ARDFrx2 Partslist, construction tips.
pa0nhc 201040509 (s34-p45)
NL=>EN : 20140721

This design was made with in my mind: use readily available cheap components, if possible from one supplier.
www.conrad.com supplies nearly all components.
All resistors : 2.5x6.5mm 0.25W metalfilm, wires bend to RM7.5 
Most capacitors : RM5 or RM2.5.
Keep the wire legs of ceramcic capacitors AS SHORT AS POSSIBLE for a high SRF.
NP0 caps are from Murata.
Elco's: Attention to dimensions stated.

On a home made PCB:
>>> Solder "ground"-connections on BOTH PLANES (where possible). <<<


C1 82p NP0 451372
C2 10p NP0 457124
C3,30,31 150p 451419
C4,5 22p NP0 531975
C6 330p NP0 451499
C7 3p3 NP0 (sets tuning range to approx. 850kHz) 451216
C8,41,47 100n 531855
C9,10,35 1uF ceramic RM5 (or elco 5mm dia.) 453382
22n cer. 531808
C12,40 100uF, max d=6.3 - RM2.5 443906
C14 1000uF 6.3V. max d=8 - RM3.5 422024
C25,26,28 33p NP0  451313
C32 4n7 FILM (!ceramic is microphonic!) 455059
C33 3.3uF RM2.5 tantalium 481696
C34,35 22n 459974
C36,37 220p 451466
C38 2u2. d=5, RM2   (elco or tantalium) 447029
C39 150n ceramic RM5 (for R20=470). If the value of R20 is changed, adapt C39 for -3dB @ 3kHz .
Example: R20=1k, C39=>82n.



R1 1k  
R3 22k MUST BE METALFILM (oscillator phase noise !)  
R4,12 10k  
R5,21 47k lin (foil) 457748
R6 220k  
R7 2k2  
R8,9,11,13,14 470k  
R15,18 33k  
R16,17 330k  
R19,26 4k7  
R20 470 (adapt to the sensitivity of the used HPH)  
R22 100k  
R24 6k8 (Sets min. gain)  
R25 12k (sets max. gain)  
Rx 1k5 (adapt to cristal filter. Rx=[ZinFilter-1k5] )  
Ry 3k0 (3k3 // 33k)
(adapt to cristal filter. Ry=ZoutFilter )



IC1 NE/SA 612N / 602N 152285
IC2 TL072 155617
VR1 LP2905CV 5V 104276
D1,2 1N4148  
D3 zenerdiode 4.7V  
D4 1N4002  
FET1,2,4 BF998 153029
FET5 BF244b (dgs) low IDss
(Ids=200uA @ Vgs=1.6-3.8V)
CD1 BB535 (or BB149 or eq.)
(Cd= 18 to 9.5pF @ Vd= 1V to 5V)


For max. stability, affix the windings of L1,2,3,4,6 to the coil form with glue
(Pattex MULTI or nail lacker). Let dry.

    L1, L2:
Coilform FM5.2, Conrad 516635
L1= 4t 0.15mm ca. 120nH.
L2= 3t  0.15mm ca.  70nH

Coilform FM1.0, Conrad 516341
Pri 25t, sec 25t, 0.15mm, ca. 5.7 uH.
REM: start of winding at pin 5 and pin 1. 
!!Wind both windings in the same direction!!
Before installing: FIRST pre-tune the
sec. to 10.7MHz, with a 39p test
capacitor connected to pins 1-5,
with the coil in the can.
This makes setup easier.

Neosid SD75 22uH RM5 (SRF >= 11MHz)
Conrad orderNr 535389

SD75 68uH RM5 (SRF ca. 10MHz)
Conrad orderNr 535400.

    FB1 - 9:
One-hole ferrite pearl ca. 4x4mm.
NB: affix the bead to the wire or PCB with glue
to prevent shaking (or instable oscillator).

Cristal filter 10M12B
Rx = Xfilter-1k5  (1k5)
Ry = Zfilter         (3k3 // 33k)

or use some 10M16B or 10M20B.