Homebrew PCBs

Hi Ted,

I looked at the provided examples, and got the diameter/drill of the 
vias on it.  .048 /.032 drill.  seems to work.

Sounds like GND@1 is working for you.  A little confusing how they are 
placed/removed.  Hard to get rid of them after you've placed them! 
Finally did ripup followed by ratsnest and DRC commands.  I get a big X 
where the via was, and it finally goes away.  But all are fine now after 
being replaced.  DRC is good.

What else should I play with after I pretty it up a bit?

Alan  KM6VV


kilocycles wrote:
> Alan,
> I just tried the new part in place of the old one.  Originally, when I
> designed the symbol for it (it's an SBL-1 mixer), I just used the
> standard "wagon wheel" for the symbol for it, the TUF-1, ADE-1 and a
> homebrew version of the SBL-1.  Then, I realized when doing the first
> board, I had no convenient way to connect the external grounds and the
> two IF pins together (doh!).  I was trying to force wiring on the
> board view, and I didn't care for that much.
> 
> I redesigned a rectangular symbol with 4 pins on each side, and drew
> the wagon wheel mixer symbol inside it at .0125" grid resolution, and
> added the text to it.  Then I switched back to .1" resolution to make
> sure the pins would connect on the schematic.  I renamed the pins fro
> P$1 etc. to (in order, as the are one the actual device) RF, GND@1,
> IF@1, IF@2, GND@2, GND@3, GND@4 and LO for pin #8.  By the way, as
> expected, the "@1" doesn't show up on the symbol.  I set the pin to
> display the nam on the symbol only, and it just shows RF GND IF IF 
> and then GND GND GND LO coming back up the other side.
> 
> I just added them to the schematic of the product detector/audio
> schematic I'm working on, and it looks good on the schematic and
> board.  I disconnected the grounds temporarily to test that "auto net"
> thing with a supply.  I added a +12V supply and connected it to a
> transistor, and it didn't connect any of the grounds.  Then, I
> arbitrarily connected the +12V to the LO pin, and again, no
> auto-ground connection.  Maybe it will only do that if you have a part
> with a voltage supply defining one of the pins, like maybe on a 7812
> regulator, or something.  The regulators that are in the libraries
> don't do that, however.
> 
> I'm the wrong person to ask about vias.  I just made my first ones, on
> a board with some MMIC amplifier devices on the top ground plane side,
> along with the PA transistor at the other end of the board.  I *think*
> I'm doing it right; it added a via pad to the board, and I'll connect
> it through with a piece of wire.  Click on DRC, and then read the
> information regarding minimum drill for the Sizes and Restring tabs. 
> I don't completely understand it (it's Eagle!), but the Japanese
> tutorial suggested setting Restring at 40%.  I've had many situations
> where I had DRC errors for drill size, but I just ignore them, since I
> don't send the boards out for fabrication.  I don't even print the
> boards from the program, which could show the drill holes. I export
> them to .bmp files and edit them in Photoshop, adding text, making
> pilot holes, and use the "Threshold" control of Photoshop to ge a pure
> black and white image for printing.  It adds a considerable amount of
> time to do it that way, but that's the way I've always done it.  Until
> I figured out the "polygon gnd" thing, I even added fills using
> Photoshop.  
> 
> As to the specs, well, I pretty much ignore those as well.  After I've
> finished routing, I usually go back with the "Wrench" tool and
> redefine the traces to a wider trace, typically .032", as long as it
> still passes DRC.  I have seen specs for digital and mixed analog
> layouts on some sites, along with specs for signals crossing under
> other signals.  Obviously, signal trace widths and layer crossings are
> extremely critical at VHF and UHF, where the foil traces are inductors
> and capacitors.  I haven't seen any guidelines for HF, but I try to
> use common sense.  I tie the top ground plane to the bottom foil layer
> in several places, and I'm careful not to put a large trace across a
> critical section where capacitance through the 1/16" thickness of a
> board would be a problem.  For example, for those GHz-capable MMIC
> amplifiers mounted on the top layer, I left the foil side of the board
> blank underneath them and their circuitry to hopefully preclude VHF
> oscillations.
> 
> When I get the other mixer device symbols corrected, I can send you a
> copy of the small custom library they're in, if you want it.  I also
> have some toroids in there (bifilar and trifilar FT37-43, etc., and
> the Mouser 42IF123 IF can transformer that is used in several QRP rig
> designs.  Also a board-mounted RCA jack that I found at a local
> surplus house, to use for board-to-board connections with coax.
> 
> Ted