I've found the same thing with respect to using the detuning resistor - it hasn't really made anything easier or more accurate for me. I suppose, when they were building and testing these sets that it shaved a few minutes off the technician's test time - which is significant for production testing but less so when you're the owner.
The other thing I learned long ago - after speaking with a Drake tech on the phone probably 25 years ago - was that the absolute height of the slugs is less important (as Garey mentioned) and there should almost NEVER be any reason to change the individual slug heights in the rack. If nobody has messed with them over the years, they should all be in the same positions they were in when the set left the factory. I find the easiest way to see if someone has been "fiddling" is to adjust the preselector so that all the front slug is level with the cardboard tube top. All the other slugs should also be level with their tube tops. If you see a discrepancy, look to see if it looks like the glyptol (the substance that keeps them from moving) has been disturbed. Other than that, just peak them and be done. 80 is quite sharp and 10 is quite broad, with everything else somewhere in between. 73, Steve, W1ES/4 -----Original Message----- >From: Garey Barrell <k4...@mindspring.com> >Sent: Feb 13, 2012 2:30 PM >To: Peter Ravn <fas...@privat.dk> >Cc: drakelist@zerobeat.net >Subject: Re: [Drakelist] R4B preselector alignment > >Peter - > >The setting of the Passband tuner is not significant when doing the >Preselector alignment. All >you're looking for is an amplitude peak. Sometimes the Calibrator signal is >too strong, especially >on the low bands, driving the AVC too far and making it difficult to see the >peak as you tune. >Alternate Calibrator signals vary in strength, so you can pick a lower one on >either side (+/- 25 >kHz). You can also put a smaller resistor on the ANT jack to reduce the >level. Use FAST AVC to >better see the peak. > >The resistive loads are to spoil the Q of either T3 and T4 while tuning the >other to minimize >interaction of the adjustments. I have found that it really isn't necessary, >that you can do just >as good an alignment by going through 3-4 iterations of the adjustments >without the loads, as the >interaction refines out. > >73, Garey - K4OAH >Glen Allen, VA > >Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line >and TR-4/C Service Supplement CDs ><www.k4oah.com> > > >Peter Ravn wrote: >> The otherwise comprehensive R4B preselector alignment instruction does not >> mention the position of >> the passband selector during alignment. Should it be in the same position as >> during passband tuner >> alignment, i.e. with the passband selector to .4, and the passband tuning >> knob to the shortest of >> the curved lines on the panel. Or does it matter at all? >> The manual suggests to use the S-meter when adjusting the preselector >> trimmers for maximum. I find >> it much better to use an VTM. Finally the idea of using alignment resistors >> on S5C and S5D escapes >> my understanding. >> Thanks >> OZ8CTH, Peter > >_______________________________________________ >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
