I finally broke down and bought a filter. I just installed it at my Beast and have noticed a significant increase in the message rate - at least 200 messages per second. I'm up to 600 Mode-S and 2384 Mode-A/C at the moment. Just my initial observation.
I'm about 20 miles south of KLAX.
Mark
I have one of the DPD 1090 antennas, but I haven't had a chance to put it up yet. To be honest, I've had little interest given the ever-changing weather and the fact that all I have to monitor with right now is a E4000-based dongle. I'd like to get the Beast or the Transponder Mouse, but they apparently don't want to make it easy for anyone to buy them.
Maybe once I get the antenna up and it reveals how bad my current 2m/440 mhz dual band vertical is for ADS-B, I might become more enthusiastic.
I also have both a Stridesberg multicoupler and a Par TV filter, and both of them claim upper limits of 1 Ghz. i'm wondering if I'm losing out having them inline.
Mike