Everyone says 59 copy even if you are barely readable. It's amazing how many times I hear someone say they are 59 and keep asking them to repeat what they said.
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ASTROPLANE best vertical antenna ever?
- Thread starter nosepc
- Start date
I'm not 5-9. I'm 5-7, but what does my height have to do with anything..?
I loved your post, Homer, but have to disagree.
We've talked via DX conditions, and though it's been a couple years since our contact on Lsb-38, I recall you were 5 OVER. 9.
I was standing on a bucket that day.I loved your post, Homer, but have to disagree.
We've talked via DX conditions, and though it's been a couple years since our contact on Lsb-38, I recall you were 5 OVER. 9.
Have read the topic a little bit. Have made an astroplane for the 70cm. lol
Now a double astroplane made with stub.
Upload a lot of photos.
https://www.qrz.com/db/PD0G
https://pd0g.wordpress.com/
Upload a lot of photos.
https://www.qrz.com/db/PD0G
https://pd0g.wordpress.com/
Now a double astroplane made with stub.
Upload a lot of photos.
https://www.qrz.com/db/PD0G
https://pd0g.wordpress.com/
Upload a lot of photos.
https://www.qrz.com/db/PD0G
https://pd0g.wordpress.com/
Putting a set of radials below the basket area? That thought hadn't occurred to me... Lets play...
Doing some initial modeling, I got a some amount of additional gain by adding radials and putting them 51.5 inches below the ring (dimension for CB sized antenna, not the 70 cm version with radials shown above). This distance was the distance that gave me the best results...
Now I haven't played with this model much, so I am not sure if the benefit of adding radials has to do with the mast length (that goes all the way to the earth below the antenna in the radials model). I have not yet looked at this antenna with other mast lengths or antenna heights. However, for those who would have issues isolating a mast at a given location for optimal performance, adding a set of radials at a specific location *might* be an alternate solution...
Unfortunately I don't have time to play with this idea at the moment...
The DB
A few days ago I was talking to bob85 about the Vector antenna and the ability to steer where the signal goes in freespace models. The Astroplane patent also refers to this concept, so I am looking to put that to the test.
So according to the patent, changing the diameter of the ring, and the adjusting the elements that support the ring to compensate, you can change the "take off angle" of this antenna. In reality, the "take off angle" will not change as in the presence of an earth the earth and the height of the antenna above said earth are what actually controls said "take off angle". However, is it possible to control the antenna's angle of radiation before the earth is in play? The quote above from the patent suggests that this is a possibility.
To start with, we model the Astroplane antenna in freespace.
Here we can see that peak gain is actually at a downward angle. When it comes to local communications, this would be a benefit as it is pushing its signal down towards the earth, instead of straight out or angled upwards like many other antennas.
In one model I added five inches to the ring radius, and in another I made the radius 5 inches shorter. I did some modeling of ring sizes within this range as well, but those are not shown here. Here is a comparison of the three models.
The sr model (in green) used the smaller ring, and the lr model (in blue) used the larger ring.
As we can see, the results are very similar, even with such a large change to the ring diameter. This likely is because the ring does not carry much current, and includes a current null as well. Because of this it takes a larger change to to this area of the antenna to affect the radiation pattern of the antenna than if a current node or higher current was present on said portion of the antenna.
I was able to achieve said RF steering with these changes, however, as we see their isn't much of a difference. Adding five inches to the radius was able to steer peak gain up by one degree, and removing five inches from the radius was able to steer peak gain down by a degree. On its own I would say that such a large change to the antennas dimensions for such a small change when it comes to the radiation pattern on makes this, as far as rf steering goes, a pointless endeavor. However, that is not all that is in effect in these models.
The larger ring, in addition to steering rf up a degree, also increased the antenna's peak gain. This change in gain was enough that despite the angle of peak gain being further away from a desired angle pointing further down for local contacts, their is actually more gain pointed at said lower angles.
That was definitely not what I expected.
This is a preliminary result, however, it is suggesting that using a larger ring, and shortening the elements that connect said ring to the antenna to compensate, actually increases both the local and DX potential of this antenna.
Anyone want to try this out with a real world test?
The DB
Astroplane Patent said:
So according to the patent, changing the diameter of the ring, and the adjusting the elements that support the ring to compensate, you can change the "take off angle" of this antenna. In reality, the "take off angle" will not change as in the presence of an earth the earth and the height of the antenna above said earth are what actually controls said "take off angle". However, is it possible to control the antenna's angle of radiation before the earth is in play? The quote above from the patent suggests that this is a possibility.
To start with, we model the Astroplane antenna in freespace.
Here we can see that peak gain is actually at a downward angle. When it comes to local communications, this would be a benefit as it is pushing its signal down towards the earth, instead of straight out or angled upwards like many other antennas.
In one model I added five inches to the ring radius, and in another I made the radius 5 inches shorter. I did some modeling of ring sizes within this range as well, but those are not shown here. Here is a comparison of the three models.
The sr model (in green) used the smaller ring, and the lr model (in blue) used the larger ring.
As we can see, the results are very similar, even with such a large change to the ring diameter. This likely is because the ring does not carry much current, and includes a current null as well. Because of this it takes a larger change to to this area of the antenna to affect the radiation pattern of the antenna than if a current node or higher current was present on said portion of the antenna.
I was able to achieve said RF steering with these changes, however, as we see their isn't much of a difference. Adding five inches to the radius was able to steer peak gain up by one degree, and removing five inches from the radius was able to steer peak gain down by a degree. On its own I would say that such a large change to the antennas dimensions for such a small change when it comes to the radiation pattern on makes this, as far as rf steering goes, a pointless endeavor. However, that is not all that is in effect in these models.
The larger ring, in addition to steering rf up a degree, also increased the antenna's peak gain. This change in gain was enough that despite the angle of peak gain being further away from a desired angle pointing further down for local contacts, their is actually more gain pointed at said lower angles.
That was definitely not what I expected.
This is a preliminary result, however, it is suggesting that using a larger ring, and shortening the elements that connect said ring to the antenna to compensate, actually increases both the local and DX potential of this antenna.
Anyone want to try this out with a real world test?
The DB
To start with, we model the Astroplane antenna in freespace.
DB, what does this FS antenna look like?
How did you handle the mast inside the antenna for this Free Space model that generated this pattern?
Its the same model I used before, the one with the optimal length isolated mast. I forget the dimensions offhand and am out camping at the moment, so if you need specific dimensions let me know and I'll get them to you when I get back home.
The DB
DB, my Old Top One model shows what I consider a more traditional Free Space pattern and I can't explain the difference from your model.
Here is the A/P pattern in the Patent 3.587.109 which shows a similar tilt for the lobes. Neither pattern resembles your model.
This is not to suggest that a modified antenna of this type can't be made to show different results.
Here is the A/P pattern in the Patent 3.587.109 which shows a similar tilt for the lobes. Neither pattern resembles your model.
This is not to suggest that a modified antenna of this type can't be made to show different results.
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