This new kit from KJ7UM is a thermatron version of the original one transistor Michigan Mighty Mite (MMM), a simple CW QRP 80M (or 40M) crystal controlled transmitter. The original version was intended to be very simple and very inexpensive utilizing a low cost TV color-burst crystal at 3.579 MHz. This version uses a 6C4 thermatron and is designed to transmit on the CW portion of the 40M band.

The photo shows the TMMM mounted on a small piece of plywood with an optional HV power supply (see below).

More details and history of the MMM can be found on Bill Meara's soldersmoke blog.

Since it’s a thermatron version, I call it the TMMM. The purpose of this kit is to familiarize new or existing hams with simple vacuum-tube homebrew construction techniques by building a simple thermatron circuit that will actually make contacts.

A link to a full length video of the design and construction of an early version of the TMMM is included in the assembly instructions (youtu.be/a_NjAOWDW0o). The video takes you through how to design and build the circuit from scratch. The kit is an improved version of the hollow-state MMM in the video. The video is based on my world famous book, Hollow-State Design, by me, available on eBay for $39.95.  Highly recommended.

The power supply kit supplies 190V DC and 6.3V AC.  You can also build one yourself. The TMMM needs 6.3 V (AC or DC) at 150 mA for the filament and anywhere from 150 to 250 Volts for the B+ (6C4 plate circuit). 

Required power: 6.3V AC or DC at 150 mA, Up to 300V (typically 250V) DC at 25 mA

Thermatron: 6C4 (tested)

Output power: about 350 - 400 mW into a 50 ohm load. It depends on the plate voltage you supply the

6C4. Max plate voltage is 300V.

Transmit Frequency: the kit is supplied with a crystal in the CW portion of 40M (7030, 7040, 7055)

Second harmonic level: about -39 dB from carrier level.