I agree, when using the 8kHz Drake Roofing filter the 4NB noise blanker will clean-up some interfering noise sources. But only some of the time. I (and many others who have e-mail me privately) have found that you get better noise reduction by reducing the IF BW's. This would include going to a 600Hz roofing filter making the 4NB ineffective - but more importantly - NOT NEEDED.
I look at a "hot-rod Sherwood R-4C receiver" as a utilitarian tool used to dig deep down into the noise floor and root out S Unit 0 weak signal DX stations buried in the midst of QRM. I did not completely buy into the "wild claims" of the users of these Sherwood R-4C's until I actually used one. All I can say is, "Holy Cow!" I am now a "convert" of the writings W8JI regarding the R-4C in its un-modified state. This "Holy Cow" is based upon side by side comparisons to a stock Drake R-4C to a Sherwood R-4C. Basically all you get is the receiver performance from a FT101B/E, the only advantage R-4C has is the passband (IF Shift) tuning. Conversely if one is rag chewing on SSB with 3kHz wide "Hi-Fi SSB" (or worse yet AM), they generally are not concerned about digging out weak CW signals that are S-0 on the S meter. These users typically are happy campers with a 75M 20+dB over S-9 QSO while running 1.5kW (or more) for a "in-state rag chew." They remain happy campers until someone moves in 2kHz away and is running similar power. But at least their 4NB noise blanker's work... BTW, the measured 2kHz Spacing Dynamic Range of a TR-4C is 68dB which is 10dB better than the stock R-4C. Plus the 180W output of the TR-4C will drive a GG 4-1000A amplifier with 3500Vdc B+ to 2,300W-rms out on 75M SSB. 73 es Gud DX, Don Jones KO7i Arlington, WA _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
