Re: 3D printed cassegrain reflector.


Colin G4EML
 

With todays slightly warmer weather I have been doing some initial tests outdoors with the 3d printed and copper plated cassegrain reflector and 18" Edmund dish on 122GHz. 
The results look very encouraging. Adjustment of the reflector shows a well defined peak in gain when the tip of the reflector is in line with the face of the dish. Which I think is what was intended in Neil's calculations. 
Adjustment of the feed horn does not seem to be anywhere near as critical, I have ended up with it protruding from the rear of the dish by about 5mm. 

This is giving me a Very sharp beam with only one well defined peak.  

My test source is just an RF Explorer signal generator at 4.9Ghz feeding about +10dBm into a diode soldered across the end of a short piece of semi rigid to generate the 25th Harmonic. I can detect this at about 20dB over the noise level a range of 10m.  I will try to do some comparison tests with other antennas later in the week if the weather stays OK. 

Colin G4EML




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