n9ik’s radio blog

I’ve finally gotten around to completing the Rock-Mite 40 transceiver kit. It was fun to put together, in spite of my problems with my shaking hands and the difficulty it causes with putting components and wires on the board and connectors. Below are a few photos:

The RM board is fully “stuffed”, waiting for wires.

 

In this picture of the RM at board level, you can see that I’ve used SIP sockets as sockets for the crystals, allowing me to change out the crystals with 7.040 MHz crystals, which are for the other 40meter QRP calling frequency.

 

Another board level close-up.

 

Here some of the wires have been added.  The crystals have been removed, and you can clearly see the SIP sockets at lower left and upper right on the board.

 

To fit the FCC’s newer (June 2004) spurious emission requirement, a 150pF cap and a 3.3 uH RF choke should be installed in series between the center conductor of the antenna connector and the board. The RF choke lead would not fit through the through-hole on the board, so I soldered it directly to the antenna connector, and put the capacitor on the board. The antenna connector and the caps position on the board are close enough that the leads of the choke and capacitor can be soldered directly together with out using the coax. Eventually, I ended up breaking the lead off of the choke, and since I don’t have a replacement I removed it and the cap and used coax to connect the board to the antenna connector. I’ll put the choke and cap back on when I can.

 

It’s a tight fit with the board and connectors all wired and installed in the Mighty Box enclosure. Here you can see that the leads for the two crystals (lower left and upper right) needed to be bent over so that the crystals would fit. If they had been soldered directly to the board instead of using sockets, they would probably have been fine standing up straight.

 

Ready for the bottom cover to be screwed into place.

 

Front view of the completed RockMite. Left to right, audio gain, switch, phones. The switch is used to toggle off-set frequency and control the internal keyer.

 

Rear view of the completed RockMite. Left to right: key, antenna, power.

 

If/when I get a clear label cartridge for my Brother P-Touch labeler, I will add labels to the RM case.

Now, to make some contacts!