GAREY - K4OAH <[EMAIL PROTECTED]> made an utterance to the drakelist gang ---------------------------------------------------------------------- David -
The only one of the group that lends itself to "widening" is the R-4C. There is a 4 pole 8 kHz "roofing" filter up front in all the R-4 receivers that limits the "ultimate" IF bandwidth. The L-C Passband tuners could possibly be modified, but certainly NOT a simple mod. The R-4C though, has a separate AM filter socket under the chassis, and 8 pole crystal filters were offered in both 4 and 6 kHz bandwidths. The receiver came from the factor with a 150 ohm, 2W resistor installed between the input and output pins of the AM filter socket, effectively giving an 8 kHz IF bandwidth set by the roofing filter. The 2-B uses essentially the same Passband tuner as the 4 line, again not a candidate for easy modification. All these receivers were designed as CW/SSB receivers, with AM included solely for "backward compatibility". AM was considered to be "on the way out" by most hams (and others) in the 60's when these receivers were designed. A nice NC-183D, HRO-60 or NC-300 would be a much better sounding AM receiver! 73, Garey - K4OAH Atlanta Drake C-Line Service Manual <http://hr99.home.mindspring.com/R-4C_Servicez/> David Toepfer wrote: > David Toepfer <[EMAIL PROTECTED]> made an utterance to the drakelist gang > ---------------------------------------------------------------------- > R-4 questions: > > The Drake R-4(a/b/c) seems universally regarded as a file receiver. It seems > bets regarded by CW and SSB users, and less so by AM users. At 4.8kHz max IF > bandwidth it is usable for AM, but does not seem to lend itself to current > practices of AM users. > > Does anyone have any experience at opening up the R-4(a/b/c) IF to > 6/7/8/10/12kHz more in keeping with current practices? > > Would the R-4B tend to lend itself better to such a modification because of > what I believe is it's LC IF filters as opposed to the crystal filters used in > the R-4C? > > ---- > > 2-B questions: > > The Drake 2-B seems even less well regarded by AM users. At 3.6kHz max IF > bandwidth its use beyond simple communication via AM seems limited. > > Similarly, does anyone have any experience at opening up the 2-B IF to > 4.8/6/7/8/10/12kHz more in keeping with current practices? > > Similarly, would the 2-B tend to lend itself better to such a modification > because of what I believe is it's LC IF filters? > > ---- > > R-4/2-B questions: > > Or, is it perhaps a simple matter of limits imposed or at least evident > earlier > in the IF chain preclude aspirations of such receiver modifications? > > dt > ---------------------------------------------------------------------- On Behalf of GAREY - K4OAH <[EMAIL PROTECTED]> Submissions: drakelist@www.zerobeat.net Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ ----------------------------------------------------------------------
