Hi All Just thought the list may be interested in knowing that the original PCB design by Adrian yo4hhp, for the main board all works fine on receive, not fully tested on TX, but does transmit OK. I've no high end test gear apart from a frequency counter, so you don't need a lot to get it working. A couple of small changes: 1) Inductor for BFO in series with 20 Mhz crystal, moved in series with just one variable capacitor, and inductor linked out. This was due to crystal not having enough movement for both USB & LSB. 2) Resistor in emitter of Q10 changed from 100 to 1K, otherwise Q10 overheats, possibly higher gain Q9/Q10 than in other builds, appears to have more than enough injection with 1K. I've attached a jpg, please note that this has been built with junk box bits apart from relays, & crystals so some components may not be the size intended :) Presently being controlled by PC using a Si570 via USB, and manual switches for LSB/USB, LPF. Receive audio very clear and tested on 3.5Mhz to 21Mhz, probably will need some screening around oscillator/IF Crystals. Next the controller. Cheers Alan VK2TVQ
Attachment:
MainBoard.jpg
Description: JPEG image
