Mini-Kits produce a number of Kits that are suitable for many of the older Mitsubishi M series, and the new RA series modules. The EME44 is an Amplitude Modulated Double Sideband Television transmitter for the 70cm Amateur band.
In February 2010 the Mini-Kits EME76 PC board has been replaced with the EME176. The boards are essentially the same except for the addition of an optional attenuator on the input, and some changes to the track layout to allow for TX switching of the Bias.
For the latest service bulletins and data sheets, please see the Mitsubishi Semiconductors website.
Mitsubishi has released RA series modules with a M1 prefix that have a flat non stepped heatsink mounting and a metal cover. Please read Mitsubishi's service bulletin AN-GEN-042D and follow their procedures for mounting of these modules.
All Previous Kit Notes have been replaced in February 2010 with the following changes. Mini-Kits no longer recommends sanding the Mitsubishi HS2 packaged modules flat, and now only recommends following Mitsubishi's recommendations as per their application Note: AN-GEN-042D. If you have been supplied with Kit notes that recommends sanding the module, then please disregard this and do not modify or sand the module in any way. Please read Mitsubishi's service bulletin AN-GEN-042D and follow their procedure.
Pictures show how the low pass filter inductors are wound and mounted on the board. Take note of the coil winding direction and how they are mounted above the board. The pictures also show how RFC1 is wound and mounted. The picture shows 1.5 turns but can be 1.5 to 2 turns and is not critical. The Pictures and RF design shown is copyright Mini-Kits.
Pictures show how the low pass filter inductors are wound and mounted on the board. Take note of the coil winding direction and how they are mounted above the board. The pictures also show how RFC1 is wound and mounted. The picture shows 3.5 turns but can be 3.5 to 4 turns and is not critical. The Pictures and RF design shown is copyright Mini-Kits.
1/ There are no current alerts for this Kit. Please see the Kit changes section below for any issues..
1/ This applies to all RA series Module Kits. The recommended mounting of the Mitsubishi HS2 packaged modules has now changed to the recommended mounting procedure supplied by Mitsubishi in service bulletin AN-GEN-042-C. Modules should no longer be sanded flat due to the possible damage that can be caused if they are over heated. A very flat heatsink that has a very smooth surface with no scratches is required to mount the module. Mini-Kits recommends the use of a Pentium P4 fan assisted heatsink that will dissipate up to 100 Watts heat for all modules under 30 Watts output, and as low as 20% efficiency. These can be found on old Pentium mother boards in computer recycling shops.
2/ To use the Amplifier with a Sequencer like the EME66, it is suggested that the board is modified to switch 12 volts to the input of the 5v regulator. The PC board track between the 0.1uF capacitor and 100uF capacitor needs to be cut with a scalpel to disconnect the main 12 volt power from the regulator. The RA series modules being MosFET types, can be connected to 12 volts permanently, and the bias switched to turn it on and off. The delay 3 output from the EME66 sequencer is connected to the input of the 5v regulator.
3/ If the PA is mounted in a shielded metal box then the feed through capacitor that is normally soldered on the board can be soldered in a hole in the side of the box to feed the main power through to the board. Another feed through could also be used if you are switching the bias supply.
4/ An Email from Wolfgang, DK1OV and Heinz, DJ2IV on problems and repair of the RA18H1213G modules.>
We want to inform you about our project 23-cm PA with the modules, which we got from you. We built two amplifiers, each with two modules in parallel. We mounted the modules onto a 5mm thick piece of copper with the dimensions 100 x 160 mm (about 4 x 6.5 inch) and this onto a big aluminum cooler. This was a lot of work but we did it because you told me to be careful with too much power output due to thermal stress. The amplifier worked perfect first and we got 80 W output at 12,5 V supply. But after a few minutes the power dropped to less than a half, one of the modules failed. The quiescent current was 2 A at the failed module the other module draws 3.5 A. We opened the failed module and found, that the first two FET's didn't get drain-voltage. The supply-line was interrupted near to a blocking-C, in one of the modules the most right one, in the other module in the middle. After we soldered a thin copper wire along the supply-line, the modules worked well again and we had no longer problems until now. We tested the amplifiers for hours with maximum output. The maximum power output is more than 80 W at 12.5 V, it drops to 75 W when the amplifier gets warm and remains constant then. In DATV we get about 20 W linear output with 35 dB inter modulation suppression. We are very satisfied with the result.>
1/ Please refer to the Kits notes as they are up to date.