The Ten-Tec 1340 is a 40 Meter (7MHz) QRP transmitter. QRP means that the transmitter produces <5 watts of output power. The 1340 is one of several 13xx series kits from Ten-Tec. The kit includes roughly 250 components including several IC's, toroids, and passive parts. It took roughly 15 hours to build the radio from the manual.
I can get roughly 3 watts out of my kit which is within range of what Ten-Tec gives for this radio. The output power tends to vary with each version of the 13xx series. After completing the kit I made many contacts with CW (Morse code). This is my favorite mode of operating and it is very efficient as well. A particularly memorable contact I made was with an amateur operator in Asiatic Russia with only 3 watts of RF power!
It didn't take long for me to modify the Ten-tec 1340. I have performed many modifications to it to improve its performance and ease of use. The first change was with the audio capacitor. The 13xx series tends to have a "clicking" when transmitting. Probably due to the transciever not having a CW tone generator to listen to when transmitting. Instead, the 13xx series samples a portion of the RF output and uses it as the sidetone. A simple switch to a higher capacitance smoothed out the sidetone and took a good amount of the click out of the audio. I also installed another kit into the radio. I purchased and built a NORCAL Keyer kit and installed the board as seen in the photo in the top right corner. The leads for the CW paddles can be seen going to connectors mounted on the chassis. This allows the radio to be used with CW paddles and generate electronic "dits" and "dah's". With electronic keying speeds of >20 words per minute are possible.
The chassis was also modified. I am not a fan of PL-259 connectors which are also known as UHF connectors. They are pretty much only used my amateur radio operators these days and are not anywhere near efficient at UHF! While they are decent when used for frequencies <30 MHz, the connector does not provide constant impedance. Due to the center conductor of the coaxial cable being soldered to the center pin, which is an open cylinder, the shape of the solder on the tip varies and can change the impedance. Therefore I have been trying to build all my projects with BNC and N-Type connectors. I modified the connector mounting with a piece of scrap aluminium to mount a female BNC connector. It worked perfectly and has proved to be sturdy.