Project : HLine3D = a Build Your Own 21cm Hydrogen Line Radio Telescope System

[Alex_Fla]

Hello All,

This may be of interest ..

The development of this has been ongoing for 10+ months.

 

It is designed to be an appropriate project for a high school or undergrad college student

 

Hardware : The Circular Patch Feed Disk Yagi antenna is easy to fabricate with hand tools and has excellent performance

Software:   The Spectral Processing involves only 3 steps making it easy to comprehend and offers many 2D/3D Graphic Display options.

 

Note :

The amplitudes are Calibrated in dB referenced to  Cold_Sky.

Meaning :   The plots can be used to compare different configs or one system with another

 

"  HLine3D  "  can now be found using most search engines

 

https://github.com/AP-HLine-3D

 

Best Regards,

Alex Pettit

Winter Springs Fla USA

=====================

 

[robin_astro]

There was a Hydrogen line build project using a 45 element Yagi here

but ultimately later in the thread it evolved into a 1.2 m offset dish which proved more effective (higher gain and less ground noise)

 

Cheers

Robin

[Alex_Fla]

 Robin,

I received this info from a PhD who has extensively NEC modeled and tested many Yagis for the UHF/Microwave range

" Many many years ago I built the G3JVL yagi antenna.
Used in many contests. Seen many sidelobes, some very large.
Rather low gain 15dBi, quite inefficient, but somehow works.
I do not recommend this chicken-foot antenna to anyone.
Please see the attached results, Matjaz "

I

[robin_astro]

Ha !  That probably explains why, despite its enormous length it proved rather ineffective.  The history of amateur radio is littered with such devices  🤣

Robin

G8DVW

[Alex_Fla]

Robin,

If you have an interest, there is a fairly lengthy *.pdf documenting the NEC Analytical Modeling and Field Test Validation of this Circ Patch Feed Disk Yagi.

This project is based on the work of Dr Vidmar ( whose comment  regarding the Loop  is posted above )

Cheers, Alex  KK4VB