Date: Tue, 8 Feb 94 04:30:47 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 #23 To: Ham-Homebrew Ham-Homebrew Digest Tue, 8 Feb 94 Volume 94 : Issue 23 Today's Topics: EXAR 2123 sources new radio communications mailing list T-368 transistorization 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: 7 Feb 94 19:01:59 GMT From: news-mail-gateway@ucsd.edu Subject: EXAR 2123 sources To: ham-homebrew@ucsd.edu Does anyone know where I can buy small quantities of the EXAR 2123? It's used on the MFJ 2400 baud TNC modem. Thanks, Bob bapplega@isd.csc.com ------------------------------ Date: Mon, 7 Feb 1994 21:59:41 GMT From: newshub.nosc.mil!news!martinb@network.ucsd.edu Subject: new radio communications mailing list To: ham-homebrew@ucsd.edu RADIO COMMUNICATIONS MAILING LIST We have started a mailing list for professionals in the field of radio communications. Relevant topics include antenna design, radio propagation, hardware design, software design, FCC rules, market trends, military requirements, and so forth. If you make your living from the radio communications field (or think you might in the future), then you are invited to subscribe. Hobby-related questions should remain with the rec.radio.amateur.* series of newsgroups. To subscribe, send a message to: martinb@cod.nosc.mil IF YOU HAVE ALREADY SUBSCRIBED BUT ARE NOT RECEIVING MESSAGES, THEN YOU MAY HAVE SENT YOUR MESSAGE TO THE WRONG ADDRESS! I have not received any messages that may have been sent to martin@cod.nosc.mil. If I receive your subscription message, I will reply with an informational message, and you will begin to receive RadioCommNet messages in your e-mail mailbox. Of course, you may unsubscribe at any time. Brett F. Martin Naval Command, Control, and Ocean Surveillance Center San Diego CA martinb@cod.nosc.mil ------------------------------ Date: Tue, 8 Feb 1994 06:07:57 GMT From: dog.ee.lbl.gov!agate!iat.holonet.net!rohrwerk@network.ucsd.edu Subject: T-368 transistorization To: ham-homebrew@ucsd.edu I got about 5 requests for more info on transistorizing the T-368 exciter as a VFO for ham projects. I've got a nice long reply for anybody who wants it by individual E-mail and/or snail mail. Let me know John Seboldt K0JD ------------------------------ Date: 6 Feb 1994 21:52:14 GMT From: koriel!newscast.West.Sun.COM!abyss.West.Sun.COM!pongo!myers@decwrl.dec.com To: ham-homebrew@ucsd.edu References <1994Jan28.013626.1@ntuvax.ntu.ac.sg>, <2ikeaeINN97u@abyss.West.Sun.COM>, <1994Feb3.202807.9673@arrl.org> Subject : Re: Antenna pre-amp design. Help! In article <1994Feb3.202807.9673@arrl.org> zlau@arrl.org (Zack Lau (KH6CP)) writes: >Dana Myers (myers@cypress.West.Sun.COM) wrote: > >: If you feel like working just a little, try using a broad-band grounded >: gate J310; you can get about the same gain and IP3 but a noise figure below >: 1dB. Use a small ferrite balun core with a turns ratio of 4:1 (16:1 Z ratio) >: on the output, use a 220 ohm bias resistor, go to town. I bought a stash >: of J310s for $.34/ea; the additional components would make the total cost >: similar to the MSA-1104 circuit, with a lower NF. > >Have they improved this device from the mid 70s? (J310) > >Amateur literature indicates that people would try >this for Gunnplexer and satellite preamps >before ending up with either an exotic bipolar >or dual gate MOSFET design that just came in with a >1 dB noise figure. Really low noise figures are >quite useful for IF amplifiers, particularly if the >reverse isolation is high. As I recall, the pre-amp was for HF-UHF; the J310 should do just fine in this service. Were people trying to use the J310 at GHz range, or were they trying to use them in IF amplifiers at VHF range? Interestingly enough, Dr. Rohde's article in the 1/94 QEX, on page 11, refers to the U310 (same die as J310) as the lowest noise FETs up to 500MHz. Also, Zack, the schematic on page 27 represents the MRF137 as a P-channel MOSFET. I'm sure the guys at Motorola would like to know this, since they think it is an N-channel FET :-) -- * Dana H. Myers KK6JQ, DoD 466 | Views expressed here are * * (310) 348-6043 | mine and do not necessarily * * Dana.Myers@West.Sun.Com | reflect those of my employer * * This Extra supports the abolition of the 13 and 20 WPM tests * ------------------------------ End of Ham-Homebrew Digest V94 #23 ****************************** ******************************