EME210 16 Watt HF Amplifier Kit

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EME210 Module Description:

The Mini-Kits EME210 is a 16 Watt 1 to 50MHz Amplifier that uses a linear high gain transmit driver, and 2x RD16HHF1 MosFETs, and was designed for the M1 Transceiver. The amplifier is suitable for all modes and can be used as a low power QRP amplifier, and as a driver for a higher power amplifier using 2x RD100HHF1 MosFETs. The amplifier has around 45dB gain so can easily be driven to full power, 16 Watts ( +42dBm ), with as little as 0.50mW ( -3dBm ). For linear operation, it is recommended to keep the CW power set to around 10 Watts for a linear 16Watts PEP output on SSB.

The module features solid state diode switching of the RF to bypass the amplifier in receive mode, and has a flat -1.5dB transmit frequency response from 1 to 50MHz.

The module is controlled through a single 16 Pin IDC header connector, making it easier to interface to logic circuitry. See the M1 Transceiver Block diagram for the connections to this module.

The EME210 is a part of the M1 series building blocks to construct a high performance M1 HF Transceiver. The M1 HF Series Kits have been designed to allow easy construction due to the use of mainly leaded components for those that don't like surface mount devices. Modern SMD components are only used when required due to availability of components, or for better performance. The RF modules are all designed with a 50ohm impedance making it easy to interconnect with the other M1 series modules, and your own home brew circuit designs.

Some of these performance figures may change with future tests.

Kit Constructors Alert:

EME210-Rev1 / 2 Board Kits

1/ There has been some problems with instability or low gain with the GALI-84 driver. This appears to be a problem with the decoupling capacitor C6 not having a direct path to ground. The solution is to fit a conventional leaded 0.1uF monolithic capacitor under the board from the junction of C6 and L4 to ground. The modification can be found here and the ground connection used is the RF input connectors ground connection to the board.

2/ I have seen failure of the GALI-84 driver and BAR64-05 diode a few times which I now suspect to have been problems with the speed of the switching of both the +8V / RXA and +8V / TXA logic. I think that the RX bypass on the EME210 PA was allowing some high RF levels back into the input of the BAR64-05 and Gali-84 driver destroying them. The main problem may have been the EME208 Modulator board that has a 100uF filter capacitor on the +8V/TXA supply to the microphone amplifier. A modification has been made to the EME208 module to fix this problem. There were also issues with the slowness of the +8V / RXA when going to TX mode that was traced to the EME210 module. The following components have been changed to speed up the RX logic. R1 has changed to 220R, C5 to 0.1uF, and R3 to 1k. Some testing will now be required to see if this issue is fixed for good.

EME210-Rev1 / 2 Board Kit Notes:

The pictures below are a final revision so should be carefully followed in construction. Some components values shown in the pictures may not be the same as supplied with later Kits due to changes and or improvements. BUY THIS PRODUCT

EME210-Rev1 Top View
Top view of the EME210-Rev1 Board

This version uses a Ferrite toroid for L4 that requires the C6 modification

EME210-Rev1 Bottom View
Bottom view of the EME210-Rev1 Board

The picture shows the bottom view of the EME210-Rev1 Kit

EME210-TF1-A
Transformers TF1 showing the windings C to D to E
EME210-TF1b
Transformers TF1 showing the windings A to B.
EME210-TF2-3-A
Transformers TF2 and 3 showing the windings.
EME210-TF2-3-B
Transformers TF2 and 3 showing the windings
RD16HHF1- Mounting-A
Mounting of the two RD16HHF1 MosFETs.
RD16HHF1- Mounting-A
Module removed from Heat-sink showing the MosFETs.
C6-Modifiction
Fit external 0.1uF C6 for the GALI-84 driver mod.

EME210 Performance Tests:

EME210-RX-Bypass-Loss
The above picture shows the loss in receive bypass mode through the diode RF switch.
EME210-RX-TX-Loss
The above picture shows the attenuation provided though the receive bypass by the diode RF switch when in transmit mode.
EME210-Driver-Gain
The above picture shows the gain of the GALI-84 driver stage from 1 to 100MHz
EME210-RD16-Gain
The above picture shows the gain of the 2x RD16HHF1 amplifier stage using 470R feedback resistors from 1 to 100MHz
EME210-RF Output
The Red plot shows the RF output power of a typical amplifier when using a 180pF capacitor in the C17 position to improve performance on the 10 to 6M bands. The Blue plot is the saturated RF output power.
EME210-Gain-C17-Not-Fitted
The above picture shows the gain of the amplifier with a No capacitor fitted into the C17 position. Add 20dB to the readings due to the use of a 20dB attenautor.
EME210-Total-Gain-330pF
The above picture shows the gain of the amplifier with a 330pF capacitor fitted into the C17 position. Add 20dB to the readings due to the use of a 20dB attenautor.
EME210-Total-Gain-180pF
The above picture shows the gain of the amplifier with a 180pF capacitor fitted into the C17 position. Add 20dB to the readings due to the use of a 20dB attenautor.

Kit Changes and Modifications:

EME210-Rev1 / Rev2 Board Kits

1/ There has been some problems with instability or low gain with the GALI-84 driver. This appears to be a problem with the decoupling capacitor C6 not having a direct path to ground. The solution is to fit a conventional leaded 0.1uF monolithic capacitor under the board from the junction of C6 and L4 to ground. The modification can be found here and the ground connection used is the RF input connectors ground connection to the board.

2/ I have seen failure of the GALI-84 driver and BAR64-05 diode a few times which I now suspect to have been problems with the speed of the switching of both the +8V / RXA and +8V / TXA logic. I think that the RX bypass on the EME210 PA was allowing some high RF levels back into the input of the BAR64-05 and Gali-84 driver destroying them. The main problem may have been the EME208 Modulator board that has a 100uF filter capacitor on the +8V/TXA supply to the microphone amplifier. A modification has been made to the EME208 module to fix this problem. There were also issues with the slowness of the +8V / RXA when going to TX mode that was traced to the EME210 module. The following components have been changed to speed up the RX logic. R1 has changed to 220R, C5 to 0.1uF, and R3 to 1k. Testing over time has resulted in no further failures so these changes appear to have fixed the issue.

3/ For increased output power on the 10 to 6M bands, a 180pF NPO type capacitor that is at least 250vdc rated can be added to position C17. This has not affect on the output power on lower frequency bands, and does not change the gain. The capacitor modification resonates the output transformers for better efficiency on the higher frequency bands, which produces more output power.