Astrobeam

[RT2020]

I was kinda thinking the dual 59u would maybe make 35 ohms but was un clear, thanks.

 

[RT2020]

Forgot to answer your question, yes it has a male on one end and a female on the other.

 

[Marconi]

Here is my Eznec model of the Astro Beam to specs, and then modified to resonance and isolated from the Earth.

The first model to specs and has a 77.625" radiator as noted in the manual. This model is connected to the Earth as recommended.

The second model is modified. The mast is isolated (ISO) from the Earth by 1' foot, and the radiator is made 86" long in order to reach resonance which is very similar to what I found when making my AstroPlane with a full 1/4 wave radiator at 87.5" to resonance.

View attachment AstroBeam to specs and modified..pdf

 

[Marconi]

I used my MFJ 259B to tune and as per manual with the stock length on the driven stinger of 77 5/8" it was resonant at 26.025. I am looking for the 11 meter band.

2020, as noted above I just modified my Eznec model for the Astro Beam to specs, and it too shows the radiator needs to be very near the 87.5" where I found resonance on my modified real world Astro Plane...when I use a full 1/4 wave radiator instead of the shortened radiator and the top hat setup.

Plus according to your post above you will need to go even shorter, and that just doesn't make sense. The A/P has a very large diameter hoop/radial setup at the base, and that will likely show the physical length somewhat shorter at resonance compared to a nearly 17+' foot dipole or yagi element.

Could something be wrong in your report above.

When I made my A/P radiator 77.625" inches the resonance was up in the 28 mhz area, just as I might expect.

Did you keep some notes or can you give me some details regarding how you used your 259B that showed your results? I'm just curious to find out what is wrong here. I promise not to try and give you guys a lesson on using your analyzers.

 

[RT2020]

You know what I did not make notes and I always tell myself that I need to do that next time and I never do. I could be wrong and I will work on it this weekend if I do not have to work and I will post the results, I promise I will take notes this time..lol

 

[Marconi]

You know what I did not make notes and I always tell myself that I need to do that next time and I never do. I could be wrong and I will work on it this weekend if I do not have to work and I will post the results, I promise I will take notes this time..lol

Here are the notes for the 3 tuning reports on my AstroPlane with a full 1/4 wave radiator. The top numbers are using my analyzer and the bottom is using my inline SWR meter.

View attachment AstroPlane bandwidth and tuning,.pdf

Whenever you get the time, thanks.

 

[RT2020]

Good stuff Marconi, very thorough and I imagine time consuming but well worth by the looks of your worksheets.

 

[RT2020]

Also I see you say in the model you isolated the mast but I am unclear how I would do that with a tower install. Just cant wrap my head around that.

 

[2RT307]

Glad to see you bringing the old Astrobeam back to life, Greg.

73,
RT307

 

[RT2020]

Well you dont seem to want to let go of yours....lol

 

[RT2020]

Here she was in all her glory when I had it up before.

 

[Marconi]

Also I see you say in the model you isolated the mast but I am unclear how I would do that with a tower install. Just cant wrap my head around that.

I never isolated my A/P or a model of my A/P before today. I did isolated (ISO) my Astro Beam model today at the suggestion of Bone Stabber over on Mauldroppers. I was curious about the idea and why he made the claim, so I tried in on the model and posted the results. I was surprised.

 

[Marconi]

Here she was in all her glory when I had it up before.

Very nice looking setup and it looks plenty high. I sure wouldn't want even a short 4" insulator trying to support that above the rotor.

 

[RT2020]

I definitely do not recommend putting the rotor that way, I have learned a couple things since then...lol

 

[Lil'Yeshua]

Avanti AV-150 "Astro-Beam"