At 7/31/2010 06:58, you wrote: > Hello Bob, > >I agree that the GLB is a space saving device, but don't you think that >the multistage helical coil stages in the preselector with beat a single >cavity in skirts and out-of-band rejection?
No. There is a compromise in that although the out of band (OOB) rejection looks really good, there is a caveat in that the active device in the preselector is NOT behind that selectivity curve. As Skipp points out, the filtering is distributed before & after the preamp. Since we have no idea what that distribution is, the actual dynamic range of the preselector as a function of frequency is unknown. It does provide a lot of OOB rejection to the RX to connect it to, but you have to hope that the active device in the preselector isn't getting clobbered. Add to that the unknown NF, which is going to set your system NF, & I conclude there are just too many unknowns in this beast to recommend it. Sure it works for many, but it's by chance, not by engineering. Bob NO6B
