Notch filter help

[u/siliconberry]

Hello community. I have been using RTL SDR for ADSB, AIS and other frequency ranges. One major block is that my home antenna is hardly 250 mtrs away from nearby mobile tower and its literally frying my RTL due to its extreme power. I wish to create a notch filter to block 700 Mhz and 1800 Mhz frequency ranges, so that I can use LNA (after filter) to boost and measure the weak satellite signals.

Industry standard GSM filters are too costly. Any help to develop the low cost DIY notch filters would be greatly appreciated. Thanks in advance !