Hi Bent, The problem you're having is one of understanding how CW operation is achieved with the TR-4 family of radios. All of these radios have two crystal filters, which are selected using the sideband switch. In SSB and all receive operations, that carrier oscillator operates at (hopefully) the mid point between the two filter's passbands. Doing so adds 20-30 dB to the carrier supression in the transmitted signal. When X-CW is selected, and the radio is put into transmit, the crystal frequency is shifted into the "X" sideband filter, by several hundred cycles, so that there's a pure signal source, within the passband, and at an amount that provides a CW audio tone offset in the range that most CW operators are used to. When you have the sideband selector switch in the wrong position, the carrier oscillilator is being moved outside that filter's passband, and there's no where near enough excess gain in the RF amplifier and mixer stages to generate a transmit signal at a high enough power to drive the PA to any more than the idle current you notice. So you need to set the sideband selector to the "X" position to tune the radio. Because of the frequency mixing scheme, which actual sideband that is varies - as does which way the transmitted CW signal is shifted relative to the tuning dial. If the Lower Sideband light is lit, the on-air CW carrier will be lower in frequency than the dial indicates, and if the Upper Sideband light is lit, the on-air CW carrier will be higher in frequency than the dial indicates. Hope that helps, and 73 Bob, KD7NM
_____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bent Sent: Thursday, July 03, 2008 12:51 PM To: [email protected] Subject: [drakelist] TR-4C Help needed. Tune UP problem. Hello I need some help for my TR-4C which give me some trouble. Hopefully someone are able to give me some useful ideas. The receiver seems to be fully OK on all bands. But something is wrong on the transmitter side. I have added a table which show what happend if I try to tune UP on the different bands. When I turn the XMTR GAIN CW, and Mode Switch in X-CW, according to Instruction Manual for tune up, following happend: Band Lower sideband Upper sideband 80 Draw no current OK 40 OK Draw no current 20 Draw no current OK 15 OK Draw no current 10 OK Draw no current All the voltages from the AC-4 are OK. Bias current on all bands is OK. Why will the transmitter not draw current in the red marked areas. Thanks in advance. 73 Bent OZ5ZD
