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Electronics => Projects, Designs, and Technical Stuff => Topic started by: Pack34 on November 21, 2016, 10:14:00 pm

Title: Antenna wire length limit for Bluetooth
Post by: Pack34 on November 21, 2016, 10:14:00 pm
Right now I'm attempting to source an adhesive bluetooth antenna with a 200-mm wire. Due to mechanical limitations this will be the best placement for this.

I'm seeing a fair amount of 100-mm or less. Does the antenna cable itself need to be less than the wavelength of the signal?
Title: Re: Antenna wire length limit for Bluetooth
Post by: Pack34 on November 21, 2016, 10:28:18 pm
I'm attempting to find one of these with a length of 200-mm
http://www.digikey.com/product-detail/en/taoglas-limited/FXP70.07.0053A/931-1074-ND/2332701 (http://www.digikey.com/product-detail/en/taoglas-limited/FXP70.07.0053A/931-1074-ND/2332701)

I was able to find this Molex one, but it looks like it'll be just a hair too short. I think I really need 200-mm.
http://www.digikey.com/product-detail/en/0479501011/WM5032-ND/2709380 (http://www.digikey.com/product-detail/en/0479501011/WM5032-ND/2709380)

Can anyone help me out?
Title: Re: Antenna wire length limit for Bluetooth
Post by: Monkeh on November 21, 2016, 10:38:34 pm
What's wrong with this? http://www.digikey.com/product-detail/en/molex-llc/0479502001/WM5030-ND/2709378 (http://www.digikey.com/product-detail/en/molex-llc/0479502001/WM5030-ND/2709378)

Or this: http://www.digikey.com/product-detail/en/molex-llc/0479502011/WM5033-ND/2709381 (http://www.digikey.com/product-detail/en/molex-llc/0479502011/WM5033-ND/2709381)

Or something else from the 109 2.4GHz antennas with 200-300mm tails: Long URL here (http://www.digikey.com/product-search/en/rf-if-and-rfid/rf-antennas/3540022?FV=9340235%2C9340237%2C934023c%2C9340245%2C9340249%2C934024a%2C934024b%2C9340254%2C934025a%2C934025b%2C9340266%2C9340268%2C934026a%2C934026e%2C934026f%2C9340275%2C934027a%2C9340285%2C9340287%2C9340288%2C934028a%2C9340293%2C9340294%2C9340295%2C9340296%2C9340297%2C9340298%2C9340299%2C934029a%2C93402b3%2C93402b8%2C93402c4%2C93402c5%2C93402ca%2C93402cb%2C93402cc%2C93402ce%2C93402d3%2C93402dc%2C93402e1%2C93402e5%2C93402e7%2C9340300%2C9340301%2C9340304%2C9340305%2C9340309%2C934030a%2C934030b%2C9340311%2C9340312%2C934031b%2C934031e%2C934031f%2C9340329%2C9340330%2C9340331%2C9340332%2C9340347%2C934034b%2C934034c%2C9340363%2C9340367%2C934036a%2C1ce80003%2C1ce80006%2C1ce80008%2C1ce80009%2C1ce80010%2C1cec0043%2C1cec0045%2C1cec0046%2C1cec0049%2C1cec004a%2C1cec004b%2C1cec01ce%2Cfff40036%2Cfff80436&mnonly=0&newproducts=0&ColumnSort=1000011&page=1&stock=0&pbfree=0&rohs=0&quantity=&ptm=0&fid=0&pageSize=25)

Quote from: blueskull on November 21, 2016, 10:20:13 pm
Quote from: Pack34 on November 21, 2016, 10:14:00 pm
Does the antenna cable itself need to be less than the wavelength of the signal?

No. In fact, many antenna cables in laptops are longer than 200mm.
However, the longer the antenna is, the more loss it is going to attenuate.

Surely if you attenuate loss, you gain?
Title: Re: Antenna wire length limit for Bluetooth
Post by: Pack34 on November 21, 2016, 10:47:26 pm
I... completely missed those.

Thanks!
Title: Re: Antenna wire length limit for Bluetooth
Post by: Zero999 on November 21, 2016, 10:50:04 pm
Quote from: Monkeh on November 21, 2016, 10:38:34 pm
Quote from: blueskull on November 21, 2016, 10:20:13 pm
Quote from: Pack34 on November 21, 2016, 10:14:00 pm
Does the antenna cable itself need to be less than the wavelength of the signal?

No. In fact, many antenna cables in laptops are longer than 200mm.
However, the longer the antenna is, the more loss it is going to attenuate.

Surely if you attenuate loss, you gain?
He meant, the longer the cable, the more the signal will be attenuated.
Title: Re: Antenna wire length limit for Bluetooth
Post by: Monkeh on November 21, 2016, 10:50:40 pm
Quote from: Hero999 on November 21, 2016, 10:50:04 pm
He meant, the longer the cable, the more the signal will be attenuated.

You know, I can figure that out.