EOC). In some cases HF what’s the only means of communications. NVIS covered the entire panhandle of Florida and in some cases reached into South Florida. I wanted to pass along our experience with NVIS here in North Florida. Karl KG4HBN
What band worked best for you?
keep doing what you're doing. Not sure who's complaining. But most videos and presentations will explain stuff before they show you the actual thing they are explaining. SO keep it up its what should be done. Luv your videos.
Great to see. Not enough common discussions about NVIS. ...Thanks!
I think your research was fine and the information was also great. Working with different types of antennas is what we as amateur radio operators do, meaning we experiment on antennas of all types and we practice what knowledge we can gain from it. I learned as kid and pretty sure at some point in your lives. "The dumb question is the one question you never asked." Information is key in this field of radio communications. For what it's worth, any type of antenna we Hams may work on it alone, in a group,with a friend or more, and our radio clubs around the world. If works awesome if not we try something else that makes it work make it better. We as hams help newcomers by addressing questions and we give input on what rigs to start with in the beginning. We help our Senior hams by helping with antennas on towers, digging holes for a tower, or just sitting around and discussing anything to do with radio operators and gather information and passing it on. Don't stop helping because some people are just know it all's and no one knows everything.
You made me think about NVIS in a slightly different way, as in "how can I make use of it", thank-you for the insight.
I've heard a lot about the Chameleon MPAS on UA-cam so I checked the company Web site. The good news is that if you buy one they will give you free shipping worldwide. The bad news is that the antenna set costs $600. No matter how great it is, this is a lot of money for a wire antenna.
I prefer to hear what we're going to learn before the demo. Tell'em what you're going to tell'em, tell'em, and tell'em what you told'em. That's what you do when teaching adults.
"Well, too bad". LOL!
When he said that, I gave the video an immediate thumb's up.
Really enjoyed your Video,and the explanation at the beginning Kevin- Thankyou !
Los Angeles has several asiatic language stations and KNX 1070 is a clear channel station also out of LA. If you tuned to 640 you could probably hear KFI as well. Interesting. This came up as one of the alternate suggested channels that are on the right side of the you tube screen. Being a new ham I clicked on it. Nice to have the explanation and then the demo. It lets me know what I'm going to be listening to. I currently live in Kingman, AZ moved from Rosamond, CA after I retired. KK6LOP here.
Good Stuff Kevin, We used NVIS after Hurricane Irma even to PR, but during Hurricane Maria while on St. John USVI, we were the EOC and operated to St. Croix, St. Thomas but we lost all comms on PR after Maria came ashore.. It was a military net on 60 meters. I just cut a wire and used an IC7000, and IC AH4 turner
Maybe those not happy with the order of things, should spend 5 minutes watching a youtube video on how to watch a youtube video. Like how to advance forward by using their mouse or the right arrow keys in 10 sec. increments. I'm not always happy with how slow others speak so i've learned to use the speed adjust at 1.25x or 1.5x speed, and if I miss something I happily use the left arrow key to jump back a bit.
Keep up the great efforts.
Some of our local hams are interested in meeting on direct frequencies. We are scattered about in a 35 mile diameter or so and in the foothills of the mountains. Yesterday, in the video recommendations, I saw this one and it reminded me to consider NVIS.
My antenna is only about 12 feet on the ends with most of it running about 9 feet high. I thought it was NVIS until you said yours was only 6 feet, LOL.
We tried 40 and 80 meters, but the antennas were my dipole and Buddi Stick, an inverted V and another dipole. None of us could hear each other well. So, I'll suggest we try the NVIS.
(For those who read in the future, we are all in the COVID 19 Stay-at-home restrictions here at this time.)
Weather looks good today, so I think we can try it.
I have a chameleon emcomm3 portable running off an icom 7100 with no external amplifier. I love that antenna. 73' long and I have it 15' up running horizontal for NVIS. 40m is the clearest out of 40m, 80m, or 160m. I'm in central Indiana and I have talked to people as far away as Georgia with decent clarity. But I have heard people coast to coast, furthest has been Italy and Puerto Rico so far. Ive had it up and running now for one week. 73 all
I don't mind you talking about what you're going to talk about at the start of the video but it drives me nuts when you talk about talking about what you're going to talk about. LOL. Just kidding. NVIS is one of my favorite ham subjects. As a result I didn't learn a ton from this video because I'd already done a lot of research on my own but it was still great to have you covering NVIS and I'm very glad you made the video. It's very hilly around here and my primary interest is in talking to friends who are 100 miles away or so but without relying on a repeater so NVIS is very interesting to me. I'm also extremely interested in some of the low power digital modes like Olivia. And the WSPR beaconing is always interesting too, so I'm glad you included that in this video.
Refraction not reflection. Thanks for sharing. Never used that antenna b4. Looking good!
The antennas on the hmmwv are for the ACIP(SINCGARS) radio UHF/VHF. They are tied down so you don't tear shit up. The HF antennas most of the Army uses are twice as long.
There are a few places on line where you can get soundings that give the real-time critical frequency. They also give a chart of the MUF for various distances. If at or below the critical frequency your signal will come straight back down. At or below the critical frequency there is no skip zone. Above the critical frequency and you start to have a skip zone. There is always a skip zone on 20 meters. The only exception I ever heard about was once in 1947 and a few times in 1957 at the peak of the super sunspot cycle where the critical frequency did reach 14 MHz! There is some sporadic E skip on 20 meters that yields some very short skip with extremely strong signals but that’s not really NVIS.
Ecellent explanation, Thank you!!
Yo Kevin!:
Great video as USUAL! I am not a proponent of NVIS as I want distance generally, BUT DO understand it's usefulness just the same. I have a G5RV up about 35 feet and appreciate every foot of distance I can get. I really want to work on 160 mtrs, but have issues with my tuner that need solving. Hi.
Keep on with your style, you know my feelings about that!
73's my friend!
de seeker/Jeff WA7LFP
Great topic. Next time you are in Quartzsite, look up K1AN as he is very much interested in NVIS.
An NVIS antenna works well on 80m at night and 40m during the day. It is also great to use on 30m, 20m, and 17m when there is sporadic E nearby. The critical frequency of some of the Es can get as high as 20 MHz, so an NVIS antenna is perfect for working stations that are normally in the F-layer skip zone on 30m, 20m, and 17m.
Hi Kevin, like at 8:55 a lot of our AM broadcast stations here in Melbourne have gone over to DAB+ or FM, only for those vacated frequencies to be re-allocated as ethnic community radio stations.
Also perhaps you could explain Sporadic E propagation, or even Tropospheric Ducting to the newcomers of our wonderful hobby.
I've been confronted with multiple stations on same frequency and my 1886 listening to Radio New Zealand on 5.945 and close by same frequency. My antenna is fixed and I had to use all 4 notch filters to get copy on RNZ. RNZ uses multiple frequencies as time passes. The antenna is fixed 50 degrees East of North and the opposite if I remember correctly concerning directivity of the loop. NVIS is a great way to work the stations closer, yet not LOS. I'm really surprised by the loop configuration that has opened a lot of doors for me across the world. I live in Kansas near Kansas City in a suburb using first the SDRPlay RSP 1a, and now the RSP 2. I hear the local FAA operations along with plenty of 2 meter repeaters even repeaters some 50 miles away or better. I get plenty of South American stations on SW and Radio Havana is no problem. I also hear Italian and other languages not from the SA stations like VOA transmitting Vietnam in English through I think is re transmitted from Florida or TENN. Great stuff; these mag-loops and LNA even with overhead power lines and such. Being SWL with good antenna is satisfying knowing how much of a challenge listening can be at times. I like your channel, I'm retired as well and it is good to hear about subjects like NVIS that you bring to the table.
Hi Kevin, just decoded your WSPR signal on 40m while logged into a remote SDR at PSU in State College, PA. Call sign used on the remote end was SWL3/SDR for WSPR spots. The audio was passed to WSJT-x via "Virtual Cable" so the actual decode took place on my PC here in south Texas. 73 de N0IJK/5.
Hey that's cool. Actually testing a new antenna project I just finished up today. Two vids on this one, just getting ready to release the first.
@@loughkb Looking forward to watching them!
I live in alaska and nvis is the most useful for this area due to all the mountains. 80 meters is the most commonly used by hams up here for local comms.
Best antenna for NVIS is a dipole tuned at NVIS height, in a shallow inverted V configuration I beleve 1/4 wave above ground is closer to optimal I have good luck 100 to 471 miles from my location
Hi Kevin - interesting video. Thanks a lot. Hope the motorhoming is suiting you. I also do some ham radio from my M/H.. I have a few basic videos on my channel. I need to make more time to video, edit and show some of my /P antenna experiments. Mainly wires. I like NVIS for local comms especially our ‘Worked All Britain’ net on 80m. Cheers, Nick M1DDD
GREAT VIDEO AS USUAL .....
Yes please keep up the explanations
Thanks I found it interesting. Now I think i'll try one. Now it was well exlpained
HI have bee playing with one of these on field days mine transmitting wire7foot.3 inch,s agl one wire directly under with over run of 6ft ech end and a wire 8ft out either side works a treat long distance was from Central Coast NSW au to Sigapore on 10watts on a 120v 40m ,all home brew woth plastic conduit poles in sections for easy transport
I don't know if you were speaking with someone from Rockport or Aransas Pass, but Aransas Pass seems to have done exactly what you were suggesting. If you go the W5ICC entry on QRZ.com you'll find an explanation of what they did which included having several city staff members get amateur radio licenses and the city obtaining ham radio equipment for emergencies. They also set-up a D-Star repeater which is pretty easy to reach from Rockport.
Helpful video, thank you Kevin, 73s , KD2PHM
Great channel Kevin! keep up the good work. I have a question. Can you bend a NVIS wire in two places and still get a decent radiation pattern? I was thinking of mounting a wire under the eaves. it would be 8 feet above ground. 40 foot run then 90 degree turn to a 60 foot run then 90 degree to another 40 foot run for a total distance of of 140 feet. basically 3 sides of a rectangle. Not sure if this is worth experimenting with. Anyway thanks for all the good content!
Awesome video Kevin, makes you think how much antennas make a difference. 73's - ZS2GHK
Please explain first always. Great lecturer.
Go to wikipedia, type in "1120 AM" in the search box (no quotes). It brings up a list of all the stations on 1120 kHz. Click KZSJ. It brings up format and other info. Great tool for AM BCB DXers! Video suggestion since you have the room: Beverage Antenna. 73 de N0IJK/5.
Thanks for giving info before showing.
You can only have effective ground waves if using a vertical antenna. Ans even then you are more likely to benefit from ground reflected waves, to have any luck with ground waves you would want to be near salt water or wetlands and it also depends on frequency. I am interested in leaning more about how to get better ground reflected waves such as by using a ground shield or parasitic ground reflector which could work better than the reflection from the actual ground. Part of a ground planes job is to match the antenna but obviously radiation pattern and the reflected signal is also very important.
Most deserts are really not good for ground waves and generally anything above 1.5Mhz is not usually worth thinking about other than with amazing conductivity ground.
Very helpful
Kevin, really nice video. As always :-) NVIS is ansolutly important in an SHTF szenario. BTW. I always wonder how do you secure your shack and equipment while on the road with the RV? 73s de Stephan, DF6PA
Search for my "desk tour" video. I show the whole setup.
thanks, the ones complaining could be people who are famiiliar with topic and got sick of theory
i'm currently interested in NVIS, i saw local petrol prospecting companies using NVIS antenna around here (Algeria, Sahara desert), and we have lot of valleys and VHF woudn't reach that far.
i was curious if i could pick something so i setup a 40m inverted V, and also hopped to pick HF airband too but no luck, but picked shadwick in irland
Very intersting Thanks a lot, HB9GUR 73 qro
So is it correct to say that all dipoles are NVIS antennas because of the way they're oriented? Won't you always get skywaves with a horizontal wire?
There will always be some signal going up. By lowering the antenna closer to the ground you increase the degree of vertical radiation.
"We got the entire country" *cries in Alaskan :-)
Great video! Very interesting.
Any thoughts of using 2 40 meter hamsticks in a dipole configuration mounted on a 6’ tripod. Thinking maybe for an emergency situation if local repeaters go down, hf as an alternative.
Sure, there's even adapters made for that that I've seen. Not sure where to get them. The bandwidth will be somewhat narrow, so you'll have to retune the hamsticks if you want to go from the CW portion to the SSB portion of the band.
I am game for 80m NVIS for ARES comms. Houston local to TranStar. And so I can get into Austin.
"Envis has left the building.."
1070 is KNX in the Los Angeles market. The 1120 station is probably Vietnamese.
Do the higher frequencies just go straight threw the atmosphere? Be interesting to try moon bounce with a beam antenna in that case. I've been toying with the idea myself.
Depending on solar activity, the amount of bounceback from the higher F layers varies greatly. The solar flux number can give a good indication. When it's low, below 100, less is bounced back at higher frequencies.
I would like to know if a dipole attached to the backstays of a sailboat would work, realizing it would be an inverted V?
I've seen antennas on boats. Don't they usually put the center feed point up on the mast and bring the legs down to the ends of the boat? That seems like the best case solution to an antenna on such a craft. Provided it's oriented to keep the wires out of the way of the rigging.
But then again, I'm no sailor, so it's just a guess.
Yes it would work very well depending on the lenght you can get...The Salt Water is a great advantage being an excellent ground and reflector of the radio waves.
Best of Luck with your efforts.
NVIS, especially QRP NVIS is more difficult to locate. This was more important when HFDF was done principally from ground based systems, even so worth knowing. NVIS is principally a 10 MHz and lower propagation mode. It is unusual for higher frequencies to be reflected back to earth at near vertical incidence. One of the defining criteria is a propagation range of less than 400 miles. Otherwise it might be short range but not be NVIS. I don't think I have ever heard of exactly what the refraction angle is required to be for it to be deemed NVIS.
Hi. I just bought the Chameleon EMCOMM III. Will probably utilize as an NVIS, but in your experience, can you skip pretty far with different configurations such as an inverted ?
Just about every antenna sends RF off in all directions. Anything heading out 20 degrees or closer to the horizon will most likely skip.
Thanks for the videos! I appreciate the explanations, and I learned something. I’m curious if you are still using the MPAS antenna? 73 K7NFO
Yes I am. Although I modified the hybrid. I gutted it and replaced the transformer with a 9:1 unun. I have to use an antenna tuner with it now, but it hears much better and I get heard better.
Did you use a counterpoise for this setup? I have the same antenna with not so very good results. I'd like to Use it for nvis as well. 73s from Ohio
I'd never seen great performance with the Chameleon hybrid module. I saw a German guy's post where he'd torn it down to find a dual transformer setup inside, a 5:1 unun arrangement. He filmed it with a FLIR camera and found it was generating a lot of heat during TX.
Makes sense. In an effort to provide a sub 2:1 SWR across all the bands, compromise needs to be made. It eats some of the power.
I gutted mine and replaced the transformer with a more common 9:1 unun design and it performs much better. Although I do need to use a tuner with it on all bands now. I don't' mind the trade-off. I like the physical hardware itself.
I was using a counterpoise with it, to answer your question.
what Rig are you using in the video
Icom 705
NVIS something that would be really useful if HAMs actually did it. So is HF for that matter :)
Kevin ... just wanted to say 👋 hi!
A couple of us in Dallas, Tx view you. It occurred to me if you had a dipole about 1/8 to 1/4 above a tuned reflector, you should get 3dB going up. That’s about it. And only a part of that 3dB would bounce off and make it back ( over that mountain ) you were talking about. That’s not much at all. Are you forting in the wind or what?
why a 7300 and not ft991??
I like the user interface on the 7300 much better. The yaesu menus can be confusing.
Emergency mode Pilgrim. Tune dat baby on 160.
Add JS8CALL to the mix and you have the possibility of very low power, unattended reception of messages and relaying. WA9RYO
There are lots of folks who always know they are the smartest one in the room.
So you keep wasting a few minutes, cause it’s a good teaching practice to give some background about the subject.
73
wd4dda
What suprizes me is how Many of the Hater,s don't want to know what the Video is about but are so Clever they still haven't worked out how to fast forward past the explanation part...
Seems common sense to me and the vast majority of the viewer's that we need an explanation 1st so we know what we are learning.
Hi Kevin, thanks for doing your great videos. In order to get optimal NVIS propagation, you must be operating below the F0Fc frequency. This freq changes quite a bit during a 24 hour period. Best NVIS comms are a little below FoFc, 5 to 10%. Real time F0Fc can be found here: www.sws.bom.gov.au/HF_Systems/6/5
Keep up the great videos.
73
Ken WB9QDL
Colorado
Vietnamese
@08:50 Yes, seems to me also that... Đó là tiếng Việt.
Thanks! Now I know what it sounds like.
Good call, I thought it might be Thai.
That language you were wondering about is Vietnamese.
1200 could be Koren callrnia pomona might bee kg6mn
KEVIN since i dont have a ham radio call sign i can get ur email to send you the schematic for my cw code practice oslater what you want me to do
Loughkb at yahoo dot com
You’re close to David Cassler. Ke0og, maybe you could do a video together with him.
530 miles. Not that close!
Kevin Loughin close enough for a radio contact with nvis. 😉
Hello, what program are you using to map your WSPR contacts?
I did a video on that.
ua-cam.com/video/kZNkdsjeP94/v-deo.html
Try explaining radio waves to flat earthers that they prove the earth is a globe
One question, when both stations have NVIS, how much of a difference is there. Also, when only one has it, how do the numbers show signal levels. Your wsper maps were most likely shwoing stations which did not have NVIS. Here, at night, 80 meters is "going long" and making local nets very tough copy. One set of stations is about 60 miles, the other is 120 miles I'm estimating. In the AM propagation is great on 80, at night terrible. So trying NVIS hoping for some results. That language might have been Indonesian. Correct on 8mhz and lower . The only thing I'm seeing is a reflector laying on the ground is sometimes recommended, say 5% longer .. Would love to do some tests with NVIS at the other end. I believe there is a chance that was done by OH8STN here ua-cam.com/video/F0TkJJIsY3o/v-deo.html
For two way comms to work best, both stations should use nvis antennas. But there is a distinct advantage when only one is.
@@loughkb The heighth I've used is too high. Need to come down from 10/12 to 6. And try the reflector on the ground. 80 at night is terrible, we have a net at 6:30
1120 isn't Korean, I am fluent. The audio is low on the video but maybe Thai? Definitely not Japanese, and probably not Chinese.
9:04 I’m not making any jokes … the Chinese sounding station could be California? 😂 I mean, that could be Taiwanese, for example. It’s *probably* an American signal.
Vietnamese.
For someone who calls themselves "the old tech guy"... you sure have few wrinkles
Have teaching methods changed? Show me first then explain?
Yes, don't change for the minority. Explain first then show.