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May 24, 2024. Forget that TIA Stuff!


 Bi-Lateral MMIC Module



Todd, K7TFC in his recently published Newsletter announced work being done on providing a board that will house the MAR6+SM MMIC device. The beauty of that jewel is the low Noise Figure of 2.3dB, gain to 2GHz, rated at 20dB and 50 Ohms in/out thus termination insensitive!

In 2010, I published my very 1st QRP Quarterly article which involved a 20M SSB Transceiver employing six MMIC devices in a bi-lateral configuration.


For me having a 1st published article this was huge, but more importantly it proved the viability of the MMIC devices as a building block for homebrew ham rigs.

Below is a you tube video. The rig worked great but the Varactor tuned VFO was crap. The published article had a Si-570 PLL and I have never looked back. 

The Surface Mount issue some 15 years ago was a pox on more widespread duplication of this project. A bridge too far and how many hams have a CNC machine in their garage?




The 20M rig used the AG-303-86G MMIC which is now obsolete. But the MAR6+SM would work as a substitute. K7TFC's in work board mount will now make it possible to duplicate the radio. 

The MAR6+SM needs but two caps, a dropping Resistor and a small RF Choke. In the 1st photo is a layout for a bilateral circuit using the AG303-86G (similar MMIC) but that same layout will work with the MAR6+SM. The 2nd photo is the bilateral schematic.

The unit cost is $1.83 from Digi-Key and for most hams the Surface Mount would be a constraint. But a Board for the device in work from Todd will remove that mounting impediment.

Three such Bilateral Amp boards as in the 20M MMIC SSB would fill the need for a combo Rx RF Amp and TX Pre-driver, with a second set of two bilateral boards providing a bi-lateral IF module. Roughly less than $11 will provide 6 units. 

I used 5 VDC on board regulators to power the devices and simply powering on a unit is all that is needed for bi-lateral operation.

It is with regret that my time is so limited as I would love to rebuild that 20M MMIC using some of the newer devices (Xiao RP2040) and technologies. K7TFC's efforts will now make it possible for you to do that.

Always slightly ahead...

73's
Pete N6QW


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