VK3YE amateur radio pages

'Micro 40' 7 MHz DSB transceiver


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Material may not be reproduced without permission.



The 'Micro 40' is a simple DSB voice transceiver for the 7 MHz amateur band. A single NE602 forms both the transmitter's balanced modulator and the receiver's product detector. Because it's an active device the receiver has higher gain than those with passive mixers such as the 'Beach 40'.

It is similar to other NE602-based DSB rigs by M0DAD and ZL2BMI. It was described in Lo-Key in 2011 but an even more detailed description and circuit appears in AA7EE's link below. Its receiver is particularly good as demonstrated on the 'Twice the Bedlam' and AA7EE videos.

Twice the Bedlam (testing the receiver before the rest was built)

Part 1 (introduction)

Part 2 (more tests)


A constructional article on the Micro 40 appeared in Lo-Key June 2011, published by the VK QRP Club.

Micro 40 links

Visit the following for others' experiences in constructing this rig:

* AA7EE (comprehensive write-up and circuit)
* M0DAD (similar design)
* ZL2BMI (similar design)

Note: This simple DSB rig is not to be confused with the Micro 40C and Micro 40S by YD1JJJ which are more advanced filter-based superhet transceiver kits for CW and SSB.