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RG-174/U loss
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RG-174/U loss

by mateskelin on Fri Jan 11, 2019 11:33 am

Hi!
I am interested in RG-174/U cable as it is wery thin, but what is the loss of cable in dB/m at 1GHz and 2GHz ? There is no mandatory data for coax cable.
https://www.adafruit.com/product/2059

mateskelin
 
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Re: RG-174/U loss

by dlleigh on Fri Jan 11, 2019 11:44 am

A google search will find you the attenuation. This is the first thing that a search pulled up for me: https://www.w4rp.com/ref/coax.html

RG-174 is not meant for use at such high frequencies: it's pretty lossy up there.

Please tell us more about your application so that we can help you find something appropriate. Information about the frequencies in question, the length of the run, the type of environment, what's on either end of the coax, the amount of power you intend to run, etc. would be helpful.

dlleigh
 
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Re: RG-174/U loss

by mateskelin on Fri Jan 11, 2019 11:58 am

I need coax with max. diameter of 1.2mm for frequency up to 2GHz. Loss should be as good as it gets with this diameter...
Both ends of coax will be solderd directly to PCB. Max. power will be 2W.
thanks for reply!
Last edited by mateskelin on Fri Jan 11, 2019 1:45 pm, edited 1 time in total.

mateskelin
 
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Re: RG-174/U loss

by dlleigh on Fri Jan 11, 2019 12:14 pm

OK. Note that RG-174 has an outer diameter of 2.8 mm, not 1.2. I don't know what Adafruit is selling, but either the type (RG-174) or the stated diameter (1.2 mm) is incorrect.

Coaxial cable with a 1.2 mm diameter (0.047 inches) is available. This is semi-rigid coax and is expensive. Pasternack sells two kinds for about US$11 per foot. The attenuation is about 1.3 dB/m at 1 GHz, and it will easily handle 2 watts of power.

If you want lower attenuation than that, you'll have to go to a thicker cable. Also note that 75 ohm coax tends to have somewhat lower attenuation that 50 ohm.

dlleigh
 
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