LARCSet Inhaling RF
Thanks to VU2ESE, a brand new 40M SSB/CW Transceiver kit is available for sale which can be found here. The price is $39. Boasting an Analog Varactor VFO and 5-Watt output, it is a dream come true. This is how you stick it to Qualcomm and their new ToS.
The architecture has roots back to the Bitx 40 rigs. I looked at the schematic and fantasized the possibility of customization with the addition of USB to facilitate FT-8. My brain also wandered into thoughts of changing out the BPF and LPF to move it to 20M. Those changes may not be feasible, but I always think big.
The IF is at 11MHz with the VFO at 4MHz and is subtractive to yield 7MHz operation. This is a case of sideband inversion. My mindless thoughts were if you added the VFO (versus subtracting) to the IF that would give you 15 MHz and padding down the VFO to 3MHz would give you 20M and automatically on USB without any changes to the BFO.
Moving the varactor tuned VFO to 3 MHz would make it even more stable with regard to any frequency drift. With the IF a 3.141MHz LO puts you on 14.2 MHz. Caution, a spur analysis would have to be done to assure some odd ball combo of frequencies does not end up in the 20M pass band.
At this price point it is currently offered only as a kit. Some clever entrepreneur might offer build services and so that may open the door to those who have two left thumbs.
This is a great kit based on the solid well-known Bitx topology and at an affordable price. Group buys at reduced pricing is another bonus.
Them that know can make things go.
73'sPete N6QW
