At 1/11/2009 06:12, you wrote: >Correct, here is the order info sheet from the wayback machine.... >73, Joe, K1ike
OK, is it just me or is there NO noise figure spec. in any of these documents? My guess is that the GLB preselector consists of the filter followed by the preamp. Also because of the number of sections of filtering & the overall small size of the unit, the actual helical filter is probably quite lossy. For comparison the 5 section helical resonator in the front end of the G.E. Mastr II/MVP VHF HB radio has about 6 dB of loss. If you need preselection and low noise figure, I'd look here: <http://anglelinear.com/custom/custom.html> or do what I do & look at the hamfests or eBay for one or two 1/4 wave bottles followed by the preamp of your choice. Pass cavities are typically 0.5 to 1 dB loss. The Angle Linear cans are even lower - I measured 0.25 dB on one of his 220 MHz filters. Bob NO6B
