8-way Amplified/Isolating GPS Distribution


Measured S21 (30 dB offset, gain is higher by 30 dB)

Features

  • Supports up to 8 GNSS devices from a single L1 GNSS Antenna
  • Provides more than 60 dB differential and common mode  isolation for LF -HF devices. This is particularly important for a bank of KiwiSDRs.
  • GNSS  Antenna (puck) can be powered by GNSS device #1
  • Devices 2-8 can also receive an isolated GNSS antenna signal
  • ~8-12 dB of low noise, filtered gain to each of the additional outputs
  • Low noise preamplifier provides similar performance to each device
  • Bandpass filter reduces susceptibility to non-GNSS signals
  • Four-layer, through-hole plated, silk-screen printed PCBs

    • Operation

    The first versions of this isolating distribution board I sent out required power for the on board amplifier to be passed in from a functioning GPS receiver/device on input #1. This path does not have isolation because of the need for DC current to pass. In the present version of the board I have added an on-board LDO and made it possible to cut a couple of traces so that an external 5-20V power source may be used instead.

    There is also a resistor that can allow the external supply to be 8V or more for some Antennas which require it. This is a rare situation.

    if it is present, REMOVE THIS RESISTOR BEFORE USING EXTERNAL POWER IF YOU DO NOT WANT THIS HIGHER VOLTAGE OPTION !!!(v1.1 only)

    I test all outputs before sending so hopefully everything will continue just fine.

    If there are any questions, please ask and I will try to post any answers that might be relevant to others on this site.

    It's not particularly complicated or interesting but here's a schematic and a PDF.
    .
    There are three cases for operation:
    Puck antenna receives power from GNSS DUT #1 R3 not present , Nothing need by done
    Puck antenna receives External power 5-16V at W1 R3not present , cut jumper A
    (uncommon) External power 8V, special antenna Add R8, cut both Jumpers A&B



    Material List

    What you will need to build this hardware

    Item Description

    Provider

    Source Code

    Notes

    Approximate Material Cost

    (excludes setup fees and shipping)

    Assembled GNSS PCB

    Download GNSS PCB Kit Files

    Download GNSS PCB Source Files
    		US$30

     Enclosure

    eBay

    		US$6

    Enclosure Front Panel

    Download GNSS PCB Front Panel Kit Files

    Download GNSS PCB Front Panel Source Files
    		US$1

    Enclosure Rear Panel

    Download GNSS PCB Rear Panel Kit Files

    Download GNSS PCB Rear Panel Source Files
    		US$1


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