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RAT5 Information Manual 1.2.0

August 2010

This manual is the complete reference document for RAT5, containing all aspects of

construction and operation.

This manual refers to RAT5 hardware version 1.2

Please check you are reading the latest version of this document by checking

www.s9plus.com for any updates.

Please read this document fully before commencing construction

There are bound to be errors – please report any you find !

www.s9plus.com

Summary of Contents for RAT5

Page 1: ...nstruction and operation This manual refers to RAT5 hardware version 1 2 Please check you are reading the latest version of this document by checking www s9plus com for any updates Please read this do...

Page 2: ...Single Conversion AM Receiver Kit for 160m or 80m RAT5 kit of parts Easy to Build This kit is suitable for constructors with little or no previous experience of kit building A basic level of solderin...

Page 3: ...on 10 4 Testing and Alignment 13 4 1 Power off Tests 4 2 Power on Tests 4 3 Local Oscillator alignment 4 4 IF and RF Alignment 4 4 1 IF Alignment 5 Interfacing 18 5 1 Connection Method 5 2 Connections...

Page 4: ...ith the FAT5 transmitter project Maybe the complete RX TX could be the FAT RAT project Is there a kit Yes Based around a 3 x2 drilled and tinned single sided fibre glass PCB the kit contains all the c...

Page 5: ...detailed below Changes to the PCB The PCB to which this manual refers is version 1 2 The previous PCB was version 1 1 New IF filter PCB Version 1 2 incorporates a different 455kHz filter We have now m...

Page 6: ...sumer equipment In amateur use a squelch feature is useful and this has been designed into the circuit Low power consumption RAT5 consumes typically less than 50mA from a 9V to 15V supply making it su...

Page 7: ...et parts of the spectrum The image frequency for 3615kHz is 2705kHz and the image frequency for 1963kHz is 2873kHz Compare with say a low side LO on 160m which would produce an image frequency in the...

Page 8: ...use with a frequency display future add on project and to assist with setting up 2 2 3 IF Filter The IF tuned circuit L2 C4 is tuned to 455kHz giving a good match into the IF filter FL1 a 6 pole ladde...

Page 9: ...signal to inaudible levels When a carrier is received such that the AGC line at U2 pin 2 goes more positive than the level on pin 3 the comparator output will drop to zero cutting off Q1 and enabling...

Page 10: ...2 5 below shows an actual frequency response plot of a prototype unit The steepening LF roll off is caused by the increasing reactance of C27 which becomes significant at lower frequencies 2 3 3 Audio...

Page 11: ...hen check all holes are drilled The boards will have been carefully checked but as they are hand drilled there is always the chance a hole could be missed It s easier to correct any problems now rathe...

Page 12: ...referred Orient the capacitors such that the values are visible from the same side __ Solder Q1 VR1 and D1 taking care not to mix them up they look similar Follow the case orientation shown on the PCB...

Page 13: ...U1 16 U2 4 and U3 4 U2 3 and U3 3 will read to earth via RV2 and RV3 sliders respectively when the controls are fully CCW vary the controls to confirm Before inserting the ICs carefully check all sol...

Page 14: ...aid __ With no leads connected using a multi meter measure the resistance across the power input pins PL3 1 2 Connect the positive red meter lead to PL3 2 A typical reading is 24k ohms after allowing...

Page 15: ...counter is available use an oscilloscope Failing that assume the LO is running and search for the signal on a receiver Decide on a receive centre frequency to use 3615 kHz for 80m or 1950 kHz for 160m...

Page 16: ...requency of 3615kHz with VC1 set to minimum the tuning range is typically 20kHz With VC1 set to maximum and L1 re adjusted for 3615kHz the tuning range is typically 150kHz 4 4 IF and RF Alignment IF R...

Page 17: ...te core from its preset position tuning for a maximum S meter reading The tuning will be quite broad but it should be possible to establish a centre position for the core It s a good idea to monitor t...

Page 18: ...sing the squelch Further signal generator based squelch tests Set the squelch so that it just mutes the receiver Apply a carrier of 3uV PD Check the squelch opens at this level Apply a 1V PD carrier C...

Page 19: ...Wires can also be soldered directly to the pins of PL3 but the recommended method is to use the companion socket strips Again wires can be soldered directly to the strips but the method preferred by...

Page 20: ...onsequence A 10k series variable resistor can be used to set the meter level as required 5 3 1 Calibration Calibration of the S meter can be attempted If a calibrated signal generator is not available...

Page 21: ...able trips then Maplin s Hybrid battery range is worth a look They self discharge much more slowly than other rechargeable types 5 7 Choice of enclosure and boxing the unit In the UK Maplin carry a st...

Page 22: ...U1 16 U2 4 and U3 4 U2 3 and U3 3 will read to earth via RV2 and RV3 sliders respectively when the controls are fully CCW vary the controls to confirm If all continuity checks read ok insert all Ics a...

Page 23: ...ow Violet Orange Red R13 22k Red Red Orange Gold R14 10k Brown Black Orange Brown R15 10R Brown Black Black Red R16 10k Brown Black Orange Brown R17 2k2 Red Red Red Gold C1 47p 80m 150p 160m 390p MW 4...

Page 24: ...p Cut to length as needed Non PCB item SK1 2 3 Header socket 10 way Cut to length as needed Parts List by value R C only with idents Value Component Marked as 10R R15 Brown Black Black Red 22R qty 2 R...

Page 25: ...RAT5 Manual version 1 2 0 RAT5 Information Manual version 1 2 0 GW4GTE 2010 Page 25 of 29 Appendix 2 Circuit Diagrams...

Page 26: ...RAT5 Manual version 1 2 0 RAT5 Information Manual version 1 2 0 GW4GTE 2010 Page 26 of 29...

Page 27: ...RAT5 Manual version 1 2 0 RAT5 Information Manual version 1 2 0 GW4GTE 2010 Page 27 of 29 Appendix 3 PCB Layout Version 1 2...

Page 28: ...squelch but a sustained level from a carrier will trigger the squelch after a few seconds The downside is that the start of an AM transmission is missed but of course during a QSO the squelch can be l...

Page 29: ...n 1 2 0 GW4GTE 2010 Page 29 of 29 Appendix 5 Builder s Gallery Excellent example built by Eric GW8LJJ for club demonstration in this build the controls are not directly soldered to the PCB The amazing...

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