[Hackrf-dev] Please help to calculate the correct attenuator for my GSM antenna

Paul Connolly eeipcy at gmail.com
Wed Jul 15 16:06:30 EDT 2015


Since no one on earth is in the same RF environment as you, no one can
tell you exactly how much attenuation (if any) you will need. You could
be living 50 feet away from a GSM base station, or FM transmitter, for
all we know. Start out with large attenuation (70dB) and reduce the
attenuation until you see a signal is what I would do.

Damage is more likely to come from a local RF sources (Mobile phone
sitting on top of a HackRF) than some distant source due to the inverse
square law. https://i.stack.imgur.com/VEbep.gif

On 15/07/2015 17:35, Johan Nel wrote:
> Hi,
>
>  
>
> Please could someone assist me with this. I'm not at all familiar with
> electronics. My interest is programming.
>
>  
>
> I have purchased the following GSM antenna:
>
> 4G Multiband High Gain Omnidirectional Antenna (Multi Band Dipole Array)
>
> 50 Ohm Impendence
>
> 5 to 6 dBi gain (depending on the band)
>
> Max input power - 20 Watts (for GSM 900 and LTE 800), 10 Watts (for GSM 1800
> and UMTS)  and 6 Watts (for WLAN and LTE 2600)
>
> 5 meter low loss cable with a SMA male connector
>
>  
>
> I understand that the HackRF has a max RX of -5 dBm and its recommended is
> to fit an attenuator to prevent the risk of damage.
>
>  
>
> Please could you assist me in calculating the correct attenuator I should be
> using to protect my HackRF from permanent damage, using this antenna.
>
>  
>
> Many thanks and regards,
>
> Johan Nel.
>
>  
>
>
>
>
> _______________________________________________
> HackRF-dev mailing list
> HackRF-dev at greatscottgadgets.com
> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev

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