Understood this video is 4 years old. Most plastics need UV protection, otherwise they decay pretty rapidly. I would have suggested to take the milk jug, paint it with the paint you planned on using, and see whether it increases attenuation. 73, Bert VE2ZAZ / VA2IW
The reason they don't cover it is because the dielectric constant of the materials will behave like a superstate. In the way you measured the plastics here I would suspect that the plastic were behaving like a dielectric lens or superstate depending on the near-field/fresnol zone of this particular horn. In other words, your'e measuring the path loss in a magnetic field dominant zone while if you placed it just a few cm away from the mouth of the horn you will be measuring the loss in an electric field dominant zone. Not sure if this will produce different results for this test case but I would argue that a spot check wouldn't hurt.. :)
Hello and TU for your comments. Very interesting. I had assumed because my RX probe was ~20 wavelengths away from the source I would be measuring the planewave and not just the E or H-field. I have some horn antennas for 10 GHz (standard gain types) that are covered by a thin fiberglass sheet. The reason I had to find a cover is because my dish & feed will be up in the air about 60' and wanted to ensure rain, snow, ice, dust, dirt, spiders and bees stay out of the feed.
Well we all know what even a little bit of water will do LOL......just look at the IL as I move my fingers in front of the beam path. Still, for you I will do it for S&G's.
Sorry I just saw your question. For some reason notifications were turned off and I never knew you posted. If you look at the SA screen you can see it was set for 1 dB/div. 73
Very interesting. Useful information. Dave N9HF
Great info, Gedas, and timely as I am about to do the same thing. Don’t want to have feed problems at 110 feet!
Hiya Rus. Glad the video is timely. I think I am going to try some etched fiberglass PCB material next.
Understood this video is 4 years old. Most plastics need UV protection, otherwise they decay pretty rapidly. I would have suggested to take the milk jug, paint it with the paint you planned on using, and see whether it increases attenuation. 73, Bert VE2ZAZ / VA2IW
For sure. Most plastics are not made for outdoor use and break down pretty quick. 73
The reason they don't cover it is because the dielectric constant of the materials will behave like a superstate. In the way you measured the plastics here I would suspect that the plastic were behaving like a dielectric lens or superstate depending on the near-field/fresnol zone of this particular horn. In other words, your'e measuring the path loss in a magnetic field dominant zone while if you placed it just a few cm away from the mouth of the horn you will be measuring the loss in an electric field dominant zone. Not sure if this will produce different results for this test case but I would argue that a spot check wouldn't hurt.. :)
Hello and TU for your comments. Very interesting. I had assumed because my RX probe was ~20 wavelengths away from the source I would be measuring the planewave and not just the E or H-field. I have some horn antennas for 10 GHz (standard gain types) that are covered by a thin fiberglass sheet. The reason I had to find a cover is because my dish & feed will be up in the air about 60' and wanted to ensure rain, snow, ice, dust, dirt, spiders and bees stay out of the feed.
Great video, next time u setup try glass fill up a baggy with water and see how it reflects ?
73 N8AUM
Well we all know what even a little bit of water will do LOL......just look at the IL as I move my fingers in front of the beam path. Still, for you I will do it for S&G's.
@@w8bya G tnx !
Is your vertical scale set at 1db or 2db per division?
Sorry I just saw your question. For some reason notifications were turned off and I never knew you posted. If you look at the SA screen you can see it was set for 1 dB/div. 73