Thanks Satish, John and Arv.
I did not have the BPF connected at the time of experimenting. But it would probably lower the signal even more. So it's best to get a strong signal before I attempt modifying the BPF. Satish makes a very good point, there is a 0.2 V loss in the 1N4841 diodes of course. Why did I not think of that myself? I did pass the exam but it's been a while. ;)
I will try John's suggestion and crank up the signal a bit to around 0.6Vp-p. Will post here how it turned out.
Arv, I use small pieces of (leftover) copper clad board, about 2.5 x 4 cm in size, around 1 by 2 inch per module and simply solder the components on dead bug style. I cut some small squares and glue them on as solder-islands where needed. The modular approach is great because you can test them individually. When I get to the final I will need a slightly bigger board and when everything is finished I will put all small prints on a larger board. Maybe put some 12V, TX and RX rails on it and I will call it the motherboard as well.
