Hello I would prefer the 500 HZ 6.3 MHZ, because the PBT is working on 6.3 Next would be 500 9 MHZ and next 250 9 MHZ I have all filters in my OMNI 6+ Cascading the 6.3 and 9 MHZ is a very big improvement in selectivity 73 de Harry, DK2GZ --- StripMime Report -- processed MIME parts --- multipart/alternative text/plain (text body -- kept) text/html ---