My home-brew GPS antenna splitter

Ingredients:

• 1 aluminum square profile, appr. 2 cm x 2 cm, 1.5 mm thick
• 2 aluminum square sheets, appr. 2 cm x 2 cm, 1.5 mm thick
• 3 panel sockets BNC (change to the type you require)
• 1 carbon film resistor 220 Ohm 0.125 Watt
• 1 miniature ceramic capacitor 100 pF
• 1 soldering tag
• 12 self tapping screws 3 mm dia, 6 mm length
• 1 M3 metric screw 6 mm
• 2 M3 metric screws 25 mm
• 3 M3 nuts
• multicore solder

Recipe:

• Drill three holes 10 mm in three of the sides of the profile.
• Drill four holes 2 mm around any 10 mm hole - use a BNC socket as template.
• Drill a hole 3 mm in the blank side of the square profile
• Mount the BNC sockets to the square profile with the self tapping screws. Ideally, the ends of the connector tags are located within 2 mm from each other. If too close: remove some material off the tags using a file.
• Mount the soldering tag in the inside of the profile at the blind side using the 6 mm screw, and a nut
• Place the profile in front of you with the blind side facing you, call the left socket A, the top socket B and the right socket C.
• Solder the capacitor between tag A and tag B using a minimum of  lead length.
• Solder a wire bridge between tag B and tag C, again with minimal length.
• Make a 3 mm dia coil of 4 windings of one of the leads of the resistor.
• Solder one resistor lead to tag A.
• Solder the other lead to the solder tag
• Drill two holes 3 mm in the aquare sheets at the same locations.
• Close the profile with the square sheets and the 25 mm screws, and the nuts.
• Mark socket A: 'COLD RCVR' (the receiver which does not supply the antenna pre-amp), socket B: 'ANTENNA' and socket C: 'HOT RCVR' (the receiver which does deliver power to the antenna pre-amp).

What's important ?

• The leads between tag A and the capacitor, between tag B and the capacitor, and between tag B and tag C should be as short as possible to avoid losses by the selfinduction of the leads.
• Check with an Ohm meter:
  • no connection between the pin of socket A and the pin of socket B
  • zero resistance between the pin of socket B and the pin of socket C
  • 220 Ohm resistance between the pin of socket A and the profile
  • zero resistance between any socket housing and the profile.

Operation

• Connect one receiver to socket C and the pre-amplified antenna to socket B.
• Switch on the receiver and wait until it tracks a number of satellites. The signal strength should be identical to what it used to be without splitter, but with the same length of cable between antenna and receiver.
• Connect the other receiver to socket A and switch it on.
• The signal strength of the receiver connected to socket C should decrease by about 3 dB, the signal strength of receiver A should be identical to C.

Click here for an image of the splitter components.

Have much fun !!!