QRPproject DL-QRP-AG, Manual

Page: 22 / 53

Version: 13. Sepe
,m
er 2004
22
Section 7 IF amplifier, IF filter
Begin with the crystals. These are not the lowest parts, but in prototyping,
we found the ground connection of the crystals difficult, when the other
parts were in place. Please again note the minimum distance between the
crystals and the pc board (use cut off resistor leads to help!).
[ ] Q2 8,000MHz HC18 C4/5
[ ] Q3 8,000MHz HC18 B4/5
[ ] Q4 8,000MHz HC18 B4/5
[ ] Q5 8,000MHz HC18 A4/5
In close proximity to the crystals, you will find
ground soldering spots (Q5 left lower, Q4 and Q3
lower, Q2 right lower). Solder cut off resistor
leads into these spots, an solder the free ends
to the crystal bodies at half height of the narrow
side of the respective bodies. Grind the crystals
lightly with sanding paper, this eases the solde-
ring.
[ ] Crystal ground connections, 4 pcs.
The following 5 diodes are in TO92 casings. They look like
transistor, but only have to leads. Mount according to the
placement diagram.
[ ] D15 BB112 C4
[ ] D16 BB112 B4
[ ] D17 BB112 B4
[ ] D18 BB112 A/B4
[ ] D19 BB112 A4
BEWARE, the BA479 should not be confused with the 1N4148.
Use a magnifier
!
[ ] D13 BA479 C/D
[ ] D14 BA479 C/D3
[ ] D20 1N4148 B5
[ ] D21 1N4148 C5
[ ] D22 BA479 A4
[ ] T12 BF246A C4
[ ] T13 BF246A C4
[ ] T14 BF199 A3
[ ] T15 BC546B A3
[ ] R56 1,5K D3
The following resistor is in principle an adjustment value. The Intermodula-
tion characteristics of the receiver can be optimized, if this resistor is
chosen so that the quiescent current through it is about 10 mA.
[ ] R57 220R will be installed later on
[ ] R58 330R C4
[ ] R59 47K C4/5
[ ] R60 47K B4/5
[ ] R61 47K B4/5
[ ] R62 47K A/B 4/5
[ ] R63 47K A4/5
[ ] R64 330R A4
[ ] R65 47K A3
[ ] R66 82R A3
[ ] R67 820R A3
[ ] R68 12K A/B3
[ ] R69 33K A/B3
[ ] R102 68K B5
[ ] C59 47nF 473 D3/4
[ ] C81 47nF 473 D3/4
[ ] C82 22nF 223 C4
[ ] C83 22nF 223 D4
[ ] C84 22nF 223 C5
[ ] C90 10nF 103 C4/5
[ ] C91 10nF 103 A5
[ ] C92 22nF 223 A4/5