Hi Tim, I've a mosly 5 band yagi, with one element on 17M, little or no gain..It's 10M above the ground and I've worked JA a few times on 17M with 100w. 17M is an underrated band, great for exotic stations...
Thank you, Tim. I think this is valuable content for ham radio beginners like me. 🙂 With my current level of understanding, it seems to me that for the higher HF bands like 15 m it makes sense to stay with a vertical as for these wavelengths it is relatively easy to mount something like an EFHW monoband vertically, whereas for the lower bands this is getting more difficult and it makes more sense to consider the flat-tops or the inverted V setup. So, thanks again for demonstrating the differences between these 2 latter antenna shapes. 73 de DO1HNR (German class E, so no need for 20m and 40 for the time being, but hopefully that'll change soon 😉)
Sounds like the Inverted V is ideal for NVIS. Not too much of a hustle to set up for 40m, since all you need is a tree and a couple of guy rods. Thank you for the detailed explanation!
In photography, we call a certain group of people "pixel peepers". This group of people look for pixels or specific details no one else "in the main" would ever see in a photograph. Well, I've noticed in ham radio, we also have a group of folks called "radiation pattern peepers". This group of people look for different radiation patterns, like between the inverted V and Flat top. Bottom line is, no one would be able to tell on the receiving end what antenna being used between the 2 antenna's. However, having said that, I feel this information is very useful from an academic perspective in learning how different things change as changes are made to the antenna. So, really good information. However, I can't stress enough the diagrams/FF plots etc. look larger than they actually are. Meaning many of these changes in signal strength are minor, but the graph makes it look like a huge change. Hope that is constructive in my best opinion :) Best Regards and 73
Some of your viewers might not know that antenna gain is the product of antenna efficiency and directivity. It’s helpful to consider those two contributors separately when comparing the two configurations. If we ignore the presence of the ground, both the straight dipole and inverted V will have very similar broadside directivity. But the bend should broaden the elevation pattern, reducing the directivity straight up and spreading that power over a wider angle. Their radiation efficiency should be identical. Now consider the ground. Assuming both antennas have the same maximum height, the inverted V will obviously have a lower average height. Near broadside we have horizontal polarization and the ground reflection pushes the peak of the lobe to a higher elevation angles. The lower the antenna the more that lobe moves. That can be an advantage or disadvantage, depending on the distance you are trying to reach. Up to here I’m ignoring ground losses. They will have an effect on radiation efficiency as the antenna height decreases, but at typical heights I suspect that’s a relatively small contributor to gain compared to the effect on directivity. You mentioned that the inverted V provides a closer match to a 50 ohm feed. That’s true, but I don’t think a mismatch to a 70 ohm feed of a high dipole is much of a hit to radiation efficiency or SWR loss in a typical feedline, so it’s not a deciding factor. The above observations are based on general knowledge not calculations, so if someone finds a misstatement feel free to point it out.
(copying to a main comment from my reply) One of the huge benefits of an inverted-V, or in my case a double inverted-V (in our club we call is a cross-V) is that it can be self supporting with a single mast. I setup mine for about 120 deg included angle with legs for 20 and 40 meters and can easily work 15 on the 40m legs since it's the 3rd harmonic. More bands "work" with most radio's built in 3:1 tuner. Perfect for EMCOMM where most of your work would be
Good analysis Tim 😀 I think in practice it would be hard to notice the sometimes subtle differences between the two 🤔 However, having two options gives you variations to get as much wire into the garden as possible and as high as you can , as these two factors will probably be more influential? I think the different mounting options of flat versus V is also a positive when it comes to what’s possible in the given space 👍🏻 Thanks 😀
I remember being a kid with not much money and having to make an inverted V and taped it to my bedroom wall lol. It was a bit directional but it worked.
Thank you so much for your explanation about these kind of antenna. 😊 but some reason i still choosing inverted vee antenna:🙏🏻👍🏻 in the Bonsai type model😁
These models are great, and show, I think, that they are basically equivalent because the point to point path and signal reliability will depend much more on conditions, which change unpredictably in both time and space, than the differences in these two configurations. That is, 1-2dB here or there, or a few percent here or there, on the antenna, is
As an Antenna can't have a power gain it's all swings and roundabouts. Affective gain just means that the power you have is being funnelled in a particular direction. So if it's omnidirectional then the gain will be zero or less due to losses. hence to get high affective power gain you need to be able to rotate the antenna as the beam width will be reduced to a narrow angle. My G5RV with the centre at about 12m is great to some places and C**P to others. I've gained on the swings but lost on the roundabout. Just waiting for the 17m 4ele at 20m to fit within the bank balance. ;-)
If the radiation pattern of a center-fed dipole is circular around its axis, can't it be turned to the vertical orientation to be an omnidirectional antenna? If so, how high off the ground would it need to be mounted? 1/2-wave (so the "top" would be 3/2-waves of the ground) or is it more important to have the upper element 1/2 wave off the ground( which would essentially have the "ground" side near the ground). In my case for a CB (11M) antenna. Another question about the "Inverted V" dipole: when the "V" is 90 degrees, doesn't that tend to make it an inverted ground plane antenna?
For the vertical Halfwave dipole as with the horizontal version, the max current is in the centre part of the antenna so enabling this to be as high as possible is good. However, you do have an omni directional pattern and the key is to try and get the lower leg as far above ground as you can (and away from the reach of people as voltages will be high at the ends).
Comparing inverted-V (downward pointing) with a flat dipole made me want to see what would happen if the angle continued upward into an upward-pointing V. I don't expect that it would make an effective antenna since I've never seen anyone use such a thing, but I would love to know what happens to the feedpoint impedance and radiation pattern.
@@alzeNL Exactly. One of the huge benefits of an inverted-V, or in my case a double inverted-V (in our club we call is a cross-V) is that it can be self supporting with a single mast. I setup mine for about 120 deg included angle with legs for 20 and 40 meters and can easily work 15 on the 40m legs since it's the 3rd harmonic. More bands "work" with most radio's built in 3:1 tuner. Perfect for EMCOMM where most of your work would be
Like going back to school. Except you learn something here!👍☘️
Hi Tim, I've a mosly 5 band yagi, with one element on 17M, little or no gain..It's 10M above the ground and I've worked JA a few times on 17M with 100w.
17M is an underrated band, great for exotic stations...
Thank you, Tim. I think this is valuable content for ham radio beginners like me. 🙂
With my current level of understanding, it seems to me that for the higher HF bands like 15 m it makes sense to stay with a vertical as for these wavelengths it is relatively easy to mount something like an EFHW monoband vertically, whereas for the lower bands this is getting more difficult and it makes more sense to consider the flat-tops or the inverted V setup. So, thanks again for demonstrating the differences between these 2 latter antenna shapes.
73 de DO1HNR (German class E, so no need for 20m and 40 for the time being, but hopefully that'll change soon 😉)
Welcome to the hobby and thank you!
Sounds like the Inverted V is ideal for NVIS. Not too much of a hustle to set up for 40m, since all you need is a tree and a couple of guy rods. Thank you for the detailed explanation!
Totally agree and you are welcome!
Tim, Very good video...Thanks I use a 10 Meter Dipole Sloped and get very good performance Thank You
Thank you!
Great explanation re angle of the inverted V, I am hooking 2 metres extra tie off strings to my SOTA dipole ends and checking it this afternoon.
Enjoy!
In photography, we call a certain group of people "pixel peepers". This group of people look for pixels or specific details no one else "in the main" would ever see in a photograph. Well, I've noticed in ham radio, we also have a group of folks called "radiation pattern peepers". This group of people look for different radiation patterns, like between the inverted V and Flat top. Bottom line is, no one would be able to tell on the receiving end what antenna being used between the 2 antenna's. However, having said that, I feel this information is very useful from an academic perspective in learning how different things change as changes are made to the antenna. So, really good information. However, I can't stress enough the diagrams/FF plots etc. look larger than they actually are. Meaning many of these changes in signal strength are minor, but the graph makes it look like a huge change. Hope that is constructive in my best opinion :) Best Regards and 73
Oh I’m a peeper!
Some of your viewers might not know that antenna gain is the product of antenna efficiency and directivity. It’s helpful to consider those two contributors separately when comparing the two configurations.
If we ignore the presence of the ground, both the straight dipole and inverted V will have very similar broadside directivity. But the bend should broaden the elevation pattern, reducing the directivity straight up and spreading that power over a wider angle. Their radiation efficiency should be identical.
Now consider the ground. Assuming both antennas have the same maximum height, the inverted V will obviously have a lower average height. Near broadside we have horizontal polarization and the ground reflection pushes the peak of the lobe to a higher elevation angles. The lower the antenna the more that lobe moves. That can be an advantage or disadvantage, depending on the distance you are trying to reach.
Up to here I’m ignoring ground losses. They will have an effect on radiation efficiency as the antenna height decreases, but at typical heights I suspect that’s a relatively small contributor to gain compared to the effect on directivity.
You mentioned that the inverted V provides a closer match to a 50 ohm feed. That’s true, but I don’t think a mismatch to a 70 ohm feed of a high dipole is much of a hit to radiation efficiency or SWR loss in a typical feedline, so it’s not a deciding factor.
The above observations are based on general knowledge not calculations, so if someone finds a misstatement feel free to point it out.
Very intresting and really well explained. Can certiainly tell your an educational professional.
Hi Mike,
Very good analysis of the dipole and inverted V. MMANA sure makes modeling the antenna easy. You and the family stay safe. 73 WJ3U
You too Don 73
(copying to a main comment from my reply)
One of the huge benefits of an inverted-V, or in my case a double inverted-V (in our club we call is a cross-V) is that it can be self supporting with a single mast. I setup mine for about 120 deg included angle with legs for 20 and 40 meters and can easily work 15 on the 40m legs since it's the 3rd harmonic. More bands "work" with most radio's built in 3:1 tuner. Perfect for EMCOMM where most of your work would be
Good analysis Tim 😀 I think in practice it would be hard to notice the sometimes subtle differences between the two 🤔 However, having two options gives you variations to get as much wire into the garden as possible and as high as you can , as these two factors will probably be more influential? I think the different mounting options of flat versus V is also a positive when it comes to what’s possible in the given space 👍🏻 Thanks 😀
Agree 100%
I remember being a kid with not much money and having to make an inverted V and taped it to my bedroom wall lol. It was a bit directional but it worked.
Got you on the air 👍👍
Thank you so much for your explanation about these kind of antenna. 😊 but some reason i still choosing inverted vee antenna:🙏🏻👍🏻 in the Bonsai type model😁
You’re welcome
Thank U very much for this very interesting video!
My pleasure!
These models are great, and show, I think, that they are basically equivalent because the point to point path and signal reliability will depend much more on conditions, which change unpredictably in both time and space, than the differences in these two configurations. That is, 1-2dB here or there, or a few percent here or there, on the antenna, is
Yep inverted v work fine
Enjoyed our short QSO today. Hope the chores went well! 2M0TFP.
Hi Tony. A pleasure to work you .. yes all good! Sunburnt though lol 73
As an Antenna can't have a power gain it's all swings and roundabouts. Affective gain just means that the power you have is being funnelled in a particular direction. So if it's omnidirectional then the gain will be zero or less due to losses. hence to get high affective power gain you need to be able to rotate the antenna as the beam width will be reduced to a narrow angle.
My G5RV with the centre at about 12m is great to some places and C**P to others. I've gained on the swings but lost on the roundabout.
Just waiting for the 17m 4ele at 20m to fit within the bank balance. ;-)
Very true. I’d love to rotate my Hf antenna but no room sadly
If the radiation pattern of a center-fed dipole is circular around its axis, can't it be turned to the vertical orientation to be an omnidirectional antenna? If so, how high off the ground would it need to be mounted? 1/2-wave (so the "top" would be 3/2-waves of the ground) or is it more important to have the upper element 1/2 wave off the ground( which would essentially have the "ground" side near the ground). In my case for a CB (11M) antenna.
Another question about the "Inverted V" dipole: when the "V" is 90 degrees, doesn't that tend to make it an inverted ground plane antenna?
For the vertical Halfwave dipole as with the horizontal version, the max current is in the centre part of the antenna so enabling this to be as high as possible is good. However, you do have an omni directional pattern and the key is to try and get the lower leg as far above ground as you can (and away from the reach of people as voltages will be high at the ends).
nice video om!!!
Thank you! 73
Have manual for AMNNA would like like to use it. Have a 5 band 2 element at 35 ft. Mosley - 33 - M- WARC at 60 ft.
Good explanation Tim 👍👏👏
Thanks!
Very helpful thanks
Thanks!
Comparing inverted-V (downward pointing) with a flat dipole made me want to see what would happen if the angle continued upward into an upward-pointing V. I don't expect that it would make an effective antenna since I've never seen anyone use such a thing, but I would love to know what happens to the feedpoint impedance and radiation pattern.
NVIS maybe ? intresting to try out, esp on 10m!
@@alzeNL Exactly. One of the huge benefits of an inverted-V, or in my case a double inverted-V (in our club we call is a cross-V) is that it can be self supporting with a single mast. I setup mine for about 120 deg included angle with legs for 20 and 40 meters and can easily work 15 on the 40m legs since it's the 3rd harmonic. More bands "work" with most radio's built in 3:1 tuner. Perfect for EMCOMM where most of your work would be
Ey up Tim. Good job.
Nick M1DDD
You tell me 😂😂😂😂
Excuse me, do you have an email address?
Via my QRZ.com profile
You need to haircut 😢😢😢😢😢😢😂😂😂
Noted x
👍 de ei8eub
Thanks 👍