Date: Sun, 20 Mar 94 04:30:26 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 #67 To: Ham-Homebrew Ham-Homebrew Digest Sun, 20 Mar 94 Volume 94 : Issue 67 Today's Topics: Circuit simulation software for teaching Packet on old Military Radios (2 msgs) Parasitic oscillations, help! QSKing an AMP Small correction to XFILTER.BAS posted yesterday TX Amp for 20 mtrs QRP rigs. Whats the loss across a BNC to PL259 ? 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: 18 Mar 1994 15:32:58 -0500 From: ihnp4.ucsd.edu!usc!math.ohio-state.edu!magnus.acs.ohio-state.edu!mail-news-gateway@network.ucsd.edu Subject: Circuit simulation software for teaching To: ham-homebrew@ucsd.edu I'm conducting a survey about the use of computer programs for digital and analog circuit simulation in ee curricula. I'd like to know what software is being used at other universities, what platforms it's run on, what level (undergraduate/graduate) students are using it, and what problems other ee departments have had making this kind of software available for instructors and students. In particular, I'd like to know if there are fairly simple simulation packages (say 20-50 gates or components) that will run under UNIX or X-windows, or if there are DOS/Windows simulators that will run on a '286. Here at the Ohio State University we've experimented with several approaches, but none of them has been entirely satisfactory. There are some very sophisticated packages available for our UNIX/X-windows workstations that are suitable for the graduate level courses and research, but haven't proved satisfactory for the sophomore level courses. They have a lot of features that the beginning students just don't need. There are simpler packages available for DOS, but we can't run them on the UNIX workstations (there is a DOS/Windows emulation package, but it emulates a 286, and the simulator requires a 386.) We are reluctant to buy a lot of PCs, as the experience of other departments in the university indicates that PC networks are harder to maintain than the present network of UNIX workstations. -- Steve Brown, N8HFI sbbrown@magnus.acs.ohio-state.edu Chief Engineer, The Ohio State University Radio Observatory ("Big Ear") ------------------------------ Date: Tue, 15 Mar 94 02:06:21 GMT From: ihnp4.ucsd.edu!usc!cs.utexas.edu!utnut!nott!cunews!revcan!rubicon!pilate!dave@network.ucsd.edu Subject: Packet on old Military Radios To: ham-homebrew@ucsd.edu Has anybody out there ever connected a TNC to a PRC-77 (manpack) or RT-524 (veh mounted) VHF Military radio. I have to do just this and would really appreciate some advice. I understand the interface is nu as Mil-Spec as one would think. Thanks DAve -- Dave Mercer VE3XMJ | If Voting could change the system work: mercer@dgs.dnd.ca | it would be illegal home: dave@pilate.rubicon.org | -----BEGIN PGP PUBLIC KEY BLOCK----- Version: 2.3a mQCNAiw7jJkAAAEEALpAIvULlA/xvrzuR30NcLZE0HCHyGm5QR4ej8xM6k3AcH3T Q3NkgV2FK5f8t/fBAhO1+ffa5K7F10B4hPqKkAASNlk1PIx9ty5oUgxAlZnfya4V ScNIx0x2h2f3roRjiZLfNYM2zkm26sZhFQjVJxyNnluJq/xVb45/LyY+p9flAAUR tCBEYXZpZCBNZXJjZXIgPG1lcmNlckBuY3MuZG5kLmNhPg== =0azF -----END PGP PUBLIC KEY BLOCK----- ------------------------------ Date: Sat, 19 Mar 94 18:39:00 -0800 From: ihnp4.ucsd.edu!swrinde!sgiblab!wetware!kaiwan.com!ledge!bob.albert@network.ucsd.edu Subject: Packet on old Military Radios To: ham-homebrew@ucsd.edu The only problem I can see about using old gear on packet is the switching time. You will have to make sure the delay is long enough to allow the rig to change over to transmit from receive. Also, it may take a fair amount of current in the PTT line; if so you will have to add a buffer. 73 DE K6DDX ------------------------------ Date: Sat, 19 Mar 1994 18:22:39 GMT From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!newsserver.jvnc.net!raffles.technet.sg!ntuix!ntuvax.ntu.ac.sg!asirene@network.ucsd.edu Subject: Parasitic oscillations, help! To: ham-homebrew@ucsd.edu Hi, I am building a Ramsey kit QAMP-20, TX Amp with 20 watts output on 20 meters based on MOSFETS and I think I am experiencing parasitic oscillations at VHF, especially once the MOSFET gets hot. Why does this take place only when its hot? When its cool, say the first 20 seconds of keying, it seems ok but once the MOSFET gets hot, there goes the oscillations. Any ideas how I can fix this? I am redesigning the PCB with my own layout, is this advisable? The original board is single sided but I am not sure if their layout is well considered. The oscillations further cause the T-R relay to go beserk, understandably so. I am not too familiar with MOSFET design so I don't know what to do exactly. Will appreciate any advice. 73, Daniel ------------------------------ Date: Fri, 18 Mar 1994 20:02:00 GMT From: ihnp4.ucsd.edu!agate!usenet.ins.cwru.edu!eff!news.kei.com!yeshua.marcam.com!zip.eecs.umich.edu!panix!news.columbia.edu!psinntp!psinntp!psinntp!relay1!ecdcsvr!klf@network.ucsd.edu Subject: QSKing an AMP To: ham-homebrew@ucsd.edu Hi all, I hv a Heath SB1000 (Ameritron AL80A), that I wud like to add QSK to. ALl the QSK kits are a bit expensive for my taste, but I was wondering. Is it just the speed of the internal relay that keeps this thing from being QSK? Afterreading Richard Measure's (SP?) article in QST, if I just replace the internal relay with a high speed vacum relay (Jennings) will I be able to run it in QSK or are there other restraints. Tnks for any help you can give. DE KA3PLS ------------------------------ Date: Sat, 19 Mar 1994 04:36:42 GMT From: ihnp4.ucsd.edu!agate!usenet.ins.cwru.edu!nshore!seastar!jjw@network.ucsd.edu Subject: Small correction to XFILTER.BAS posted yesterday To: ham-homebrew@ucsd.edu Due to an un-corrected type in the original QST article, my crystal filter design program will result in incorrect values in one case. Change line 1020 to read as follows: 1020 DATA .7654,.8409,.5412,.8409,0,0,0,0,0,0,0 and this should correct the problem. Many thanks for those who pointed this out. -- While (its_not_working()) John Welch, N9JZW mess_with_it(); jjw@seastar.org ------------------------------ Date: 20 Mar 94 04:08:17 GMT From: dog.ee.lbl.gov!ihnp4.ucsd.edu!news.cerf.net!coyote.rain.org!coyote!leigh@ucbvax.berkeley.edu Subject: TX Amp for 20 mtrs QRP rigs. To: ham-homebrew@ucsd.edu asirene@ntuvax.ntu.ac.sg writes: >Hi, > Need recommendation for a small TX amp kit which takes about 4 watts output from my QRP rig and puts out 20-30 watts with >built in T-R switching (preferably solid-state T-R) and runs off 12-13.8v DC power supply. Must be small so I can fit it into my >existing rig's casing. Should be something similar to the QAMP-20 from Ramsey Hobby kits. BTW, this is for 20 meters. Tks. >73, >Daniel Daniel, if you stumble upon a small CB ampflier, you might try using it with your 20 meter QRP rig. Many of these amps are very broad banded, if sometimes somwhat dirty. I know of a local ham who sometimes steps up his 5 watt Ten Tec rig to about 50 watts on 40 meters, using a CB amp. --Leigh/KM6JE. ------------------------------ Date: 18 Mar 1994 14:34:20 -0600 From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!gatech!udel!news.sprintlink.net!bga.com!bga.com!nobody@network.ucsd.edu Subject: Whats the loss across a BNC to PL259 ? To: ham-homebrew@ucsd.edu Not a very scientific survey, but I have noticed that while adapters with BNC male and UHF female are ok, the ones that have BNC female and UHF male are create horrible SWR on my power meter. Has anyone else seen this? milton -- Milton Miller KB5TKF miltonm@bga.com ------------------------------ Date: Fri, 18 Mar 94 17:58:48 GMT From: mnemosyne.cs.du.edu!nyx10!tkell@uunet.uu.net To: ham-homebrew@ucsd.edu References <2m8nc6$m25@search01.news.aol.com>, , <763936883snz@gqrp.demon.co.uk> Subject : Re: QRP Designs George Dobbs - I got your address and tried to send you mail but the Postmaster says that it cannot find your address. Do you know your numeric address?? Could you please let me know so I can email to you? Thank you Ted Kell@lark.jsc.nasa.gov (kell@128.157.53.88) KC5CUW ------------------------------ End of Ham-Homebrew Digest V94 #67 ****************************** ******************************