Microwave antenna - Page 1
Forum section: electronics / rf-microwave

author: mattko
author_rank: Contributor
timestamp: May 06, 2020, 12:24:59 pm
content: Hello,I'm wondering what is the internal structure of a microwave antenna. Example in the attachment.I tried with google, but it does not seem to be available.Anybody has some info?

author: coppercone2
author_rank: Super Contributor
timestamp: May 06, 2020, 11:03:44 pm
content: here it ishttps://www.crtfrance.com/en/wlan-wimax-system/751-sdc-24-15-sirio.html

author: radioactive
author_rank: Regular Contributor
timestamp: May 07, 2020, 12:07:59 am
content: In the past I worked a job where I traveled to many "repeater" sites. I always wondered the same question. After many years as an RF design engineer, I still have never put anything that I designed on a hill with one of those "drum" antennas, so your question is interesting to me.I don't know the actual answer, but I think what you will probably find is that there is a variety of different antenna structures in those drums? I hope someone else with first-hand knowledge will expand on this.Even with various antenna structures like Dipole, Co-linear Dipole, Yaggi (more likely), panels, etc it does seem that this "drum" structure would still provide some some extra shielding from nearby shitstorms that are on top of the most popular hills.Looking forward to being schooled on this subject.

author: radiolistener
author_rank: Super Contributor
timestamp: May 07, 2020, 12:13:36 am
content: probably something like this:or like this:or like this:

author: xmo
author_rank: Regular Contributor
timestamp: May 07, 2020, 12:24:32 am
content: It's just a big point-to-point dish with cover to keep stuff out.Download the Andrew catalog. There's lots of information in there.https://www.jmu.edu/wmra-eng/archive/AndrewCatalog38.pdf

author: coppercone2
author_rank: Super Contributor
timestamp: May 07, 2020, 12:47:36 am
content: Quote from: xmo on May 07, 2020, 12:24:32 amthat catalog is a beastanyone feel like a peon after looking through that?

author: eb4fbz
author_rank: Regular Contributor
timestamp: May 07, 2020, 09:38:33 pm
content: They are just a parabolic dish antenna with a shielding ring to reduce sidelobes and a fiberglass radome to protect against weather and wild life.

author: 1design
author_rank: Regular Contributor
timestamp: May 08, 2020, 02:02:00 pm
content: We deployed over 100 of these, from the tiny 3ft ones to the larger 10 and 12 footers.As mentioned before, they are just parabolic dishes, they have to be assembled on site/in a warehouse.The feed is a single or dual waveguide, depending if the dish is single or dual polarization.As a point of interest, the radiation pattern is not exactly symmetrical and there is a marker on one of the waveguides, showing which side has better rejection.The "drum" is called the radome and is there for side lobe reduction, the inside is covered with RF absorber, as is the feed line/feed horn. The front is a canvas, held in place by screw/spring tensioners.The feed horns/lines can be replaced, for this, the front canvas is removed and the feed suspenders are loosened, it is an interesting operation. Hanging in front of a 10ft dish 400ft up in the air while manipulating the 5ft feed horn in and out through the front of the dish.Here you can see the entire process of assembly with every component being visible:https://www.youtube.com/results?search_query=HX6%2FUSX6+AntennasHopefully this answers your question.

author: radioactive
author_rank: Regular Contributor
timestamp: May 11, 2020, 02:07:37 am
content: Thanks!