Amateur radio operators are one of several groups who frequently design, build, modify and operate transmitters and recievers. As with other hobbies many document their work and share it via books, journals or magazines and via the internet. Some of these people are experts in their field - others, like me, have some formal training but much is self taught. You might look to publications and journals for designs and compare them to what you've been doing. American Radio Relay League is one organization and their publication is QST Magazine. I think the Radio Society of Great Britain's journal is QEX but I am not sure of that.