Testing a 500 mHz Low Pass Filter To Block Out Strong 700 mHz LTE Interference

My residence is located extremely close to a cellular tower. Full strength LTE indoors and outdoors is great for my smart phone, but not so great for my radio hobby.

This particular cellular tower is operated by Telstra and uses two LTE bands, 1800 mHz (DCS Band 3) and 700 mHz (APT Band 28) The 1.8 gHz LTE doesn't seem to affect my Airspy R2 since technically, it is outside of the SDR's receivable frequency range.

700 mHz on the other hand is overloading my SDR's receiver and causing the noise floor to jump up and down at various places in the spectrum, military airband and 460 mHz UHF to name a few. This makes it hard to decode weak digital voice modes such as TETRA.

I purchased a Crystek CLPFL-0500 Inline 500 mHz Low Pass Filter in the hope it would attenuate the LTE signal and prevent front-end splattering of my SDR's. I am happy with the result, but obviously this isn't a perfect solution as now I am prevented from receiving anything meaningful above 500 mHz.

An 800 mHz notch filter with about 100 mHz of stop-band bandwidth would be perfect. If anyone knows if these exist, or how to homebrew one, please let me know! Thanks.

Тэги:

#Software_defined_radio #sdr #airspy #r2 #sdr_sharp #SDR# #SDRSharp #low_pass_filter #LPF #500_mhz #interference #lte #700_mhz

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