EME168 Bias Tee Kits

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EME168 Description:

There are a number of different EME168 Bias Tee ( DC Power Injector ) products available to cover the HF to UHF bands. All are constrcted on the EME168 board that uses a stripline and flange mounted RF connectors for lowest loss. A Hi-Q low loss 1kv capacitor is used along with a low loss choke allowing RF power levels of at least 500 Watt PEP on the VHF to UHF bands.

EME168-HF:

The EME168-HF Bias Tee was designed to suit the EME162 HF Active Antenna, and is for receive only applications. This Kit has been designed to be used with a HF communications receiver, or on the auxiliary RX antenna connection that is available on many late model HF transceivers. RF power cannot be transmitted through the EME168 HF bias tee. HF Application Block Diagram

EME168-VHF:

The EME168-VHF version was designed to suit the EME157 6M, and 2M preamplifier Kits and and will handle at least 100 watts. This Kit has been discontinued and Replaced with the EME168-6-2 and the EME168-2-70 which have higher RF power handling. VHF Application Block Diagram

EME168-6-2:

The EME168-6-2 version is suitable for use between 40 and 200MHz, and has been designed to suit the new EME220 series 6 and 2M band preamplifier Kits. The design uses a high Q RF decoupling coil and a high quality low ESR 1kV DC decoupling capacitor, so it will easily handle 500 Watts PEP. This product is particularly suitable as an interface to allow transceivers to be able to switch power through a coaxial cable to a remote preamplifier. VHF Application Block Diagram

EME168-2-70:

The EME168-2-70 version is suitable for use between 100 and 500MHz, and has been designed to suit the new EME220 / 221 series 2M and 70cm preamplifier Kits. The design uses a high Q RF decoupling coil and a high quality low ESR 1kV DC decoupling capacitor, so it will easily handle 500 Watts PEP. This product is particularly suitable as an interface to allow transceivers to be able to switch power through a coaxial cable to a remote preamplifier. VHF Application Block Diagram

EME168-70-23:

The EME168-70-23 version is suitable for use between 400 and 1500MHz, and has been designed to suit the new EME221 series 70 and 23CM band preamplifier Kits. The design uses a high Q RF decoupling coil and a high quality low ESR 1kV DC decoupling capacitor, so it will easily handle 500 Watts PEP. This product is particularly suitable as an interface to allow transceivers to be able to switch power through a coaxial cable to a remote preamplifier. VHF Application Block Diagram

 

Kit Constructors Alert:

1/ There are no current alerts.

EME168-HF Construction Notes:

The EME168-HF is a receive only HF Bias Tee that was designed to power the Mini-Kits EME182 HF Active Antenna via the coaxial cable. The Bias Tee can be used either with a HF communications receiver, or with a modern HF transceiver that has a separate RX Antenna socket on the rear. The circuit incorporates a RX to TX changeover circuit so that power can be cut to a HF active Antenna when in transmit mode, to protect the active circuit. The Bias Tee was not designed for transmitting any RF power through it, so should not be used for this purpose. The Bias Tee has a low loss and provides a frequency range of 100kHz to over 300MHz.

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EME168-HF Rear View
Rear view of the EME168-HF Bias Tee Kit. The board is designed to fit a Hammond 1590A die cast enclosure. Click the picture for a larger view
EME168-S11-1A
The above plot shows the S11 return loss of the EME168-HF from 0 to 60MHz
HF-S21-1A
The above plot shows the S21 through loss of the EME168-HF from 0 to 10MHz
HF-S21-2A
The above plot shows the S21 through loss of the EME168-HF from 0 to 300MHz
EME168-HF-DC
Fitting 2.1mm DC socket and PTC fuse
EME168-HF-RFC1
How the RFC choke is fitted to the board
EME168-HF-PTT
PTT connection from the RCA socket to the board

EME168-VHF Construction Notes:

The EME168-VHF was designed to suit both the 6 and 2M bands. The Bias Tee was specifically designed to be used with VHF transceivers that do not have the ability to switch DC power out of the antenna socket to power masthead preamplifiers. The design uses a wound toroid as a choke which provides very low loss, and covers the complete 50 to 300MHz VHF band. The Bias Tee has been designed to handle at least 100 Watts. This Product has been discontinued and replaced with the EME168-6-2, ( 6m and 2m bands ) and EME168-2-70 ( 2m and 70cm bands ).

THIS PRODUCT HAS BEEN DISCONTINUED

EME168-1A Front View
Front View of the EME168-VHF Bias Tee with N type connectors
eme168-3A Rear View
Rear view of the original EME168-VHF only Bias Tee Kit. The board is designed to fit a Hammond 1590A die cast enclosure. Click the picture for a larger view
EME168-2-70-DC
Fitting 2.1mm DC socket and PTC fuse
EME168-2-70-RFC1
How the RFC choke is fitted to the board
EME168-2-70-PTT
PTT connection from the RCA socket to the board
EME168-vhf-S21-Plot
The above plot shows the S21 through loss of the EME168-VHF from 0 to 300MHz
EME168-vhf-S11-Plot
The above plot shows the S11 return loss of the EME168-VHF from 0 to 300MHz
 

EME168-6-2 Construction Notes:

The EME168-6-2 bias tee is designed to cover the 6m, 4M and 2m bands, and has a wide 30 to 200MHz frequency range.

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EME168-1A Front View
Front View of the EME168-6-2 Bias Tee with N type connectors
EME168-6-2-Top View
Rear view of the EME168-6-2 Bias Tee. The board is designed to fit a Hammond 1590A die cast enclosure. Click the picture for a larger view
EME168-6-2-RFC1
Fitting of the inductor RFC1
EME168-6-2-RFC1
Fitting of the inductor RFC1
EME168-2-70-DC
Fitting of the DC jack and RXEF030 Polyswitch
EME168-6-2-S21
The above plot shows the S21 through loss of the EME168-6-2 from 20 to 200MHz
EME168-6-2-S11
The above plot shows the S11 return loss of the EME168-6-2 from 20 to 200MHz

EME168-2-70 Construction Notes:

The EME168-2-70 bias tee is designed to cover both the 2m and 70cm bands, and has a wide 100 to 500MHz frequency range.

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EME168-1A Front View
Front View of the EME168-2-70 Bias Tee with N type connectors
EME168-2-70-Top View
Rear view of the EME168-2-70 Bias Tee. The board is designed to fit a Hammond 1590A die cast enclosure. Click the picture for a larger view
EME168-2-70-RFC1
Fitting of the inductor RFC1
EME168-2-70-RFC1
Fitting of the inductor RFC1
EME168-2-70-DC
Fitting of the DC jack and RXEF030 Polyswitch
EME168-2-70-S21
The above plot shows the S21 through loss of the EME168-2-70 from 50 to 550MHz
EME168-2-70-S11
The above plot shows the S11 return loss of the EME168-2-70 from 50 to 550MHz

EME168-70-23 Construction Notes:

The EME168-70-23 bias tee has a wide 400 to 1500MHz frequency range and is designed to cover both the 70 and 23cm bands.

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EME168-1A Front View
Front View of the EME168-70-23 Bias Tee with N type connectors
EME168-70-23-Top View
Rear view of the EME168-70-23 Bias Tee. The board is designed to fit a Hammond 1590A die cast enclosure. Click the picture for a larger view
EME168-70-23-RFC1
Fitting of the inductor RFC1
EME168-70-23-RFC1
Fitting of the inductor RFC1
EME168-2-70-DC
Fitting of the DC jack and RXEF030 Polyswitch
EME168-70-23-S21
The above plot shows the S21 through loss of the EME168-70-23 from 50 to 2000MHz
EME168-70-23-S11
The above plot shows the S11 return loss of the EME168-70-23 from 50 to 2000MHz

Changes and Modifications:

1/ The EME168-VHF has been discontinued and replaced with the EME168-6-2 ( 6 and 2m bands ), and EME168-2-70, ( 2 and 70cm bands ).

2/ Kits after September 2016 have had the 10uF capacitor removed on the drain of the NDT2955 MosFET as it is not required, and the 1206LO16 Polyswitch removed and replaced with a wire link. The RXEF010 Polyswitch can also be replaced with a RXEF030 ( 300mA hold ) type is required for more current.

3/ Kits after October the 25th 2016 have had the BC847 transistor that drives the NDT2955 MosFET replaced with a 2N7002 MosFET. This improves the switching when the PTT1 connection is used with some Transceivers including the Kenwood TS2000.