This is one of the most difficult problem= s of PCB design I think. Making a 2-sided board that's not susceptible to E= MI means coupling the signal and return paths as well as the power paths. Y= ou want all significant currents to be in pairs so that the fields will can= cel. It helps to know which nodes in your circuit are susceptible to leakag= e from which other nodes and which kind of parasitics. You can identify sev= eral traces which hardly matter at all and abuse them to make room for the = important traces. And often you can also say that a parasitic will be helpf= ul at a certain node.

Using a uniform ground pla= ne with a 2-layer board means your traces may have to be MUCH longer and th= inner in order to get everything without jumpers. So a good question to ask= is, when do the parasitics of a long and/or thin trace outweigh the benefi= ts of a ground plane?

On Sunday, August 30, 2015 12:05 AM, "Stan Katz (stan DOT katz DOT hk AT gmail DOT com) = [via geda-help AT delorie DOT com]" <geda-help AT delorie DOT com> wrote:

First, I would like to mention that although I'm just a hobbyist, I lurk= on geda-user. I had been hoping and watching to see if a new PCB was going= to be released. I don't intend to understand the subtleties of the discuss= ions on geda-user, but I did note igor2's pcb-rnd fork was available. I did= n't think I would bother with it, since it wasn't official, but a problem c= ropped up, that made me change my mind. I had laid out a board in 1.9.1 whi= ch I compiled from source. When I tried to export the board to Postscript, = 1.9.1, PCB segfaulted. I switched to my distribution's PCB (20140316)= and that version also segfaulted. I decided that I should try pcb-rnd. Luc= ky for me, pcb-rnd didn't segfault. The trace colors were also nicely satur= ated, and easier on my old eyes. Give Igor2 one thumbs up from a rank amate= ur hobbyist....for what that's worth.

Now, to get down to my issue, I'm hoping that you can guide me towards a= book on producing excellent two layer boards for precision analog projects= . You pros probably reference books from Montrose, and Ott for your work. T= hat's great for 4 layers and up. These sources dismiss 2 layer board from t= he get go. The only advise directed towards 2 layer I could find was in a T= I journal. That advise, was....use one layer devoted entirely to ground, an= d then spend the rest of your life soldering jumpers on the component layer= . NO THANK YOU! Talented engineers back in the '60s and '70s were able to p= roduce quality two sided analog boards without jumpers. There must have bee= n a book, or two ( undoubtedly out of print now ) that guided designers bac= k then.

Can you help me out here?

Stan