Hi! I did my homework! Indeed, the carrier oscillator crystal frequency was not exactly set to 5.645 MHz, mainly due to C2 which was offest by 30 degree and a bit also to T14 which was not completely peaked. Switching sideband switch back and forth it was easy to note difference in plate current and I adjusted C-2 to make the current and output of the sidebands equal. Plate current is now about 0.08A (similar to the bias value) and output zero or close to zero.
Plugging the mike, both sidebands now sound much more the same. I see about up to 50 watts (average power) on SSB whatever sideband. Listening my modulation with a receiver my modulation seems ok ! However I had still to rebalance the carrier balance control which was set fully counter clockwise. Setting the function switch to CW and and PTT on mic ON the relative output meter stays at zero for whatever adjustment of the carrier balance control !!!! So, I CAN'T rebalance the Carrier Balance control !!!! Why is that??? 73, Frank IZ2OOS 2010/3/22 iz oos <izo...@gmail.com>: > Hi! > > I did my homework! Indeed, the carrier oscillator crystal frequency > was not exactly set to 5.645 MHz, mainly due to C2 which was offest by > 30 degree and a bit also to T14 which was not completely peaked. > Switching sideband switch back and forth it was easy to note > difference in plate current and Adjust C-2 to make the current and > output of the sidebands equal. Current was about 0.8 and output zero > or close to zero. > > > Plugging the mike, both sidebands now sound much more the same, > however I had still to rebalance the carrier balance control which was > set fully counter clockwise. Setting the function switch to CW and and > PTT on mic ON the relative output meter stays at zero for whatever > adjustment of the carrier balance control !!!! So, I CAN'T rebalance > the Carrier Balance control !!!! > > Why is that??? > > 73, > > Frank IZ2OOS > > > > > 2010/3/21 Garey Barrell <k4...@mindspring.com>: >> Frank - >> >> Start with the Carrier Oscillator, Filter Match & Balanced Modulator >> alignment in Section VII, Section B. The idea is to get the Carrier >> Oscillator "centered" in the valley between the two filters as shown at "0" >> on Page 37. >> >> 73, Garey - K4OAH >> Glen Allen, VA >> >> Drake 2-B, 4-B, C-Line& TR-4/C Service Supplement CDs >> <www.k4oah.com> >> >> >> iz oos wrote: >>> >>> Hi Folks, >>> >>> I am testing my T-4XB. Before going in the air, I wanted to check my >>> modulation first. Using different high impedance microphones I >>> transmitted into a dummy load and listened to the receiver without >>> antenna. I found that the LSB has a different modulation compared to >>> the USB. The USB is warmer and stronger. The LSB seems to me with many >>> highs and without basses. The USB is very clear and according to my >>> average output meter has more average power than the LSB mode. >>> Listening with the wrong sideband, in LSB when the transmitter was in >>> USB, I could still copy my modulation. Instead, listening to USB with >>> the transmitter is LSB, I could hear nothing at all. >>> >>> Do you have any idea where I could have a look? >>> >>> 73, >>> >>> Frank IZ2OOS >>> >>> >> >> _______________________________________________ >> 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
