Building Ronja Inferno Receiver

Overview

We are going to build a tin box with lid here. Box will be equipped with mounting brackets and wire leads. Finally we'll solder receiver electronics inside. The result without the lid will look like this except for mounting brackets:

Postscript / PDF / EPS / BIG png / DXF (qcad)

Box Template

Print this template on a calibrated printer. You can also use RX and airwire TX template together.

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Bracket Template

If you plan to build optical head and the pipe has diameter less than 105mm, skip this box and the next one.

Subtract box width (normally 92mm) from the optical head's pipe inner diameter. If you don't plan to build optical head, assume 145mm. Select the template according to the resulting number from the Side template list and print it. The template is for two boxes, you need just half of it.

Make the brackets

Drill the side template out and bend it. Wash the template off in warm water.
Solder the M4 nuts over the holes from the inside.

Postscript / PDF / EPS / BIG png / DXF (qcad)

Main box

Note the picture shows an older type of the box.

Glue the box template on tinned steel plate.
Cut and drill out.
Bump the indicated points.
Bend into a box shape.
Remove the template with warm water
Solder the corners up
Solder the partitions (strips with square notches) inside the box. The strip positions are given by the bumps on the bottom. Solder all along their gap, not just in several points.

Solder on brackets/nuts

If you have brackets, then solder the brackets to the case, otherwise solder bare M4 nuts from the outer side over the 4mm holes.

Detector

Put the SFH203F detector into the 5mm hole in the case and solder anode to the box. The Anode (A, the longer pin) is described in the lower left corner of the schematic (below). When inserting the detector into the hole, make sure the detector is perpendicular to the plane (is not askew) and about 1/3 of the plastic body is protruding out. The chip must be inside otherwise catches intereference!

After soldering, fix it from the inner side using the thermal glue gun (optional, recommended).

Grommet

Put the cable grommets into the 8mm holes. Note: the box in the picture should have mounting brackets soldered on.

Cutting cables

Cut the following types and lengths of cables:

Qty	Type	Length
3	shielded single-conductor	20cm

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Stripping

Strip 29mm of the outer insulation from the shielded cable on both sides. Strip 4mm of the inner insulation from the shielded cable on both sides.

Cover all bare ends with solder.

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Installing cable leads

Put the bare ends through the grommets as seen in the picture. Leave the middle cable's shield unconnected but solder the remaining shields to the box. Seal the cables inside the grommets with sillicone sealant (you can also use thermal glue, it is faster). Seal from both inside and outside of the grommets. When sealing the outside take care not to occupy the place where the lid will be (the rim of the box).

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Copper stubs

The cables ends that are not inserted into the box need copper stubs. Solder 6 stubs made from 4mm^2 uninsulated solid copper wire.

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Colour insulation

Insulate the stubs with colour duct tapes according to the diagram.

Making the coil

Take the 8.5mm bit bit and wind a 10-turn coil on it from the insulated1mm^2 hard copper wire.

Placement of selected components inside the receiver

Key components

Place some important components into the box according to the drawing. Fix them by soldering on their ground lead. If they don't have any ground lead and you mind them rolling all around inside the box, you can glue them down using thermal glue gun.

We are going to place components according to a schematic. There are arrows in the schematic labeled "P*" where "*" varies. They don't mean any component, they are just test points.

Stereo picture

You can view a stereo picture of populated RX to get a notion how the components are mounted inside prior to starting soldering them down. Please note there should be mounting brackets instead of the screws:

Now the following components are already installed in the box:

U101
PD101
R105

R112
C174
Q101

Q102
Q103
J101
J102

J103
J104
J105
J106

		PostScript	PostScript + Gzip	PDF
Color	Dark	inferno_receiver_01.ps	inferno_receiver_01.ps.gz	inferno_receiver_01.pdf
	Light	inferno_receiver_00.ps	inferno_receiver_00.ps.gz	inferno_receiver_00.pdf
	Small	inferno_receiver_02.ps	inferno_receiver_02.ps.gz	inferno_receiver_02.pdf
B/W	Dark	inferno_receiver_11.ps	inferno_receiver_11.ps.gz	inferno_receiver_11.pdf
	Light	inferno_receiver_10.ps	inferno_receiver_10.ps.gz	inferno_receiver_10.pdf
	Small	inferno_receiver_12.ps	inferno_receiver_12.ps.gz	inferno_receiver_12.pdf

inferno_receiver.sch (gschem)

Component lists

Seznamy součástek

Schematic

Place the remaining components according to the schematic in this sequence:

C168 close to J101
C165 close to J101
C178 close to J103
C179 close to J103
C163 close to U101
C164 close to U101
C154 close to Q101
C153 close to Q101
L102
R101
C173
C167
D101
R103
C152
C161
C155
C151
C177
C175
L101
R122
C172
D103
C162
C157
D102

R102
R104
C156
R111
R113
R108
R109
R110
R115
C158
C166
R117
R120
R119
R107
C169
R116
R121
C178
R114
R118
C160
C170
C159
C171

Correctness check

Take the schematic and a multimeter and check everything except R106 (still missing). Check that the topology is OK (i. e. the wires lead where they should lead). Measure every resistor with a multimeter (sometimes it will show less if there is a current path around). Check every capacitor visually where the value is visible. Check every diode and transistor junction with diode measuring function of the multimeter. Scrawl out every part and wire you check on the schematic with a pencil. Check visually all soldered joints for quality and resolder all joints where suspicion may arise.

R106

Connect 12V regulated supply: + to J101 (red) and - to J102 (black). Set multimeter to 200mA and put red probe to P104A and black probe to P104. Measure current.

Disconnect from power. Select R106 according to this table:

Current [mA]	R106 [Ohm]
3-3.6	1.8k
3.6-4.4	1.5k
4.4-5.5	1.2k
5.5-6.5	1k
6.5-8	820
8-10	680
10-12	560
12-14	470
14-17	390
17-20	330
20-24	270
24-30	220
30-36	180

Solder the R106 into the receiver.

Schematic inside the lid

Print the small schematic (see above). Overwrite all part numbers that have been installed different than in schematic. Overwrite all resistor values that have been changed during tuning. Write down amplification factors of both 2N3904 transistors. Glue the paper on the inner side of the lid.

Postscript / PDF / EPS / BIG png / SVG (Inkscape)

Label

Print out the Ronja 10M Receiver label. Fill in the label and stick on the outer side of the lid.

Washers and nuts

Save the 4 M4 washers and 4 M4 nuts for future mounting.