Re: [PEDA] Systematically find unwanted antennas
At 11:45 AM 5/31/2002 -0700, Brad Velander wrote: John, my personal thoughts on the spreadsheet method was that it would only work in the limited case where the track was only connected at one end. In my past I have found a great deal of stubs where this method wouldn't work because there were actually two tracks connected at both ends to tracks atop one another or just slightly misaligned atop each other. If the data is prefiltered to remove the extra track that is fully coincident, the remaining overlapping track will be detected Note that misalignment implies lack of endpoint coincidence (Two identical tracks, however, would cause each track to be considered connected, which is why eliminating the redundant track first would be necessary.) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] Systematically find unwanted antennas
Hi Dennis, No, it isn't bad. It is absolutely essential to do visual scans of a PCB layout. The idea of a system for eliminating antennas is to catch anything one might have missed on inspection. Remember when all PCB designs were done without computers? All checking was visual. One major advantage of CAD is the systematic elimination of errors. Yours truly, John W. Childers - Original Message - From: Dennis Saputelli [EMAIL PROTECTED] To: Protel EDA Forum [EMAIL PROTECTED] Sent: Friday, May 31, 2002 11:51 AM Subject: Re: [PEDA] Systematically find unwanted antennas is the bd really too much to do a visual scan? you may want see other stuff you could clean up while you at it Dennis Saputelli * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] Systematically find unwanted antennas
Hi Brad, Right. But these are very easy to spot visually. The reason for a systematic approach is to find anything one might have missed on visual inspection. I find the antenna problem a very annoying problem with Protel and similarly (going back some years) PCAD and Tango. The genesis of the antennas is the approach of not deleting old junk traces from an update. As we talked about on the sci.electronics.cad newsgroup, this approach might be better than Pads or Cadstar, where the routes can not exist without connectivity. But the good side of the Pads and Cadstar approach is that you never get antennas unless you deliberately put them in by some work-around technique. Yours truly, John W. Childers - Original Message - From: Brad Velander [EMAIL PROTECTED] To: 'Protel EDA Forum' [EMAIL PROTECTED] Sent: Friday, May 31, 2002 12:45 PM Subject: Re: [PEDA] Systematically find unwanted antennas John, my personal thoughts on the spreadsheet method was that it would only work in the limited case where the track was only connected at one end. In my past I have found a great deal of stubs where this method wouldn't work because there were actually two tracks connected at both ends to tracks atop one another or just slightly misaligned atop each other. Sincerely, Brad Velander. Lead PCB Designer Norsat International Inc. Microwave Products Tel (604) 292-9089 (direct line) Fax (604) 292-9010 email: [EMAIL PROTECTED] http://www.norsat.com Visit us at Booth 2G2-09 at CommunicAsia 2002 in Singapore June 18-21. -Original Message- From: John W. Childers [mailto:[EMAIL PROTECTED]] Sent: Friday, May 31, 2002 9:59 AM To: Protel EDA Forum Subject: Re: [PEDA] Systematically find unwanted antennas From: Abd ulRahman Lomax [EMAIL PROTECTED] Most stubs can be classified into two kinds: stubs which terminate at a pad and stubs which do not. The latter could fairly easily be found by analyzing spreadsheet data from a PCB; essentially one would be looking for a track which has an endpoint which does not coincide with any other endpoint on the same layer, nor does it coincide with a via or pad. How would one generate a useful spreadsheet for this purpose? Thanks John W. Childers * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] Systematically find unwanted antennas
From: Drew [EMAIL PROTECTED] There is at least one layout package I know of that will report dangling lines and their x:y coordinates. Also, I have been told that running the database through Specctra will remove dangling lines. Though I have never witnessed the process, it might be worth looking into. From: Abd ulRahman Lomax [EMAIL PROTECTED] Some stubs might be eliminated by the autorouter; autorouter intelligence does encompass most if not all of what is needed to find stubs. I haven't tried it, but the autorouter might already eliminate some stubs, assuming that they are not locked. It seems to me that it once did. The trouble with using an autorouter, Specctra or Protel, to remove antennas is that in an update to a design, I wanted to preserve the existing routing. I used the Protel autorouter after removing as many junk traces as I could find. But I locked the exitsting traces, preventing the autorouter from going wild on the board. I had spent many hours on the previous revision cleaning up acute angles, of which the autorouter had generated thousands. I didn't want to go through that again. Thus, the autorouter could not clean up atnennas. (It also made dual traces, over but not exactly the same path as the locked ones, instead of using portions of the locked traces to connect to. But these were easy to find by inspection. In fact, it was searching for these redundant traces that revealed the antennas.) From: Ian Capps [EMAIL PROTECTED] I've only seen that capability in some of the gerber softwares. The old Lavenir View2001 does an unterminated trace check but Camtastic doesn't seem to have the ability. From: Bob Jones [EMAIL PROTECTED] I'm not sure about Camtastic but my CAM350 software will check for unwanted antennas. Does anyone know of any additional Gerber view software that checks for this besides Lavenir View2001 and CAM350? Thanks to all for your input, John W. Childers * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] Systematically find unwanted antennas
John, my personal thoughts on the spreadsheet method was that it would only work in the limited case where the track was only connected at one end. In my past I have found a great deal of stubs where this method wouldn't work because there were actually two tracks connected at both ends to tracks atop one another or just slightly misaligned atop each other. Sincerely, Brad Velander. Lead PCB Designer Norsat International Inc. Microwave Products Tel (604) 292-9089 (direct line) Fax (604) 292-9010 email: [EMAIL PROTECTED] http://www.norsat.com Visit us at Booth 2G2-09 at CommunicAsia 2002 in Singapore June 18-21. -Original Message- From: John W. Childers [mailto:[EMAIL PROTECTED]] Sent: Friday, May 31, 2002 9:59 AM To: Protel EDA Forum Subject: Re: [PEDA] Systematically find unwanted antennas From: Abd ulRahman Lomax [EMAIL PROTECTED] Most stubs can be classified into two kinds: stubs which terminate at a pad and stubs which do not. The latter could fairly easily be found by analyzing spreadsheet data from a PCB; essentially one would be looking for a track which has an endpoint which does not coincide with any other endpoint on the same layer, nor does it coincide with a via or pad. How would one generate a useful spreadsheet for this purpose? Thanks John W. Childers * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
[PEDA] Systematically find unwanted antennas
Re: [PEDA] Systematically find unwanted antennas
At 11:07 PM 5/28/2002 -0600, John W. Childers wrote: On a revision of a board, unwanted antennas can remain and must be found and removed. These are tracks that branch out from a net, but don't terminate on a pad, and can generate noise as electromagnetic waves, much like an antenna on a radio. Other than visual search, is there any systematic way to find them? Most stubs can be classified into two kinds: stubs which terminate at a pad and stubs which do not. The latter could fairly easily be found by analyzing spreadsheet data from a PCB; essentially one would be looking for a track which has an endpoint which does not coincide with any other endpoint on the same layer, nor does it coincide with a via or pad. Easy does not mean quick unless the utility has already been written As to stubs which terminate in a pad, a little more analysis would be necessary, but not so much as to become really difficult. However, there are certain kinds of stubs beyond this. For example, if a track connects at one end to a pad and then returns to that pad without connecting anywhere else, this would be a stub as well. Still, it would not be impossible to analyze a database to find stubs. Either Protel will add the tool at some time or a user will write a utility -- it does not have to be a server, though a server would be more convenient -- which would find and flag stubs. Some stubs might be eliminated by the autorouter; autorouter intelligence does encompass most if not all of what is needed to find stubs. I haven't tried it, but the autorouter might already eliminate some stubs, assuming that they are not locked. It seems to me that it once did. Note that connections made at other than pad or via or track endpoint center could make it more difficult to identify stubs And fills and arcs would add more complications * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] Systematically find unwanted antennas
I'm not sure about Camtastic but my CAM350 software will check for unwanted antennas. Sorry not much help here. - Original Message - From: John W. Childers [EMAIL PROTECTED] To: Protel EDA Forum [EMAIL PROTECTED] Sent: Wednesday, May 29, 2002 1:07 AM Subject: [PEDA] Systematically find unwanted antennas On a revision of a board, unwanted antennas can remain and must be found and removed. These are tracks that branch out from a net, but don't terminate on a pad, and can generate noise as electromagnetic waves, much like an antenna on a radio. Other than visual search, is there any systematic way to find them? John W. Childers * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] Systematically find unwanted antennas
I've only seen that capability in some of the gerber softwares. The old Lavenir View2001 does an unterminated trace check but Camtastic doesn't seem to have the ability. Ian Capps - Original Message - From: John W. Childers [EMAIL PROTECTED] To: Protel EDA Forum [EMAIL PROTECTED] Sent: Wednesday, May 29, 2002 3:07 PM Subject: [PEDA] Systematically find unwanted antennas On a revision of a board, unwanted antennas can remain and must be found and removed. These are tracks that branch out from a net, but don't terminate on a pad, and can generate noise as electromagnetic waves, much like an antenna on a radio. Other than visual search, is there any systematic way to find them? John W. Childers * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Re: [PEDA] Systematically find unwanted antennas
Hello, There is at least one layout package I know of that will report dangling lines and their x:y coordinates. Also, I have been told that running the database through Specctra will remove dangling lines. Though I have never witnessed the process, it might be worth looking into. Cheers! Drew - Original Message - From: Ian Capps [EMAIL PROTECTED] To: Protel EDA Forum [EMAIL PROTECTED] Sent: Thursday, May 30, 2002 4:31 PM Subject: Re: [PEDA] Systematically find unwanted antennas I've only seen that capability in some of the gerber softwares. The old Lavenir View2001 does an unterminated trace check but Camtastic doesn't seem to have the ability. Ian Capps - Original Message - From: John W. Childers [EMAIL PROTECTED] To: Protel EDA Forum [EMAIL PROTECTED] Sent: Wednesday, May 29, 2002 3:07 PM Subject: [PEDA] Systematically find unwanted antennas On a revision of a board, unwanted antennas can remain and must be found and removed. These are tracks that branch out from a net, but don't terminate on a pad, and can generate noise as electromagnetic waves, much like an antenna on a radio. Other than visual search, is there any systematic way to find them? John W. Childers * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/proteledaforum@techservinc.com * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
