Hi all:
The notation below (previously posted) is referring to the final passband filter and NOT a roofing filter. You are trying to compare apples and oranges. I think you would be hard pressed to discern (in real use) a difference between the 200 and 250 hz ROOFING filter, except in LOSS (which will be "compensated for" later). Pesonally, for cw work, I think both of those will be "too narrow" for my liking, especially if I want to "tune around the band" and not have signals suddenly POP into the final passband (which I like to keep fairly wide). I want to hear what's coming! de Doug KR2Q I had 2 CW filters in my TenTec OmniV and did a lot of A/B comparing with them. One was an 8 pole Inrad 400 Hz filter and the other was a 6 pole TenTec 500 Hz filter. I had them both in the rig at the same time specifically to decide which one to keep. I was able to detect the steeper skirts of the 8 pole filter as well as the narrower passband, but the factor that eventually tipped the scales was ultimate rejection. The TT filter, had better ultimate rejection. Once I tuned past a signal, it went away and didn't come back. With the Inrad filter, the signal would drop quicker, hit bottom and then come back up. I could hear strong signals 6-8 KHz away. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
Oh, and no I don't think I did an apples to oranges comparison. The
filters, whether placed early or late in the signal chain, have the same effect on bandwidth and out-of-band signal rejection. What I compared was 8 vs. 6 pole and that showed me some things that are applicable to the 5 vs. 8 pole choice we have with the K3. While the filters were not in the same place as they would be in a "roofing" application, the info gathered was certainly applicable. - Keith N1AS - - K2 5411.ssb.100 - -----Original Message----- The notation below (previously posted) is referring to the final passband filter and NOT a roofing filter. You are trying to compare apples and oranges. =============================== I had 2 CW filters in my TenTec OmniV and did a lot of A/B comparing with them. One was an 8 pole Inrad 400 Hz filter and the other was a 6 pole TenTec 500 Hz filter. _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
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