Ronja Twibright Labs

Building Ronja Signal Cabling2

Building Ronja Signal Cabling2


What we are going to build

We are going to:

  • Build one 1.5 meter long power exchange cable (W2-PWR)
  • Build one 0.6 meter long RSSI cable (W5-RSSI)
  • Equip the signal cables(s) (W1, W2, W5) with connectors (W4 and DE9).
  • Attach a W3-PROT lightning protection cable attached to W2-PWR.

Purpose of the cables

Power exchange cable (W2-PWR) allows both optical heads to share electrical power. The optical heads take electrical power from shields of the signal cable(s). Shield of RX signal cable (W1-RX) carries +12V and the shield of the other signal cable (W1-TX) carries 0V (Ground, GND).

Some connectors within Ronja 10M Tetrapolis/Inferno system are made of pieces of thick copper wire (W4), some are DE9.

W3-PROT lightning protection cable protects your home electric installation from a fire hazard if lightning strikes directly into the shield of signal cables (W1) laid on the roof. TV antenna and TV set are protected the same way.


Cut the following wires:
DesignationNumber of piecesLengthThickness (crosssection area in mm^2)Solid Wire/StrandedInsulatedShieldedNumber of (inner) conductors
W1-TX1Distance from PC to intended optical head mounting site AnyYesYes1
W1-RX1Distance from PC to intended optical head mounting site AnyYesYes1
W2-PWR11.5m AnyYesYes1
W4-STUB1229mm4Solid WireAnyNo1
W5-RSSI10.6m AnyYesYes1
Postscript / PDF / EPS / BIG png / SVG (Inkscape)


The W1 and W2 will be stripped asymmetrically. Let's call the ends short and long end.

Strip all the wires:

Wire insulation IDLength
(W1 long end, W2 long end, W5) outer insulation29mm
(W1 long end, W2 long end, W5) inner insulation4mm
(W1 short end, W2 short end) outer insulation10mm
(W1 short end, W2 short end) inner insulation3mm
W4Remove all insulation
When stripping the outer insulation, take care not to cut the thin wires of the shields.

Strip 10mm off W2-PWR outer insulation in the middle, so that the shield becomes accessible.

Covering with solder

Twist all visible stranded copper up. Cover the ends of the conductors with solder:

Wire IDLength of solder coverage
W1, W2, W54mm
W44mm in the middle of the stub
Cover the stripped place in the middle of W2-PWR with solder too. Solder up one end of W3-PROT to this place.
Gallery[1c3d] Gallery[1178] Gallery[1173]
  PostScriptPostScript + Gzip PDF
Color Dark cabling2_01.pdf
Light cabling2_00.pdf
Small cabling2_02.pdf
B/W Dark cabling2_11.pdf
Light cabling2_10.pdf
Small cabling2_12.pdf
cabling2.sch (gschem)

Soldering the DE9 connectors

Solder one or two DE9 connectors on the W1- cables, depending on whether two cables fit into one enclosure or not. Use the thin (0.7mm^2) hard copper wire to interconnect the pins and the shell. Make sure the connection to the shell will not prevent cover installation.

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


Solder eyelet on the single end of W3-PROT. Solder stubs (W4) on all free ends of W1, W2, and W5 according to the drawing.
Gallery[115b] Gallery[117a] Gallery[13ff] Gallery[13b7]
Conductor designatorColourFunction
W1-RX shieldRed+12V
W1-RX innerBlueSignal
W1-TX shieldBlack0V (GND)
W1-TX innerBlueSignal
W2-PWR shieldBlack0V (GND)
W2-PWR innerRed+12V
W3-PROTBlackEarth protection
W5-RSSI shieldBlack0V (GND)
W5-RSSI innerBlueRSSI voltage


Wrap up (insulate) the soldered joints with coloured duct tape according to the table. Use enough tape to reinforce the ends of the cable mechanically too (to prevent it from breaking off during repeated bending).
Gallery[1162] Gallery[1400] Gallery[13b8]
Gallery[1c3e] Gallery[117b] Gallery[1176]
An expected information missing here?