ROX 2T PARTS LIST updated 31st August 2007 C 1 3-20p trimmer C 2 10n C 3 10n C 4 10n C 5 22p NPO C 6 22p NPO C 7 10n C 8 4p7 C 9 330p NPO / low K C10 2u2 C11 22n C12 100n C13 10uf 16v electrolytic C14 10n C15 4n7 C16 1n C17 100u 16v electrolytic C18 100u 16v electrolytic C19 47u non-polarized C20 10n C21 100n C22 100n C23 22u 16v electrolytic D 1 BB149 D 2 1N4148 D 3 1N4148 D 4 1N4148 F 1 Token LT10.7MFP F 2 Token LT10.7MFP IC1 SA602 (or 612) IC2 TA7613AP IC3 LE50EZ low dropout 5v regulator IFT (pink)10.7MHz L 1 T37-12 (100mm + 35mm SWG wire) L 2 TOKO 10mm or 7mm (3.5 turns with ferrite core for low side VFO) R 1 47kB log control pot R 2 0R R 3 4k7 R 4 220k R 5 0r R 6 680r R 7 4k7 R 8 3k3 R 9 33k R10 100k R11 47kA linear control pot R12 47r R13 22k R14 47k R15 100r R16 22K R17 10r R18 1k0 (see modification 1) RFC1 single bead choke RFC2 double bead choke SK1 headphone socket TR1 BS250 -------------------------------------------------- HARDWARE -------- 1 PP3 battery clip 1 2 pin header optional otherwise use link 2 25mm dia knob BOX --- 1 ABS BOX,112x62x31,RFI coated. 4 Retaining screws 1 Front panel sticker M3 BOLTS 4 M3 x 10mm SPACERS f/f 2 M3 x 8mm SPACERS m/f 2 M3 shakeproof washers 8 M3 BOLTS with captive sp washers M4 BOLTS 2 M4 x 25mm bolts countersunk head 2 M4 half height nuts 2 Single hole plastic pipe clips ANTENNA 2 element version. ------- 1 Director 960x25 steel tape 2no 5mm holes centre spaced 42mm 2 Driven element 500x25 3mm hole, 7.5mm from end, remove paint on inside curve and tin 1 Boom 300x21.5mm PVC overflow pipe 1 Saddle clips (for director) 1 Cradle piece 4" long cut from 20mm plastic conduit 1/3 cross section. 1 Yoke piece 4" long from oval conduit, fixing holes spaced 42mm 1 Yoke piece 4" long from oval conduit, fixing holes spaced 25mm 2 Locking piece 18mm long, from oval conduit, for locking driven elements 1 Velco hook 4" x 20mm, cut into 4 x 1" peices 1 Velco eye 4" x 20mm, cut into 4 x 1" peices 2 M4 x 12 bolt (director - tape to saddle) 1 M4 x 25 bolt (do) 2 M4 locking nuts (do) 1 M4 plain nut (director - saddle to boom) 1 M4 shakeproof washers 1 PCB NOTES Capacitors up to 500pf 2.5mm lead spacing 1n and above 5.0mm SUPPLIERS RS Components http://rswww.com Farnell http://www.farnell.co.uk Rapid Electronics http://www.rapidelectronics.co.uk CPC http://cpc.farnell.com/jsp/home/homepage.jsp Sycom http://www.sycomcomp.co.uk JAB http://www.jabdog.com Notes ----- R5/R6 suggested values. use 0R/330R for Murata filters type SFE10.7MVS or similar 0R/680R for Token LT10.7MFP with TA7613AP 330R/330R for Token LT10.7MFP if higher gain IF chips e.g.TDA1083 tend to overload. ---------------------------------------------------------- R anc C sorted by value C 1 3-20p C 8 4p7 C 5 22p C 6 22p C 9 330p C16 1n C15 4n7 C 2 10n C 3 10n C 4 10n C 7 10n C14 10n C20 10n C11 22n C12 100n C21 100n C22 100n C10 2u2 C13 10u C23 22u C19 47u (non polarized) C17 100u C18 100u R 2 0r R 5 0r R17 10r R12 47r R15 100r R 6 680r R18 1k0 R 8 3k3 R 3 4k7 R 7 4k7 R16 22k R13 22k R 9 33k R14 47k R10 100k R 4 220k R 1 47k log R11 47k lin ---------------------------------------------------------------------------- ASSEMBLY RESISTORS Most leads have to bent very tight to the body, for 0.3" pitch (not R8) R8 vertical R16/R17 (R17 shown as 'link' on pcb) - fit both to underside of board - leave leads projecting upward for connection for R1/SK1 DIODES PCB is supplied with D1/ BB149 fitted. CAPACITORS A few may need the leads re-bent to fit the hole pitch. C1 (trimmer) C19 - do not confuse with the place for the the 2 pin-header 2 PIN HEADER (next to C19) - intended for a soft/loud audio switch, but not found to be that useful, so suggest it is repaced with a wire link. SEMIs TR1 the profile is for a BS250P, check leadout if an alternative is used. INDUCTORS IFT1 - important - do not fill unused holes with solder on the pcb, the solder may short out to the 7mm can RFC1 - single bead - bend leads as the resitors. RFC2 - double bead - fit vertically as pre-bent. FILTERS & SCREEN ------------- Fit lead cut-offs to 3 holes on the screen pads between F1/F2, leads upright 15-20mm projection Lightly tack in the copper screen to the pad. (N.B. position so not to short the screen to R4) Turn the 3 leads over the top of the screen and trim. Add a few more solder tacks to the leads and pads to secure the screen. Fit F1 and F2 ( words on the filters face into the pcb) L1 --- One turn = one pass thru the center of the toroid. The main winding on L1 must be wound in the same sense for each half i.e. NOT mirrored Use a piece of 26swg wire 100mm long, folded in half. Tin the ends and centre fold. The easiest way to remove the enamell is to boil it off, holding the wire ends in a solder blob. Most modern 'Standard' enamels will boil, but you will have to be patient, unless you use the red - easy solder type. My method for winding. Use self locking surgical pliers to hold the wire at the fold point, then 3 turns each way 6 total. The antenna link winding is from a 35mm length of 26swg wire, 2 turns close wound. POT LEADS Fit lead cutoffs to the pcb for R11, projecting 15-20mm from top of pcb. FITTING THE POTS AND SK1 Assemble the pcb temporary into the box. Fit SK1 R1 & R11 on the box. Wire in the above. ------------------------------------------------------------------ Alignment procedure:- 1. Battery connected - check current - should be 18-22mA 2. Should hear white noise at full volume. 3. Touch R5 with a small screwsdriver - should hear SW broadcast signals - RX IC is working! 4. Attach a frequency counter to pin 7 of the SA602 with a 10x probe Adjust L2 to give approximate range 133-135 or 154-156 Mhz. 5. Use an AM signal source at 144.5Mhz, turn the tuning pot. to middle. Tune L2 until the signal is heard. Peak C1, peak IFT1 Notes L2 is about 80nH . I use a standard 10mm TOKO coil type MC120 E526HNA1000112 which has 3.5 turns. The exact type is not critical, the ferrite core will give a large adjustment range. MODIFICATIONS ------------- 1) Add a switch across pin 16 of IC2 with a 1k0 ohm resistor in series. This will greatly reduce the IF gain, and improve the operation when very close to the transmitter. Use a small latching or toggle switch, fixed between the two control pots.