Very good description of ionospheric propagation. An antenna with the current node placed higher up and the voltage node at the bottom will provide a lower take off angle. Examples include Half Square and Bruce Array antennas that will do this from relatively low heights.
Is it possible to adjust the take off angle of a vertical antenna to make contacts in your skip zone? A form of NVIS? My target range is 300-600 miles on 20 meters.
Short answer yes. The answer is in the name. "Near-vertical incidence." I. My limited experience, the lower you make your antenna, the sharper upwards your takeoff angle is, and therefore you get more NVIS. I disagree with him in the video that when you get too vertical that the HF penetrates. That isn't always the case and is highly dependent on the wavelength and how iononized the atmosphere is. If the "gap" between the ions is small enough, even a directly vertical beam would not penetrate as long as the wavelength is wider than the gaps between all the ions. I get really good NVIS rain down effect (think of it like a fountain that shoots up and rains down) that can cover 300 miles or so, even covering deadspace behind mountains and whatnot. Hope that helps.
You start the beam at the bottom of the vertical line. Does the vertical line represent the entire length of the antenna, and the beam only is “measured” or represented from the feed point of the vertical ,or does the antenna truly beam / radiate most of the energy from the bottom? If I have a 20’ vertical ground plane, at 25 feet to the feed point, would the whole antenna not radiate? Or do we imagine that your vertical line only represents where the antenna is, and the pattern emanates from the entire antenna proper? Thanks in advance! KF8CYZ/AG
I thought og stood for "original gangster" for the amateur radio world, didn't think it was supposed to be the name of a pastry, but umm....thanks for the explanation!!
Good day fellow hams! I have a question regarding HF propagation may be a range of 7 MHz to 21 MHz, is there any advantage on transmit or receive by placing the dipole antenna and transceiver at the higher ground? Please comment on some advice, it is an important factor for me to go up on the higher ground versus the populated-dense city of mine. Thanks!
Yes. Higher is better. Double the height above terrain gives you four times the signal, & even better if you are on the top of a hill and the terrain around you slopes down.
Just curious, if somehow the antenna is made higher, be it on an edge of a high rise, a tower, or just a pole with a good ground plane or radial system. Will the angle be lower or just shoot out at the same angle just higher?
I've taken the scenic route to the OCF dipole. It'll be my next one. As for the low takeoff angle, what if you live in a hole and have hills or mountains all around you. I've been listening to the web SDRs to test my propagation. depending on direction, 40m gives 300-600 miles and 20m is 1000+.
The biggest issue for DX is power. Signal level decreases by a factor of four each time the distance is doubled all other factors being the same. Yes, the band sometimes do wonderful things! Most antenna improvements require more height and elements than most of us can put up. Still putting up whatever dipoles and at whatever height fits in your yard is often worth the try.
"Blobs" of positively charged ionospheric energy, non-geometrically shaped, similar to the white puffy (nimbus) clouds that you see against what appears to be a blue-sky background! Honestly, working DX, Skip, is essentially a crap shoot. I don't care what you're running for a transceiver/station/antenna and particularly the *amplifier* that I like to mock operators and call it an *ample-fire*! My most favorite thing I hear, (particularly on the 11-meter band), is "Puttin' the *mull* down*!", implying some sort of an imagined umbrella of a dominating signal thinking they're satisfying their 4th Grade ego. KD8EFQ/73, SUBSCRIBED!
Thanks for explaining this concept! I was trying to figure out why so many antennas have such low angles. It doesn't make sense until you figure in the curvature of the earth.
Hi, I certainly have not invested the time and effort to draw any detailed conclusions myself, however I did use a 40m horizontal dipole at 10m with reflectors to optimise the NVIS performance. It was fantastic up to about 500 miles radius but did not work much DX which suited me very well at the time. Times change and I think that I will temporarily at least go back to a vertical... thank you for the cloud analogy of the ionosphere, I always pictured it as a progressive fog of ionisation but your model is probably much more accurate!
I decided I wanted to have a regional station because I did not have the resources to create a great DX station. I think this aspect is overlooked in the hobby, even though it describes the 100 Watt and a Wire base to a T. Skip is strange, but I can not tell how much is skips vagerities and what is my antenna's quirks. Nice discussion yet again Dave.
Numerically, it would be modelled by ray tracing, because the wavelength (160m) is much shorter than the wave guide (the space between the Earth to ionosphere~100,000m) dimension, or the distance travelled, this is the 'optical limit' in propagation or scattering (light/RF and acoustics), but you're right about that it's virtually an infinite number of these beams all bundled together incoherently in a finite width beam, and I agree with everything you say. Great vids, David.
Callum, M0MCX KNOWS WHAT HE TALKS ABOUT AND OFTEN ILLUSTRATE IT WITH SOFTARE AND ELECTRONICALLY. BUT THAT AREN'T ALWAYS NEEDED! 5° TAKEOFFANGLE OR BELOW IS QUITE SUFFICIENT! 73s de Gus
Just for fun ... May Dad acquired a nickname "Cranky Cross" when he was younger. In my teens I started teasing him that it needed updating to "Old Grouch" which devolved to "OG." He used that in written communications with me the rest of his life.
Great topic Dave. This is the first time I heard about the -3 db points and beam width. I enjoy when you go a little further into the engineering side of radio and always learn something even if it’s just a better definition behind a term. I know you can lower the take off angle of a dipole by raising it (to a point) but what can one do to lower the take off angle of a vertical antenna. That may be a good subject for another video. Cheers from Moose Jaw. Tim VE5THF
From all that I have studied about antennas, I would say coherent waves since it is polarized. I would also cringe about any radio wave bouncing off the ground and not interfering with a stronger signal. I would go with multiple layers of air in the atmosphere bending the radio wave like a lens back to the earth, curving it plus the bounce off the ionosphere and possibly also bouncing back up from a flattish body of water. And what ever you do, don't put a repeater in the dead zone :) That is my WAG. (Wild Ass Guess).
Dave you are great. Every time you post a video I pick something new. Ham radio and fine baked goods. YES ...now about those pastries?? We'll need some coffee here... :D
Oggy (and the Oggies, fans of him) was a cartoon from a 70/80/90's UK motorbike magazine, possibly Performance Bikes, though a quick Google search for Oggy motorbike cartoon will throw you up some examples. Actually kinda cool 😎
So the Ionosphere is like Dr Who's description of time. " People assume that time is a strict progression of cause to effect, but *actually* from a non-linear, non-subjective viewpoint - it's more like a big ball of wibbly wobbly... time-y wimey... stuff."
Hello Dave and collegues! I think the cheapest antenna, valid on 80-6M, would be a loopantenna. For all these bands: Feet = 1005 /f i MHz or Metric = 306,7 /f MHz The lowest frequency 3.69MHz (QRP QRG) this would be 272,3577 Feet [83,02m]. Use 450Ohm black bandcable and feed it to balun input on transmatch! MARK: MIDPOINT DC EARTH! ELSE YOU'LL GET NASTY STATIC WHICH WILL ULTIMATELY DESTROY YOUR RXTX! IF YOU HAVE NO MIDPOINT EARTH MAKE A DISCHARGE AGAINST EARTH *B E F O R E* *CONNECTING IT TO ANY OF YOUR RXTX!* THERE MAY BE HUGHE STATIC ELEKTRICITY! *BEAWARE!* Loopantenna is a "quiet one" If midpoint DC Earth! What about loopantenna and there *takeoffangle* If mount *10-20feet of ground?NVIS?* *73s de Gunnar sm6oer >>\
Dave, I can't believe that's where OG came from! All this time, I believed you were using the common slang which is very popular and a good description of your channel: OG = original gangster It is a common slang term that is very similar to saying: old school. This is not a negative connotation, original gangster simply denotes, the original real deal. All this time I had assumed you were using OG as a fact that you are an old school ham who has been doing this for a long time! In other words, an Elmer. I am of course subscribed to your channel with notifications turned on and thumbs up! 73 W3GUY
40m band i Have a 40m delta 40 feet high, 1/4 wave vertical 16 raised verticals 2:1 fed, 22m high dipole and a 2 element 40m dipole array all spaced out. i Test daily when i can long path...with N7EKD and WA7WNH N7RY from ZS2 land , the differences is all note'able. but by far the dipole at 22m high and the 2 element (wirebeam) at 45 feet high get the job done, the Delta (quad) vertical fed is always weaker and the vertical as well, now we might think it's just conditions, i have been working N7ekd and Eric wa7lnh since 2006 on and off... when conditions allow it. My qth is near a saltwater marsh. lessons learned? Hmm... don't lend your ear to your buddy down the road giving 59 reports when you can hear only 57 or 55, your turn will come around as the grey line moves to darkness or light. with quick qsb fading days, the vertical are way better.... in static and rain, none of them beat the (short beverage)65 feet wire close to the ground 6ft up, terminated at far end 450 ohm resistor and 9:1 balun at feed on Receive.... it just cuts the static to S 2 and there the boys are. In my notes i do recall on several writing (vertical is crap) just to find 2 pages on vertical wins! It's a fur-ball really. So the end result is put up what you c an as best you can. so.............................. "Put The Fire In The Wire, Or Get The Wire Up Higher" zs2cx
You sir are a great Elmer, thank you!
LOL!!!!! This IS the best description of the ionosphere I've ever heard!!!! Great presentation Dave!!!! Love it!!!!!!
Very good description of ionospheric propagation. An antenna with the current node placed higher up and the voltage node at the bottom will provide a lower take off angle. Examples include Half Square and Bruce Array antennas that will do this from relatively low heights.
Is it possible to adjust the take off angle of a vertical antenna to make contacts in your skip zone? A form of NVIS? My target range is 300-600 miles on 20 meters.
Short answer yes. The answer is in the name. "Near-vertical incidence." I. My limited experience, the lower you make your antenna, the sharper upwards your takeoff angle is, and therefore you get more NVIS. I disagree with him in the video that when you get too vertical that the HF penetrates. That isn't always the case and is highly dependent on the wavelength and how iononized the atmosphere is. If the "gap" between the ions is small enough, even a directly vertical beam would not penetrate as long as the wavelength is wider than the gaps between all the ions. I get really good NVIS rain down effect (think of it like a fountain that shoots up and rains down) that can cover 300 miles or so, even covering deadspace behind mountains and whatnot. Hope that helps.
thanks for all that you do Dave!
Thanks!
Thank you for your financial support of this channel! It is greatly appreciated! 73, Dave, KE0OG
You start the beam at the bottom of the vertical line. Does the vertical line represent the entire length of the antenna, and the beam only is “measured” or represented from the feed point of the vertical ,or does the antenna truly beam / radiate most of the energy from the bottom? If I have a 20’ vertical ground plane, at 25 feet to the feed point, would the whole antenna not radiate? Or do we imagine that your vertical line only represents where the antenna is, and the pattern emanates from the entire antenna proper?
Thanks in advance!
KF8CYZ/AG
What microphones do you use for radio?
I thought og stood for "original gangster" for the amateur radio world, didn't think it was supposed to be the name of a pastry, but umm....thanks for the explanation!!
Dave is an original EE/ham gangster ;)
Old gangster OG
Good day fellow hams! I have a question regarding HF propagation may be a range of 7 MHz to 21 MHz, is there any advantage on transmit or receive by placing the dipole antenna and transceiver at the higher ground? Please comment on some advice, it is an important factor for me to go up on the higher ground versus the populated-dense city of mine. Thanks!
Yes. Higher is better. Double the height above terrain gives you four times the signal, & even better if you are on the top of a hill and the terrain around you slopes down.
Your first propagation explanation seems to deny the existence of near vertical incidence skywave (NVIS) radiation. Should you correct this?
my thought too
What would a vertical 5/8ths HF antenna if it was horizontal (non-radial) ? Would it radiate like a horizontal center fed dipole ? -KF8CYZ
Thanks for all ur hard work mr Dave
Dave, your description of the ionosphere sounds like my favourite dessert pudding! Very good as always...
Just curious, if somehow the antenna is made higher, be it on an edge of a high rise, a tower, or just a pole with a good ground plane or radial system. Will the angle be lower or just shoot out at the same angle just higher?
Same angle just higher.
But if its over water it might reflect off like mirror.
I've taken the scenic route to the OCF dipole. It'll be my next one. As for the low takeoff angle, what if you live in a hole and have hills or mountains all around you. I've been listening to the web SDRs to test my propagation. depending on direction, 40m gives 300-600 miles and 20m is 1000+.
The biggest issue for DX is power. Signal level decreases by a factor of four each time the distance is doubled all other factors being the same. Yes, the band sometimes do wonderful things! Most antenna improvements require more height and elements than most of us can put up. Still putting up whatever dipoles and at whatever height fits in your yard is often worth the try.
"Blobs" of positively charged ionospheric energy, non-geometrically shaped, similar to the white puffy (nimbus) clouds that you see against what appears to be a blue-sky background! Honestly, working DX, Skip, is essentially a crap shoot. I don't care what you're running for a transceiver/station/antenna and particularly the *amplifier* that I like to mock operators and call it an *ample-fire*! My most favorite thing I hear, (particularly on the 11-meter band), is "Puttin' the *mull* down*!", implying some sort of an imagined umbrella of a dominating signal thinking they're satisfying their 4th Grade ego.
KD8EFQ/73, SUBSCRIBED!
Thanks for explaining this concept! I was trying to figure out why so many antennas have such low angles. It doesn't make sense until you figure in the curvature of the earth.
Hi, I certainly have not invested the time and effort to draw any detailed conclusions myself, however I did use a 40m horizontal dipole at 10m with reflectors to optimise the NVIS performance. It was fantastic up to about 500 miles radius but did not work much DX which suited me very well at the time. Times change and I think that I will temporarily at least go back to a vertical... thank you for the cloud analogy of the ionosphere, I always pictured it as a progressive fog of ionisation but your model is probably much more accurate!
I decided I wanted to have a regional station because I did not have the resources to create a great DX station. I think this aspect is overlooked in the hobby, even though it describes the 100 Watt and a Wire base to a T. Skip is strange, but I can not tell how much is skips vagerities and what is my antenna's quirks. Nice discussion yet again Dave.
Does this work with giant stadium spotlights too or just radio antenna thingies?
Numerically, it would be modelled by ray tracing, because the wavelength (160m) is much shorter than the wave guide (the space between the Earth to ionosphere~100,000m) dimension, or the distance travelled, this is the 'optical limit' in propagation or scattering (light/RF and acoustics), but you're right about that it's virtually an infinite number of these beams all bundled together incoherently in a finite width beam, and I agree with everything you say. Great vids, David.
Even higher 300-400 km above
Earth! [abt 400.000 m]! *It gets ionized by the Sun in summer!*
Also see DC Commander videos where he model verticals with software and analyze the angle
Callum, M0MCX KNOWS WHAT HE TALKS ABOUT AND OFTEN ILLUSTRATE IT WITH SOFTARE AND ELECTRONICALLY.
BUT THAT AREN'T ALWAYS NEEDED! 5° TAKEOFFANGLE OR BELOW IS QUITE SUFFICIENT! 73s de Gus
---> DX Commander.
Just for fun ... May Dad acquired a nickname "Cranky Cross" when he was younger. In my teens I started teasing him that it needed updating to "Old Grouch" which devolved to "OG." He used that in written communications with me the rest of his life.
Great topic Dave. This is the first time I heard about the -3 db points and beam width. I enjoy when you go a little further into the engineering side of radio and always learn something even if it’s just a better definition behind a term. I know you can lower the take off angle of a dipole by raising it (to a point) but what can one do to lower the take off angle of a vertical antenna. That may be a good subject for another video. Cheers from Moose Jaw.
Tim VE5THF
Will a 40 M dipole 6 feet off the ground have the same takeoff angle as a 20 M dipole that is also 6 feet off the ground?
no but at that height it will be very close to straight up for both.
From all that I have studied about antennas, I would say coherent waves since it is polarized. I would also cringe about any radio wave bouncing off the ground and not interfering with a stronger signal. I would go with multiple layers of air in the atmosphere bending the radio wave like a lens back to the earth, curving it plus the bounce off the ionosphere and possibly also bouncing back up from a flattish body of water. And what ever you do, don't put a repeater in the dead zone :) That is my WAG. (Wild Ass Guess).
Very interesting, thanks Dave.
Dave, you are a brilliant Elmer!
Dave you are great. Every time you post a video I pick something new.
Ham radio and fine baked goods. YES
...now about those pastries?? We'll need some coffee here... :D
Thank you Dave- always great! And congrats on your new QST section! de WI2C John
That was great. Thank you.
Great Great video Dave
Our exotic dx palace consists of many monoband yagis. Not one vertical. Except when the exotic dancers come in.
Oggy (and the Oggies, fans of him) was a cartoon from a 70/80/90's UK motorbike magazine, possibly Performance Bikes, though a quick Google search for Oggy motorbike cartoon will throw you up some examples. Actually kinda cool 😎
Much better picture now, thank you Dave..this means I need a field array to cover all angles! Hihi
73,
Gary KB8QLZ
Thanks Dave! Great video, I learned a lot. 73, Casey KE8PFA
Dave, I thought the Earth was flat?!! Is you on Mars by mistake?
So the Ionosphere is like Dr Who's description of time. " People assume that time is a strict progression of cause to effect, but *actually* from a non-linear, non-subjective viewpoint - it's more like a big ball of wibbly wobbly... time-y wimey... stuff."
Thank you, Dave.
That was a very good explanation.
My Welsh ancestors and kin probably appreciate he pastry comments. N0QFT
Hello Dave and collegues!
I think the cheapest antenna, valid on 80-6M, would be a loopantenna. For all these bands:
Feet = 1005 /f i MHz or
Metric = 306,7 /f MHz
The lowest frequency 3.69MHz
(QRP QRG) this would be 272,3577 Feet [83,02m].
Use 450Ohm black bandcable and feed it to balun input on
transmatch! MARK: MIDPOINT
DC EARTH! ELSE YOU'LL GET NASTY STATIC WHICH WILL ULTIMATELY DESTROY YOUR
RXTX!
IF YOU HAVE NO MIDPOINT EARTH MAKE A DISCHARGE AGAINST EARTH *B E F O R E* *CONNECTING IT TO ANY OF YOUR RXTX!* THERE MAY BE HUGHE STATIC ELEKTRICITY!
*BEAWARE!*
Loopantenna is a "quiet one"
If midpoint DC Earth!
What about loopantenna and there *takeoffangle* If mount
*10-20feet of ground?NVIS?*
*73s de Gunnar sm6oer >>\
“Oggi” stands for “today” in Italian.
Dave, I can't believe that's where OG came from!
All this time, I believed you were using the common slang which is very popular and a good description of your channel:
OG = original gangster
It is a common slang term that is very similar to saying: old school.
This is not a negative connotation, original gangster simply denotes, the original real deal.
All this time I had assumed you were using OG as a fact that you are an old school ham who has been doing this for a long time! In other words, an Elmer.
I am of course subscribed to your channel with notifications turned on and thumbs up!
73 W3GUY
I thought that OG = "Old Guy" (as well as OM = "Old Man").
I was thinking “Original Gangsta”!!!!
How about giving us a Welsh Ogi recipe. Part Welsh I am.
I watched this
40m band
i Have a 40m delta 40 feet high, 1/4 wave vertical 16 raised verticals 2:1 fed, 22m high dipole and a 2 element 40m dipole array all spaced out. i Test daily when i can long path...with N7EKD and WA7WNH N7RY from ZS2 land , the differences is all note'able. but by far the dipole at 22m high and the 2 element (wirebeam) at 45 feet high get the job done, the Delta (quad) vertical fed is always weaker and the vertical as well, now we might think it's just conditions, i have been working N7ekd and Eric wa7lnh since 2006 on and off... when conditions allow it. My qth is near a saltwater marsh.
lessons learned? Hmm... don't lend your ear to your buddy down the road giving 59 reports when you can hear only 57 or 55, your turn will come around as the grey line moves to darkness or light.
with quick qsb fading days, the vertical are way better.... in static and rain, none of them beat the (short beverage)65 feet wire close to the ground 6ft up, terminated at far end 450 ohm resistor and 9:1 balun at feed on Receive.... it just cuts the static to S 2 and there the boys are.
In my notes i do recall on several writing (vertical is crap) just to find 2 pages on vertical wins! It's a fur-ball really.
So the end result is put up what you c an as best you can.
so..............................
"Put The Fire In The Wire, Or Get The Wire Up Higher"
zs2cx
Firestick made one !
But, but, I thought the earth is FLAT! Oh well.....
Oggy is indeed Cornish. It's a very popular food here in Cornwall called a pasty. The Cornish often refer to the pasty as an oggy.
De G0SDT