GCR2 Transmitter

Modified Updated Universal Transmitter (designed by W7ZOI)

The transmitter is finally finished (05/10/07)!

The schematic below details the modifications that I made to W7ZOI's Updated Universal Transmitter. It shows the PA section only. Q1 and Q2 are Class A amplifiers and Q3 operates in Class C. Basically I made three modifications:

Power Amplifier Board

Next is a photo of the power amplifier board for the transmitter. The buffer was built using SMT parts while the rest of the board was constructed of primarily leaded components. The board traces were cut using a dremel and a diamond burr. I also substituted a 2sc1307 transistor (which I had in my junk box) for the two final stages. A primary difference is that they have metal tabs which are continuous with the collector pin of the transistor. Hence, they needed to be insulated from ground and this was accomplished by cutting two large pads on the board. They can be easily replaced if they don't work as substitutes. (Additional Note: While these transistors worked fairly well, I ended up using the 2sc5739 units as per W7ZOI's original design in the final version of the transmitter. The 2sc5739's can be seen in the last photo on this page on the TX board.)

The Low Pass Filters

The low pass filters are those printed in the IQPro VFO manual. They will be switched in and out via latching relays through the control circuit of the VFO. The first photo is of the filters installed on the board without the relays. As you can see, I dremeled three pads for the common connections: the relay coils, the transmitter and the antenna.

Completed Transmitter

Here is a brief description and a photo of the completed GCR2 transmitter.

Transmitter Output Per Band
1.8 MHz to 14 MHz = 4.5-5 watts
18 Mhz = 2 watts
21 MHz = 1 watt
24 MHz = 300 mW
28 MHz = 100 mW

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