1. You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
    Dismiss Notice

The AstroPlane Another Viewpoint

Discussion in 'CB Antennas' started by Marconi, Jan 25, 2020.

  1. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

    Joined:
    Oct 23, 2005
    Messages:
    6,207
    Likes Received:
    1,232
    Below is a report on the Avanti AstroPlane antenna done back in the days. I posted some numbers, and some Internet exhibits that claims Avanti professionally tested their AstroPlane (A/P). I did this just for a little history on the AstroPlane.

    I have documents and posted below 2 Eznec models that tend to support Avanti claims...who did the tests, and how it was done. I also provide some verification information on the author of the test report.

    i studied the details of this report and tried to follow the ideas for their construction, so that I could try and duplicate their results.

    So, this is what I hope these models will show us.


    I scaled an old Asto Plane model to 144 Mhz. I started with a model that had a full 1/4 wave radiator. I did this for my convenience in modeling.

    IMO these 2 models tend to support much of what Avanti has claimed in their advertising.

    In the PDF files below is the Avanti's AstroPlane test report, an old ad I found in CB Magazine. I found the Technology News report talking about the Engineer Avanti used to do this research. Followed by the 2 models in the PDF file posted below.

    Sorry for the poor copies, working with old copies of copies is tough. If you can't see something clearly...try using the PDF print. The Zoom functions might help improve the images.

    Models: AstroPlane at 144 MHz set 72" inches to the feed point (1 wavelength high - see the report).

    1. shows the antenna model in Free Space (FS). This means all the ground and wire resistance effects for the model have been removed. This is basically done so we can test the accuracy of the model. See the 1st page of each model, the Eznec Control Panel. At the bottom it shows the Average Gain results (AG). AG results show 1.662 = 2.21 db. In this case the 2.21 db value after the = is a correction value for the gain and is due to an overstated or understated in gain, reported as an error for the model.

    If the value -2.21 db was noted with a (-) then the gain is understated. Then we would add this value to the gain reported by the model. Then, this is consider as the accurate gain for the model.

    If the value 2.21 db, as stated for this model with a (+) that is blank, the gain is overstated and we would subtract the value from the gain reported by the model. Then can consider this is the accurate gain for the model.

    2. shows the antenna over the Eznec feature for Real Earth. This simply means the opposite of FS, where the losses were removed.

    Depending on the sign (+ -), just add or subtract 2.21 db to the gain reported for these 2 models and we will see the accurate gain that the model should report.

    IMO, none of this means the A/P is bad, weak, a dummy load, or is deficient. It is a great antenna and better in other ways that only a few will likely acknowledge.



    Make your own conclusions about the likely gain for the AstroPlane as reported by Avanti advertising and by others making knockoffs of the great vertical 1/2 wave antenna design.
     

    Attached Files:

    #1 Marconi, Jan 25, 2020
    Last edited: Jan 25, 2020

  2. HomerBB

    HomerBB Sr. Member

    Joined:
    Jan 4, 2009
    Messages:
    3,115
    Likes Received:
    911
    357magnum, VoX 997 and Redbeard U812 like this.
  3. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

    Joined:
    Oct 23, 2005
    Messages:
    6,207
    Likes Received:
    1,232
    Homer, thanks for the patent.

    My intention in this thread was to hopefully demonstrate using an A/P model, that was in error, and that error resulted in the gain being overstated. These two models at 144 MHz show gain >4.00 dbi to be overstated similar to what Avanti published in their ads @ 4.46 dbi.

    Homer, I was working on the history of the A/P and I found an old model that showed the gain overstated @ >4.00 dbi.

    I said to myself "WA-LA" maybe this is how Avanti got the big gain they reported for this vertical 1/2 wave antenna.

    I know a 1/2 vertical mono-pole will not produce 4.46 dbi gain. It is closer to 2.14 dbi. It is also my opinion that steering the TO angle of the A/P, if possible other than changes in elevation, those results would be minimal at best, and will only happen in a Free Space model.

    Based on my models, I have never seen an A/P over Real Earth suggesting steering. Avanti is showing us FS models and they tell us "...measurements are given in Figure 1, along with the calculated performance of a 1/2 wave antenna in free space, for comparison"

    Check out the last sentence above Fig 1, in the report I posted in my post #1
    .
     
    #3 Marconi, Jan 27, 2020
    Last edited: Jan 27, 2020
    357magnum and HomerBB like this.
  4. The DB

    The DB Sr. Member

    Joined:
    Aug 14, 2011
    Messages:
    1,799
    Likes Received:
    1,004
    No model over real earth will suggest steering, ever. You have to use free space to see it.


    The DB
     
    357magnum likes this.
  5. VoX 997

    VoX 997 Member

    Joined:
    Jan 23, 2020
    Messages:
    34
    Likes Received:
    27
    So does this new AstroPlane perform like the old one?

    One of my first antennas I used back in the 80s was an old AstroPlane that I got from a family member. That antenna had really good ears and the over all ground noise was really low. I remember being able to pull out stations 60-70 miles away late at night when conditions where calm. It was mounted 25 feet in the air.
     
    357magnum, Woody-202 and Marconi like this.
  6. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

    Joined:
    Oct 23, 2005
    Messages:
    6,207
    Likes Received:
    1,232
    997, welcome to the forum.

    I've had both and I noticed very little difference even when compared TX/RX side by side or with the antennas standing alone.

    I think all of these antennas are difficult to find anymore.

    I also find the Sirio New Top One has a bit wider <2.00:1 SWR bandwidth and within reason the antenna is tune-able.

    IMO these antenna were great.
     
    #6 Marconi, Jan 30, 2020
    Last edited: Jan 30, 2020
    357magnum likes this.
  7. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

    Joined:
    Oct 23, 2005
    Messages:
    6,207
    Likes Received:
    1,232
    DB I agree, I don't see steering of the TOA for my A/P model over real Earth. Currently I don't see steering with my Free Space models either.

    So, does your comment suggest we can seen steering while using an A/P model set in Free Space?

    If so, I sure hope you can find time to use the A/P 4NEC2 code by GHZ24 that I linked for you the other day, and maybe show us a FS model that shows steering or a TOA at or below the horizon or exhibits a tendency to do so.

    Here is what GHZ24 said about all of the models he posted back then.

     
    #7 Marconi, Jan 30, 2020
    Last edited: Jan 30, 2020
    VoX 997 and 357magnum like this.
  8. 357magnum

    357magnum Sr. Member

    Joined:
    Feb 25, 2014
    Messages:
    1,916
    Likes Received:
    2,179
    Welcome Vox ! (y) Don't be a stranger . This is the place for info .(y) Iv'e been doing it over 50 years & still learning . Thanks again Marconi " Oh Antenna God " :D
     
    VoX 997 and Marconi like this.
  9. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

    Joined:
    Oct 23, 2005
    Messages:
    6,207
    Likes Received:
    1,232
    Keep me posted on the 2m V4K.
     
    HomerBB and 357magnum like this.
  10. The DB

    The DB Sr. Member

    Joined:
    Aug 14, 2011
    Messages:
    1,799
    Likes Received:
    1,004
    Yes, but as I recall it took quite a big change for a rather small amount of steering. I modified the model as per the patent, and only saw a difference of 4 or 5 degrees.

    I have been working long hours for a while, and will be for the foreseeable future. If you want to see this done, you are going to have to do it yourself. Besides, if I were to play with an Astroplane model I would make my own. Nothing against ghz24, his models are great starter models, but I prefer my own work. So please stop asking me to use someone else's models. Without good reason, its simply not going to happen.


    The DB
     
  11. Marconi

    Marconi Usually if I can hear em' I can talk to em'.

    Joined:
    Oct 23, 2005
    Messages:
    6,207
    Likes Received:
    1,232
    That's okay DB, but you tell us all of your 4NEC2 models were lost in a computer failure. So, I was thinking his code might be helpful in getting a bases to start and then you could modify the model as you wished.

    Nothing sinister going on DB, I was just trying to share.
     

Share This Page

  • About Us

    The WorldwideDX Radio Forum was originally established in 2001. We pride ourselves on welcoming Radio Hobby enthusiasts of all types, while offering unbiased, informative, and friendly discussion among the members. We are working every day to make sure our community is the best Radio Hobbyist's site.
  • Like us on Facebook

  • Premium VIP Member

    The management works very hard to make sure the community is running the best software, best designs, and all the other bells and whistles. Care to buy us a beer? We'd really appreciate it!

    Donate to us!