4 Way GPS Antenna Splitter
with DC Amplifier

This is a 4 way GPS splitter that includes amplification to make up for the 4-way divider loss.
The parts breakdown is:

• Satellite TV 13 dB gain Amplifier RS 16-1156 -
• 4-Way Satellite TV Splitter RS 16-2579
• F(m) to BNC(f) Adapter RS 278-256
• Short BNC(m) to BNC(m) cable RS 278-103 & 278-1314
• 75 Ohn F(m) Termination RS 15-1144
• F(m) to F(m) barrel RS 278-275 or 278-219

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
I moved the line amp outside about in the center of the coax feed to make up for coax loss.  Of course the actual GPS antenna, a Motorola hockey puck, has a built in amplifier.

19 April 2003 - By connecting the antenna from a Garmin GPS III Plus to one of the output ports and taping it to the antenna on a military PLGR GPS receiver the receiver works extremely well, locking onto signals that the Garmin can not capture with a direct antenna connection.

23 Aug 2003 - Added a Trimpack AN/PSN-10 GPS receiver to the system.  This required inserting two more of the DBS satellite amplifiers between one of the 4-way divider outputs and the trimpack.

5 Sep. 2003 - While experimenting with various amplifiers, I checked with an Ohm meter and the port I was using showed DC open.  Then applied 18 Volts to get full gain from the Radio Shack (RCA D903) amplifier and notices that it was drawing way more that 2 of the amps should draw.  Shut down and checked the amps while not connected to anything and all was well.  But when I looked at my reference GarminIII+ it was not tracking.  None of my GPS receivers were working.  Checked the Garmin using it's own antenna and it worked.  Checked outside and the mast top Motorola ANT97 is dead, it got fried by the 18 Volts, normally runs on +5.  Have a Timing 2000 on order.

What went wrong?
Ans: the open I saw was the routing diode in the 4-way divider, once the voltage got above 0.6 V the 18 volts was sent up to the inline amp and to the mast head active antenna.
The fix:  Add DC blocks (RS 15-1259) to all of the 4-way divider outputs, except for the one that powering the mast head antenna and in line DBS amp.

The system now looks like this:

• Motorola hocky puck GPS antenna at the top of a 10 foot TV antenna mast mounted at the top of a two + story chimney.

• Maybe 25 feet of cable down the side of the chiminey where a DBS satellite amplifier is getting 5 volts drive (way under volatge, but it's still making a noticable improvement.
• Maybe 25 mor feet of TV coax to the 4-way divider.  Which has:
• Motorola Oncore VP+ GPS receiver powering the in-line amp and the mast mounted active antenna, used for TAC32 GPS
• Motorola Oncore VP+ GPS receiver decitaded to driving the Stanford Research Rb oscillator
• Garmin III+ powered by the external cable showing what satellites are up and relative signal strengths.
• Two each DBS satellite in-line amplifiers, now underpowered by an in-line TV amplifier wall wart feeding a Trimpack AN/PSN-10 GPS receiver.
  

Back to Brooke's Products for Sale,  Electronics, Home page

This is the 06813 hits since May 04 2007 time this page has been accessed since since 1 Nov. 2001.