Date: Tue, 1 Mar 94 04:30:31 PST From: Ham-Homebrew Mailing List and Newsgroup Errors-To: Ham-Homebrew-Errors@UCSD.Edu Reply-To: Ham-Homebrew@UCSD.Edu Precedence: Bulk Subject: Ham-Homebrew Digest V94 #46 To: Ham-Homebrew Ham-Homebrew Digest Tue, 1 Mar 94 Volume 94 : Issue 46 Today's Topics: Forming inductors out of PCB traces question (2 msgs) linear amp?? (2 msgs) Looking for Motorola VHF power transistor sources Send Replies or notes for publication to: Send subscription requests to: Problems you can't solve otherwise to brian@ucsd.edu. Archives of past issues of the Ham-Homebrew Digest are available (by FTP only) from UCSD.Edu in directory "mailarchives/ham-homebrew". We trust that readers are intelligent enough to realize that all text herein consists of personal comments and does not represent the official policies or positions of any party. Your mileage may vary. So there. ---------------------------------------------------------------------- Date: Sun, 27 Feb 1994 09:50:05 GMT From: netcomsv!netcom.com!samiam@decwrl.dec.com Subject: Forming inductors out of PCB traces question To: ham-homebrew@ucsd.edu jdc3538@ultb.isc.rit.edu (J.D. Cronin) writes: >I once saw a RF modulator that used PC board traces for the inductor >in its tuned circuit; they were in a spiral pattern. Is this a good >method for forming inductors? Does capacitance to a ground plane >layer mess things up? I'd like to form a lowpass filter, so stray >capacitance to ground may not be a really bad thing.. >Also, how does one compute inductance? The ARRL Handbook gives a >formula for inductance of a coil where (coil length) > (.4 * coil diameter). >In this case we are working in a flat plane, so coil length = 0. >Also, coil diameter is not constant with a spiral inductor. >Any suggestions, ideas or references to books/articles are appreciated. >73...Jim >N2VNO Perhaps my own bias, but in IC layout there is much discussion of L calculation for traces. That's where I would look. Note that many PCB oriented books treat L of traces as strictly parasitic. [sam] -- Scott A. Moore [SAM] | OS/2: Better half an os than none at all ! samiam@netcom.com | SEGMENTATION: is great for bamboo. San Jose, CA USA | FUZZY LOGIC: is already, sadly, in wide use. 408-383-9154 | ------------------------------------------------------------------------ ------------------------------ Date: 27 Feb 94 16:24:41 GMT From: yuma!galen@purdue.edu Subject: Forming inductors out of PCB traces question To: ham-homebrew@ucsd.edu In article samiam@netcom.com (Scott Moore) writes: >jdc3538@ultb.isc.rit.edu (J.D. Cronin) writes: >>I once saw a RF modulator that used PC board traces for the inductor >>in its tuned circuit; they were in a spiral pattern. >>I'd like to form a lowpass filter, so stray >>capacitance to ground may not be a really bad thing.. >>Also, coil diameter is not constant with a spiral inductor. > >>Any suggestions, ideas or references to books/articles are appreciated. >>73...Jim >>N2VNO >Perhaps my own bias, but in IC layout there is much discussion of L calculation >for traces. That's where I would look. Note that many PCB oriented books >treat L of traces as strictly parasitic. > [sam] Yer readin' the wrong books. Try the ARRL UHF/Microwave Experimenters' Manual. Nice treatment of MICROSTRIP elements. If you want more theory, back up a chapter to the end of transmission media. They don't get into complex configurations like spirals, but there is a long list of references for further reading. galen, KF0YJ ------------------------------ Date: 27 Feb 1994 22:14:57 GMT From: ihnp4.ucsd.edu!swrinde!cs.utexas.edu!uwm.edu!csd4.csd.uwm.edu!jjessie@network.ucsd.edu Subject: linear amp?? To: ham-homebrew@ucsd.edu does anybody have any plans for a 30-150 (preferably 100) watt linear amp?? thanks, scott jessie ------------------------------ Date: 28 Feb 94 00:31:04 GMT From: yuma!galen@purdue.edu Subject: linear amp?? To: ham-homebrew@ucsd.edu In article <2kr611INN6sr@uwm.edu> jjessie@csd4.csd.uwm.edu (Joyce K Jessie) writes: >does anybody have any plans for a 30-150 (preferably 100) watt linear amp?? >scott jessie What Frequencies? Get a catalog from Communication Concepts Inc. 513-426-8600 They'll have kits, circuit boards, transistors, transformers.... ------------------------------ Date: 28 Feb 1994 00:04:18 GMT From: ihnp4.ucsd.edu!swrinde!cs.utexas.edu!bga.com!vern.bga.com!kbrune@network.ucsd.edu Subject: Looking for Motorola VHF power transistor sources To: ham-homebrew@ucsd.edu J.D. Cronin (jdc3538@ultb.isc.rit.edu) wrote: : I'm looking for some Motorola VHF power transistors (MRF240/A and : others). The only catalog I found them in is from a company that : is no longer in business. Any suggestions? I looked in the : mailorder list from ftp.cs.buffalo.edu, but nothing looked : promising. : 73...Jim : N2VNO Jim, Newark Electronics has it for $25 they have offices all over here is the Washington State # 1-800-321-8984....Ken WL7IR ------------------------------ End of Ham-Homebrew Digest V94 #46 ****************************** ******************************