QRP PROJECT Blue Cool Radio, Manual

Page: 13 / 45

Rev:Nobember 20. 2006
13
Place the prepared blue plastic with its ferrite
cap on the the coil. Place the shield can over
the plasitk, The two noses of the shield should
go through their corresponding holes in the
PCB, but do not solder the shield now.
[ ] L4 Neosid 7.1 F10b B-5
Reson. Winding: 18 turns 0,1 mm laquered wire
Coupl. winding: 2 turns 0,1mm laquered wire
Now finish group 4:
[ ] C35 47nF (473) A-4
[ ] C30 82pF (82p or820) A-4
[ ] R24 10K upright A-4
[ ] R22 1K upright A-4
[ ] C31 47nF spaceing 5mm (473) A-4
[ ] C33 47nF (473) A-4
[ ] C28 10pF (10p or100) A/B-4
[ ] R21 150R upright A-4
[ ] R20 100K upright A-4/5
[ ] R19 5,6K upright A-5
[ ] DR10 47uH SMD bottom A-5
[ ] C23 47nF (473) A-5
[ ] C24 150pF (151)
A/B-5
[ ] C29 2,5-60pF Foil variabke cap
7,5mm black A-5
[X] R18 not used
A/B-5
[ ] C32 10 u F 35V rad.
A/B-4
[ ] C34 100 u F 16V rad.
A/B-4
The Dual Gate MOS T7, BF981 is very
sensitve against ESD remember the ESD rules. The picture left shows the
pinning as you you see it from the upper side, orinting readable. It will be
installed exactly as you see it here. The little Dot in the drawing remarks the
long drain pin. Bent all 4 pins carefulle downwards 90 degrees, and place
the transistor into it´s holes. If all is ok, you still can see the type-print,
otherwise you have bent the pins the wrong direction. Solder all 4 pins from
the solder side (bottom of PCB)
[ ] T7 BF981 Attention, ESD rules!!!
A-4
The Quartz must be soldered a little above the PCB to prevent it against
getting shortened by solder at its bottom. Easiest way to to is to use a cut
of from a resistor temporary between the PCB and the quartz. Dont forget
the to remove the cutof after soldering the quartz
.
[ ] Q4 4,915MHz HC49U
A-4/5
Next to the Quarz you will see a little rectangular soldered pad. This is to
ground the housing of the quartz. Solder a resistor cutoff to this pad and
solder the other end to the quartz housing at about half the height of the
housing. Soldering at the quartz housing is easier, if you clean the solder
place with a glass hair brush or similar tool.
[ X] C18 47nF SMD0805 bottom C-5
[ X] C21 47nF SMD 0805 bottom B-5
Last thing in this section is coil L5.
Wind 18 turns between pin 1 and 2 as you learned it for L4. The coupling
this time has 6 turns instead of 2. Wind 6 turns between Pin 3 and 4
[ ] L5 Neosid 7.1 F10b A/B-5
Resonate winding: 18 turns 0,1 mm laquered wire
Coupling winding: 6 turns 0,1mm laquered wires
Thats all. The IF Amplifier is ready built and rady to be
tested. Before testing, again check your work with the
help of a magnifier and a bright lamp. All ok?
Connect a Headphone. Connect a piece of wire to point
X as shown in the drawing below. Dont solder, just plug
it into the hole. The other end lay without electrically
contact on the DDS Modul. This will grab some RF from
the DDS output to the IF amplifier. The upper end of the