[Drakelist] R-4C Noise Blankers, Dynamic Range roofing filter mod's
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
Re: [Drakelist] R-4C Noise Blankers, Dynamic Range roofing filter mod's
I have added external DSP units to help noise. One particular rig I have with dual receivers I have one on each channel. It has made the difference between Q or no Q. Just a suggestion from here. 73, Mike WA5POK -- From: Don Jones k...@comcast.net Sent: Wednesday, February 02, 2011 12:01 PM To: drakelist@zerobeat.net Subject: [Drakelist] R-4C Noise Blankers,Dynamic Range roofing filter mod's 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 ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] R-4C Noise Blankers, Dynamic Range roofing filter mod's
On Wed, 2 Feb 2011 10:01:33 -0800, Don Jones wrote: Basically all you get is the receiver performance from a FT101B/E, the only advantage R-4C has is the passband (IF Shift) tuning. Yaesus give me headaches, Drakes do not. That's my main performace criterion. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime. HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] R-4C Noise Blankers, Dynamic Range roofing filter mod's
The truth be known, IMHO, If I just had the Sherwood R-4C, T-4XC, L-4B and MN2700...and sold everything else..I could get by quite nicely! OMG...I would be back in 1974 I have a Collins S line and KWM2, 30-L1 A Hallicrafters SX-115/Ht32B A Hallicrafters SX-117/HT44 and a TT Orion II and Alpha 91b I do enjoy them all at times. Considering everything...may favorites are the C line and Orion II. The C line will do all most ever need..but the OII is nice for a lot of reasons too. How many radios can you operate at once anyways! Maybe time to sell some stuff. 73, Lee Lee Simmonds Summit DCS LLC 260-799-4077 Office 260-403-6936 Cell -Original Message- From: Jim Shorney jshor...@inebraska.com To: drakelist drakelist@zerobeat.net Sent: Wed, Feb 2, 2011 8:32 pm Subject: Re: [Drakelist] R-4C Noise Blankers, Dynamic Range roofing filter mod's On Wed, 2 Feb 2011 10:01:33 -0800, Don Jones wrote: Basically all you get is the receiver performance from a FT101B/E, the only advantage R-4C has is the passband (IF Shift) tuning. Yaesus give me headaches, Drakes do not. That's my main performace criterion. 73 -Jim -- Ham Radio NU0C Lincoln, Nebraska, U.S.S.A. TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! Give a man a URL, and he will learn for an hour; teach him to Google, and he will learn for a lifetime. HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
