Wow.. This is interesting.. Tilted Ground - or Tilted Antenna. Fascinating experiment! Callum. • The Truth About Optimi... - the video about the 5 degrees
On Wolf Mountain in northern California, I did phase two twenty meter yagis that were side by side at 65 feet apart using a homebrew phasing box that had 5 positions and extensive impedance matching. The slope towards EU was about 10% downhill. I can tell you that over 20 years of experience the system worked great. I estimated the additional gain at a couple of dB. My 2 cents or maybe my 2dB. 73, Jim W6LG now at about sea level
All of our mountain top repeater colinear antennas have 5 degree downtilt. We had the wrong antenna sent to us by the manufacturer a few years ago and noticed it's performance, well, it sucked. After several back and forth phone calls they realized they had sent us the wrong antenna. It had 0 degrees of downtilt when we had specified 5 degrees of downtilt. On a 21 foot long antenna with a 7 degree vertical beamwidth those 5 degrees of downtilt make a HUGE difference. We lost 20 to 30 miles of range on the system with the wrong downtilt.
Mmana-Gal is a bad tool for antennas lower than 0.2 WL, for example horizontal dipoles near the ground, loops, etc. because of MiniNEC. Results are wrong and overoptimistic. Sommerfeld Norton is more accurate. NEC2 or NEC4 is the tool.
Gain figures are wrong because of ground attenuation. I have used Mmana, and still using it, but be aware of supergain superlow dipoles with fancy reflectors over the ground... Here is an example, low dipole for 40M at 2 meters off the ground. Mmana says it has 10.59 dBi... but NEC says it has 0.02 dBi. Z (Mmana = 8 ohm) Z (NEC = 52 ohm) * 7.1 ***Wires*** 1 0.0, -10.32, 0.0, 0.0, 10.32, 0.0, 8.000e-04, -1 ***Source*** 1, 0 w1c, 0.0, 10.0 ***Load*** 0, 0 ***Segmentation*** 800, 80, 2.0, 2 ***G/H/M/R/AzEl/X*** 2, 2.0, 0, 50.0, 120, 60, 0.0 ###Comment### @@DXCommanderHQ
Very interesting subject. I have a dual polarized 4 element yagi ( 4 vert/ 4 horz) and tilted it about 5 degrees. The main reason i did this was to take my aluminum mast pole out of line with the vertical elements. However, i can tell you it made an amazing difference for weak stations on DX as conditions fade. . Don't notice it so much when the band is wide open, but when the signals get weak i can work them way easier than ever before. And my noise floor is nothing. On the other side of that, my vertical works equally as impressive with local communications. It turned out to be a happy accident.
It's also what happens with an open vee, which when you think about it, is just two slopers 45 degrees out from each other. But goof with a vertical, and you've just done what the military does with their sloped over mobiles, you've gone Skywave. All the Best! 73 DE W8LV BILL
It was a really good question and answer. I finally know how an antenna behaves in an environment so that I can evaluate the environment and its influence. Until today I thought that the power comes from the smaller angle. Now I know that I was wrong with my assumption. That was the last puzzle I didn't understand to build my own good antenna. Thank you very much Cal. 73. P.s. that is also the reason why you get a better signal on a mountain. It's the angle to the ground. @@DXCommanderHQ
Ant experimenting is great, but as i just found after spending 2 months getting my 20m 3 ele parisitic working great, propagation went and i was left with a empty log but still a bowl of nanas, i love banana hi.
At HF frequencies, I’m wondering if; for an antenna, the earth is a ‘micro earth’ or an ‘infinite earth’, because if when conceptually zoomed out a number of wavelengths/miles, the local terrain where the antenna is located becomes irrelevant to antenna performance… At VHF frequencies, which tend to optical line-of-sight propagation properties, then the example becomes different and probably needs to be qualified in an example.
@@DXCommanderHQ exactly, when multiple wavelengths away from the antenna, its orientation relative to the Earth becomes largely insignificant. It’s always useful in science to explore the limits to get a good understanding of the concepts, ie dry short range and extreme range.
Tilt your yagi to 15 degrees and you can work 70% of the amateur radio satellites passes, with your normal azimuth rotator, I did it for ages like that before I got the G5500 AZ/EL rotator.
Yes Robbie.. I did some modelling just the other day.. Low to the ground, my 17 element Tonna would basically give me between about 10 and 80 degrees at good gain.. Next job! (after the next job - after the next job!)
I have seen a Band 2 (Broadcast VHF radio) site where it had an omni directional down tilted pattern. 2 vertical dipoles one above the other but fed with a slight phase shift (top antenna fed a few degrees advance of the lower one). Unlike amateur radio they wanted to confine their RF to the local area, but of course the technique could be adapted...
Most cellular antennas have a physical down tilt. There can be a fixed tilt or you can install RET units - Remote Electrical Tilt, a motor where you can remotely change the amount of down tilt to "tune" the network.
Talk about turning antenna theory on its head. Fascinating idea to lean the antenna over and improve the gain in the appropriate direction. nice one Cal.
For my money, and from my experience, the hypothesis is true - very true. My DXC Classic is located about 700’ ASL on ground that slants away at about 15+ deg towards Europe/Africa (I’m East Coast US). I’m constantly getting great signal reports with only 100W. I’ve even had some stations question my truthfulness regarding my power and vertical antenna claim. On yesterday’s live stream (3/10/24) you can hear me at the 48:42 mark with 100 watts into my DXC - a bit over 3500 miles. Nothing special; a 7300 at 100W into the DXC. Needless to say, I’m happy with the performance and believe that the sloping landscape increases my low takeoff angle gain - of sorts. My WSPR plots also validate the increase in reception and signal strength in the direction of the slope.
Brilliant topic Callum and one i think is fact as my location takes full advantage of this theory. Just a shame behind me is around a 1000ft hill full of iron, although unless it’s all in my head i am almost certain it acts like a huge reflector but predominately in one direction and mainly noticeable on VHF/UHF….Please tell me i am talking out of my backside…🤓
This is actually a question on the US Amateur Extra exam. (Just passed it last month....humblebrag) Sloping ground will give a lower takeoff angle and more gain, facing downhill.
I remember back in the 1970's/80's going out in the hills and a pre-arranged sked with two stations on 70.260 MHz with my a.m. Pye Bantam with ½ Watt out with a telescopic ¼λ vertical on the Bantam. I did get a stronger signal on the hillside than at the top. The signal had dropped out by going about 6 feet on the other side but it was quite a steep drop on that side. G4GHB.
Very interesting - and helpful! I use a carbon fiber pole to hold my 1/4 wave wire verticals and I run them at about a 5-10 degree slant away from the pole to keep interactions under control. I've been slanting it toward the East. Now I'm going to have to experiment with which direction I slant it.
The Angle effect is very noticeable when mobile and driving up hill, signals are usually stronger whilst climbing than when on the top of the hill. of course the angle of antenna against the ground or the vehicle is still 90 but something improves that's for sure
Great video, very interesting and it is great to question how things work and experiment to see how you can maybe improve something. Antennas are equally fascinating as they are to your shack set up. Big thank you for the mentions, now the lighter evenings are with us i will be making more antennas and experimenting (like my actual extending ladder antenna i did for your competition). All the best, regards Steve aka Enthusiast Steve M6WVV
I had a 4Square on 20M, on Pamlico Sound, in the water and compared to a guy in CT using 4 over 4 over 4. My 4Sq was always louder, everywhere, all the time.
Callum please keep feeding chatGPT your antenna science. One day it might be able to build the most perfect antenna for every situation. 👍 Fascinating stuff, thank you ad always for your insight and videos.
Me too. Plenty of slopes around Caerphilly to experiment with. At my "home" GW QTH in the Rhondda, I'm right down the bottom of the valley, but on the western slope. My 80m DX seems to be to the USA though, strangely.
Just did this a few days ago as an experiment on a 4th storey balcony with 20degre tilt and tilted radials, folded back at 2meters and linear top loaded to 10m. 1:1.1 and great dx results. Inspired by your explanation of folding and ratios involved.
On Wolf Mountain in northern California, I did phase two twenty meter yagis that were side by side at 65 feet apart using a homebrew phasing box that had 5 positions and extensive impedance matching. The slope towards EU was about 10% downhill. I can tell you that over 20 years of experience the system worked great. I estimated the additional gain at a couple of dB. My 2 cents or maybe my 2dB. 73, Jim W6LG now at about sea level
I was just talking about this with W7sx at his remote station. He found the same results. 73 Jim
Great stuff Jim!!
Mine is tilted most of the time very windy on the east coast of the south Island lol 73 ZL4SY
Easy to do on a Signature 9 DX Commander. Just put your post in the ground tilted….ask me how I know!😂😂
HAHAHA!!!
All of our mountain top repeater colinear antennas have 5 degree downtilt. We had the wrong antenna sent to us by the manufacturer a few years ago and noticed it's performance, well, it sucked. After several back and forth phone calls they realized they had sent us the wrong antenna. It had 0 degrees of downtilt when we had specified 5 degrees of downtilt. On a 21 foot long antenna with a 7 degree vertical beamwidth those 5 degrees of downtilt make a HUGE difference. We lost 20 to 30 miles of range on the system with the wrong downtilt.
Wow.. Yes!
Mmana-Gal is a bad tool for antennas lower than 0.2 WL, for example horizontal dipoles near the ground, loops, etc. because of MiniNEC. Results are wrong and overoptimistic.
Sommerfeld Norton is more accurate. NEC2 or NEC4 is the tool.
There is a known maths issue for antennas under 1/4 wavelength for impedance. The far field plots are fine - and match to NEC2
Gain figures are wrong because of ground attenuation. I have used Mmana, and still using it, but be aware of supergain superlow dipoles with fancy reflectors over the ground...
Here is an example, low dipole for 40M at 2 meters off the ground. Mmana says it has 10.59 dBi... but NEC says it has 0.02 dBi.
Z (Mmana = 8 ohm)
Z (NEC = 52 ohm)
*
7.1
***Wires***
1
0.0, -10.32, 0.0, 0.0, 10.32, 0.0, 8.000e-04, -1
***Source***
1, 0
w1c, 0.0, 10.0
***Load***
0, 0
***Segmentation***
800, 80, 2.0, 2
***G/H/M/R/AzEl/X***
2, 2.0, 0, 50.0, 120, 60, 0.0
###Comment###
@@DXCommanderHQ
Choosing a /P location which has ground/slope gain in the right/all direction is a great bonus. Thanks Callum 👍🏻
Yes Ian..
Very interesting subject. I have a dual polarized 4 element yagi ( 4 vert/ 4 horz) and tilted it about 5 degrees. The main reason i did this was to take my aluminum mast pole out of line with the vertical elements. However, i can tell you it made an amazing difference for weak stations on DX as conditions fade. . Don't notice it so much when the band is wide open, but when the signals get weak i can work them way easier than ever before. And my noise floor is nothing. On the other side of that, my vertical works equally as impressive with local communications. It turned out to be a happy accident.
It's also what happens with an open vee, which when you think about it, is just two slopers 45 degrees out from each other. But goof with a vertical, and you've just done what the military does with their sloped over mobiles, you've gone Skywave. All the Best! 73 DE W8LV BILL
Thanks Cal. Now i understand Antennas😃😃😃 I had that Question may be 10 years in my head.
You and me both!
It was a really good question and answer. I finally know how an antenna behaves in an environment so that I can evaluate the environment and its influence. Until today I thought that the power comes from the smaller angle. Now I know that I was wrong with my assumption. That was the last puzzle I didn't understand to build my own good antenna. Thank you very much Cal. 73. P.s. that is also the reason why you get a better signal on a mountain. It's the angle to the ground.
@@DXCommanderHQ
Ant experimenting is great, but as i just found after spending 2 months getting my 20m 3 ele parisitic working great, propagation went and i was left with a empty log but still a bowl of nanas, i love banana hi.
At HF frequencies, I’m wondering if; for an antenna, the earth is a ‘micro earth’ or an ‘infinite earth’, because if when conceptually zoomed out a number of wavelengths/miles, the local terrain where the antenna is located becomes irrelevant to antenna performance…
At VHF frequencies, which tend to optical line-of-sight propagation properties, then the example becomes different and probably needs to be qualified in an example.
Paragraph 1.. You would think maybe so.. but after multiple wavelengths, you're "good to go".
@@DXCommanderHQ exactly, when multiple wavelengths away from the antenna, its orientation relative to the Earth becomes largely insignificant. It’s always useful in science to explore the limits to get a good understanding of the concepts, ie dry short range and extreme range.
My DX Commander is located on a sloping lawn. I have no choice, and I cannot really see much difference between the two directions.
Tilt your yagi to 15 degrees and you can work 70% of the amateur radio satellites passes, with your normal azimuth rotator, I did it for ages like that before I got the G5500 AZ/EL rotator.
Yes Robbie.. I did some modelling just the other day.. Low to the ground, my 17 element Tonna would basically give me between about 10 and 80 degrees at good gain.. Next job! (after the next job - after the next job!)
Those lobes and anti-lobes can be a bit of a QSB enabler though as the satellite elevation varies.
I have seen a Band 2 (Broadcast VHF radio) site where it had an omni directional down tilted pattern. 2 vertical dipoles one above the other but fed with a slight phase shift (top antenna fed a few degrees advance of the lower one). Unlike amateur radio they wanted to confine their RF to the local area, but of course the technique could be adapted...
Yes!
Most cellular antennas have a physical down tilt. There can be a fixed tilt or you can install RET units - Remote Electrical Tilt, a motor where you can remotely change the amount of down tilt to "tune" the network.
Talk about turning antenna theory on its head. Fascinating idea to lean the antenna over and improve the gain in the appropriate direction. nice one Cal.
For my money, and from my experience, the hypothesis is true - very true. My DXC Classic is located about 700’ ASL on ground that slants away at about 15+ deg towards Europe/Africa (I’m East Coast US). I’m constantly getting great signal reports with only 100W. I’ve even had some stations question my truthfulness regarding my power and vertical antenna claim.
On yesterday’s live stream (3/10/24) you can hear me at the 48:42 mark with 100 watts into my DXC - a bit over 3500 miles. Nothing special; a 7300 at 100W into the DXC. Needless to say, I’m happy with the performance and believe that the sloping landscape increases my low takeoff angle gain - of sorts. My WSPR plots also validate the increase in reception and signal strength in the direction of the slope.
Oh yes, I found it.. My goodness yes!
Brilliant topic Callum and one i think is fact as my location takes full advantage of this theory. Just a shame behind me is around a 1000ft hill full of iron, although unless it’s all in my head i am almost certain it acts like a huge reflector but predominately in one direction and mainly noticeable on VHF/UHF….Please tell me i am talking out of my backside…🤓
Haha.. You might be right.. The slope will assist.. I remember being told that YEARS ago by folks at the club.. This just explains it better..
Facinating.
Looking forward to the minus Db video, good grief.... I must get a life !
Haha.. Join the club! LOL!!
Hey big guy. Still waiting for you to model a 5/8 over 5/8 over 1/2 wave for 10-11 meters......... 😜. 👍🥃🇦🇺
You and me both!
This is actually a question on the US Amateur Extra exam. (Just passed it last month....humblebrag) Sloping ground will give a lower takeoff angle and more gain, facing downhill.
Well I never knew it was one of the questions! PS - Congratulations!
I remember back in the 1970's/80's going out in the hills and a pre-arranged sked with two stations on 70.260 MHz with my a.m. Pye Bantam with ½ Watt out with a telescopic ¼λ vertical on the Bantam.
I did get a stronger signal on the hillside than at the top. The signal had dropped out by going about 6 feet on the other side but it was quite a steep drop on that side.
G4GHB.
Great memories..
Very interesting - and helpful!
I use a carbon fiber pole to hold my 1/4 wave wire verticals and I run them at about a 5-10 degree slant away from the pole to keep interactions under control. I've been slanting it toward the East. Now I'm going to have to experiment with which direction I slant it.
Great tip!
Ha…I learned something today! This stuff is so interesting. Thank you! 73
Glad to hear it!
The Angle effect is very noticeable when mobile and driving up hill, signals are usually stronger whilst climbing than when on the top of the hill. of course the angle of antenna against the ground or the vehicle is still 90 but something improves that's for sure
It is called knife edge refraction. A well known phenomenon.
Terence llearns more info when you do drawings and sketches
I do a lot of sketches.
Heighty all mighty
very nice
DX Combender
Great video, very interesting and it is great to question how things work and experiment to see how you can maybe improve something. Antennas are equally fascinating as they are to your shack set up.
Big thank you for the mentions, now the lighter evenings are with us i will be making more antennas and experimenting (like my actual extending ladder antenna i did for your competition). All the best, regards Steve aka Enthusiast Steve M6WVV
Hey Steve!
Let’s see the practical side of this. Take two DX Commanders, one straight,one tilted and try making contacts switching between the two.
Please try it.
How do you stop interactions between the two?
I would try it tilted for 10 minutes and straighten it, then try the same contacts again.
I had a 4Square on 20M, on Pamlico Sound, in the water and compared to a guy in CT using 4 over 4 over 4. My 4Sq was always louder, everywhere, all the time.
A 4sq compared to a vertical is like a dipole compared to a 4 ele Yagi.
4sq on 20M are FANTASTIC. Much better than 80 or 40, due to angles and skip zones.
That's amazing!
I have a brand new 4-Sq in the box, ready to deploy from DX Engineering on 40m.. A summer project.
What software are you using?
MMANA.. Search my channel - I made some tutorials.
The "Just 3db more" saga continues 😂
I've wondered about this topic myself. Thanks for explaining it!
HAHA Zach!!
finally finished all the vids phew!
Wow!
Callum please keep feeding chatGPT your antenna science. One day it might be able to build the most perfect antenna for every situation. 👍
Fascinating stuff, thank you ad always for your insight and videos.
Haha! I did try that but ChatGPT had a flaw.. I can't remember exactly the problem.. I think it was impedance matching.
Do you use the DX commander antenna?
I do.. yes.
I'm trying to get my head round that question...
Now that was interesting!
Great topic Callum. - Cheers!
Glad you enjoyed it!
Fascinating stuff. I find this antenna experimentation more interesting than actually talking to anyone 😀
Frankly.. so do I!! :)
Me too. Plenty of slopes around Caerphilly to experiment with. At my "home" GW QTH in the Rhondda, I'm right down the bottom of the valley, but on the western slope. My 80m DX seems to be to the USA though, strangely.
Nicely Done!
Thanks!
Just did this a few days ago as an experiment on a 4th storey balcony with 20degre tilt and tilted radials, folded back at 2meters and linear top loaded to 10m. 1:1.1 and great dx results. Inspired by your explanation of folding and ratios involved.