EME195 Series Receive Bias Tee

EME195 PC Board Description:

The EME195 Series RX bias tee ( DC Power Injector ) Kits are suitable for powering Receive Preamplifiers from 0.5MHz to 2GHz via a coaxial cable. There are currently three Kits to suit frequency ranges from 0.5 to 100MHz ( EME195H ), 30 to 500MHz ( EME195V ), and 300MHz to 2GHz ( EME195U ). All have been optimized to cover each specific band, for the lowest loss and return loss.

The board is fitted with reverse polarity and PTC protection to safeguard against any short circuits on the RF/DC output connection with a maximum DC voltage and current of +25vdc @ 160mA. The design uses SMD Inductors and capacitors that have been optimized for the lowest RF return loss across the bands.

Kit Constructors Alert:

1/ If you are constructing the full Kit into the die-cast enclosure, in some cases the DC socket may not work and will require some tinned copper wire soldered from the centre ground connection to the PC boards ground.

EME195 KIT Notes:

The Kit is quite straight forward to construct, and a pre wound SMD inductor is now used compared to a Toroid on the previous EME181 bias Tee Kits. All three Kits are similar to the pictures below and only the value of the inductor and capacitors are different. The SMA connectors need to be soldered on both sides of the board for the bests grounding and return loss. BUY THIS PRODUCT

  • EME195U Top View
    The picture shows the built EME195 board Kit U for 300MHz to 2GHz.
  • EME195U Module Board
    The picture shows the built EME195B-M Module board for 300MHz to 2GHz.
  • EME195H Enclosure View
    The picture shows the built EME195H-ENC for 0.5 to 100MHz. Solder some tinned copper wire from the DC sockets centre tab connection to the PC boards ground.
  • EME195U Enclosure View
    The picture shows the built EME195U-ENC for 300MHz to 2GHz
EME195 Kit Tests:

  • EME195H S11 Return Loss
    EME195H S11 return loss with the bias tee terminated into a 50ohm load showing a wide operating frequency range of 0.5 to 100MHz.
  • EME195H S11 Return Loss
    EME195H S11 return loss with the bias tee terminated into a 50ohm load showing a wide operating frequency range of 0.5 to 100MHz.
  • EME195V S21 Loss
    EME195V S21 through loss showing that it is usable from at least 0.1 through to 1GHz.
  • EME195V S11 Return Loss
    EME195V S11 return loss with the bias tee terminated into a 50ohm load showing a wide operating frequency range of 0.1 to 1GHz.
  • EME195U S11 Return Loss
    EME195U S11 return loss with the bias tee terminated into a 50ohm load showing a wide operating frequency range of 0.15 to 2GHz.
  • EME195U S21 Loss
    EME195U S21 through loss showing that it is usable from at least 0.15 through to 1GHz.
Mounting into a Die cast Enclosure:

This is for advanced constructors that have experience and access to a workshop with metal working tools. The basic tool requirement are a drill press, Vice, M1.5, M3, M8, and 1.4 inch drill bits, metal punch, hammer, and steel ruler.

  • EME195-Encl-1
    EME195H-ENC Mounted in a Hammond 1590H Enclosure.
  • EME195-Encl-2
    Alignment for drilling the 1/4" holes for the SMA connectors, and the 2.1mm DC connector.
  • Hammond 1590H Enclosure
    Shows a completed EME195V Bias Tee in a Hammond1590H Enclosure
Mounting Procedure:

There can be some variations with connectors, and mounting hardware thicknesses that may require some experimentation when mounting boards into enclosures.

  • Construct the PC board as per the EME195 Kit construction notes but DO NOT fit the SMA connectors to the board. Connect a short 10cm length of Red hookup wire to the power connection on the bottom side of the board.

  • Carefully mark and drill the two 6.5mm, ( 1/4" ) and single 8mm holes in the die cast enclosure as shown in the picture above.

  • Loosely fit the two SMA49 connectors to the enclosure in a position that will allow the PC board to be slid between the guides on the rear of the connectors.

  • Turn the PC board and SMA connectors in the enclosure until the board sits in its normal horizontal position. Very lightly tighten the SMA connectors, and then align the connector pins carefully with the PC board strip lines.

  • Solder the top of the PC board to the two SMA connectors, and then loosen the nuts on the connectors and rotate the board 180 degrees in the enclosure. Solder the SMA connectors to the bottom ground plane side of the board.

  • Realign the PC board in the enclosure in its final position, and then firmly tighten both nuts on the SMA connectors.

  • Fit the 2.1mm DC socket to the enclosure. Solder the Red and Black wires for power from the board to the DC socket connections as shown above. The wires should be routed under the board so that it does not affect the RF operation of the circuit.

  • This concludes the construction of the complete boxed Kit which can now be tested.

  • Please note that when tightening up the nuts on the SMA connectors, to be careful not to twist the PC board which could crack the sad components. When connecting cables to the sockets, only do up hand tight to avoid twisting the connectors that could place strain and twist the PC board.

Changes and Updates:

1/ If you are constructing the full Kit into the die-cast enclosure, in some cases the DC socket may not work and will require some tinned copper wire soldered from the centre ground connection to the PC boards ground.