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Electronics => Projects, Designs, and Technical Stuff => Topic started by: mrpackethead on September 26, 2017, 03:15:36 am

Title: What kind of antenna is this.
Post by: mrpackethead on September 26, 2017, 03:15:36 am
Can any one tell me what kind of antennas these are?   They are for 900Mhz..   
Title: Re: What kind of antenna is this.
Post by: T3sl4co1l on September 26, 2017, 03:39:55 am
Probably https://en.wikipedia.org/wiki/Collinear_antenna_array
Title: Re: What kind of antenna is this.
Post by: bjcuizon on September 26, 2017, 04:45:04 am
Quote from: T3sl4co1l on September 26, 2017, 03:39:55 am
Probably https://en.wikipedia.org/wiki/Collinear_antenna_array
Yup, probably for gsm/mobile com antenna arrays.
Title: Re: What kind of antenna is this.
Post by: hcglitte on September 26, 2017, 07:35:19 am
To me they look like end fed half wave dipole antennas.
Title: Re: What kind of antenna is this.
Post by: LukeW on September 26, 2017, 11:27:56 am
Are the wider cylindrical pieces 80mm long, or so?

It just looks like a good old half-wave dipole.
Title: Re: What kind of antenna is this.
Post by: cdev on September 29, 2017, 05:56:24 pm
I think it may be a collinear but because the gaps between the wider sleeves, are not 100% consistent with what I would expect, its hard for me to say 100% unless you can give us images with more detail.

The closer images look more like sleeve dipoles, the ones in the upper rear part of the picture are more likely collinear. Its probably collinear.


Title: Re: What kind of antenna is this.
Post by: mrpackethead on September 29, 2017, 06:07:23 pm
Im guessing i'm going to have to pull apart the antennas i have to find out for real! these pics are taken from a factory in china...
Title: Re: What kind of antenna is this.
Post by: PA0PBZ on September 29, 2017, 06:29:30 pm
Looks like stacked dipoles, the bigger parts do seem to have a hole or even a circle around them in the middle.
Title: Re: What kind of antenna is this.
Post by: cdev on September 29, 2017, 06:40:53 pm
This is a coaxial collinear antenna, you can see the difference-
http://www.nodomainname.co.uk/Omnicolinear/2-4collinear.htm (http://www.nodomainname.co.uk/Omnicolinear/2-4collinear.htm)

Its likely possible to make one with sleeves, but its not so clear to me yet how they'd handle phasing...

does anybody know?