SAILOR / DEBEG 7284 (R-110) SSB RECEIVER modifikation

bringing the radio back to live without the TX

when you operate the radio without the transmitter the receiver is quiet. a jumper is needed at the power connector on the back of the RX to enable audio. the operating voltage can be changed from 24 V to 12 V inside the radio if needed.

i dont remember what the wite wire was good for, sorry ( marked with " ? " )

80m fix channel modification

the fix channel converter units have a X-tals for each channel. the local oscilator operates 600 KHz below the receiving frequency. for maitime voice trafic on shortwave USB is used. my RX came with a lot cannels in the 2 MHz range, so i could change the converting dirction to reach the 80m band. example: 2550 KHz + 2 x 600 KHz = 3750 KHz changing the converation orinetation also changes the sideband dirction, so i can receive 80m in LSB on the image frequency now ! tuning the converter channel is easy, there is a screw in the X-tal box for the bandfilters. first turn the screw full counter clockwise, than turn it back til maximum noise is heared ( with antenne connectet). the tuning is sharp, the only mistake you can do is, tuning to the original RX frequency. X-tal frequency fine tuning can be done with the trimmer C .

LSB / USB modification

SSB detector and BFO: the 600 KHz BFO signal is provided by mixing a 6.7 and a 7.3 MHz X-tal controled oscilators ( T601, T602). the mixer is bulid with T603 and T604. the product detector is T605. the clarifier can shift the 7.3 MHz oscilator. the 6.7 MHz oscilators capacity diode D601 has a fixed voltage, this can be changed easy. before modification: the cristal filter in the RX is LSB, so dont get confused here. turn the clarifier to 12 o´clock. check BFO frequency at C619, it should show up 600 +/- KHz. this is the USB BFO frequency. than turn down the frequency of both oscilators 700 to 800 Hz (C602 and C603). the result shall be abuot 1.5 KHz BFO frequency shift.

modification: desolder R601 (10K) on the +6V side and conntct a wire to the new LSB/USB switch. connect the 2 trimpots to the switch as shown in the diagram. get 18 Volts from the circuit bord and feed the trimpots. alignment: put the new USB/LSB switch in USB position and turn the USB-trimpot back to the original BFO frequency. than switch to LSB and turn the LSB trimpot until you can clearly copy LSB transmisions. fine tuning can be done with the LSB and USB trimpots

the modification can also be done without checking the original BFO frequency, as i did. but you need a USB/LSB transmitter or a partner who provides a test signal. please give me feedback if you have problems, i still dont found my notes about this mod. the shematic diagramm is online. search for "Sailor R-110.PDF".