Date: Fri, 24 Jun 94 04:30:34 PDT From: Ham-Digital Mailing List and Newsgroup Errors-To: Ham-Digital-Errors@UCSD.Edu Reply-To: Ham-Digital@UCSD.Edu Precedence: Bulk Subject: Ham-Digital Digest V94 #206 To: Ham-Digital Ham-Digital Digest Fri, 24 Jun 94 Volume 94 : Issue 206 Today's Topics: new HAMCOM interface with optical isolation PACTOR FEC Frame PC-PAKRATT II GMT default What's packet radio? Where current KA9Q TCP/IP Software? Wormholes 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-Digital Digest are available (by FTP only) from UCSD.Edu in directory "mailarchives/ham-digital". 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: Thu, 23 Jun 1994 15:08:48 GMT From: ihnp4.ucsd.edu!swrinde!howland.reston.ans.net!news.cac.psu.edu!news.pop.psu.edu!psuvax1!news.ecn.bgu.edu!feenix.metronet.com!copeland@network.ucsd.edu Subject: new HAMCOM interface with optical isolation To: ham-digital@ucsd.edu Here are two opto circuit I've been playing with for HAMCOM/JVFAX. They virtually eliminate all computer induced rfi. I've been using a five foot serial cable and twenty foot audio cable with this circuit and the results are truly remarkable with JVFAX. I've used the first circuit successfully, but recommend using the second. The first can be built with common Radio Shack parts. The second requires a little more uncommon LM358 and TIL181. The Radio Shack opto RECEIVER is only rated at 20v but used at 24v and could eventually burn out. It also may introduced problems since the +9v is not regulated and induces error into the reference op amp output ... even though it seems to work well. Perhaps some engineers out there may have some advice. =============================================================================== +9v |-------- +9V ________ DTR 9 volt batt. --------- | 1uf | | ----- === | | | | [ ] 1K [ ] 2.2K |-------- | |________DSR GND |C | +9v ___ |/ - C | \ / /\/ | .1 uF |\ | ----- |\-> A >------| |--*-----------------------|- \ |A | | |741 \______| | | | / --------RTS | --------|+ / | | |/ | [ ] 100K [ ] 100K | | | GND *--------------* | | +9V | |\ | | -----|- \ | | |741 \___| +4.5 REFERENCE 100K [ ] | / |-----------|+ / 100K [ ] |/ | | GND =============================================================================== INFARED EMITTER INFARED DETECTOR (clear) (dark) ---------- ---------- | | | | | |__ | | | |__ | | | | | | | | | | | -- | | | -- | | | | | | | | | | ---------- ---------- | | | | | | These are available at Radio Shack as a pair for $1.99 (#276-142). This shows which is the Anode and which is the Cathode, not clear on the package. The LED and DETECTOR must be positioned right up against each other and exactly aligned to get maximum light transfer. The sides with the little lense like dots must be placed together. =============================================================================== I'd recommend this second circuit for more stability and possibly accuracy. RS232 connector size ----> 25 9 +9v -- -- | o +9V ----o DTR 20 / SPST SWITCH | | o SW1 | | | R1 [ ] 1K R2 [ ] 2.2K 9V *-------- | | BATTERY | | | |----o DSR 6 --------- --- C1 |1 TIL181 |5 ----- --- 1UF ....................... | | . |C U2 |C . * ------- . ___ |/ - . | . \ / /\/ | . GND . ----- |\-> . +9v . |A |A . | ....................... AUDIO 100 nF 6|\ |8 |2 |4 o------| |--*------------|- \ | | | | U1 \_7____| ----o RTS 4 | 5| / | ----|+ / LM358 2|\ | | |/ |4 ---|- \ R3 [ ] R4 [ ] | | | U1 \_1___ (not used) GND 100K | 100K| | | 3| / o-----------*-------*--------*------------*---|+ / LM358 | |/ GND =============================================================================== | ** NOTE** | | After constructing, measure LM358 pin 7 with no audio on the input. | | It should be high (~8v), if it is low (~0v) it will drain the battery | | in only 20 hours or less. | | | | To correct this: Disconnect R1 from +9v and reconnect to U1 pin 7. | | Disconnect U1 pin 2 and reconnect to GND. | | | =============================================================================== The LM358 is a single supply opamp and can be substituted with the LM2904, LM158, or LM258. (The dual supply 741 can not be used as a substitute.) The opto isolator IC can be substitued for many other types. The 4N35 has been tested successfully. The discrete infared emitter/detector from Radio Shack has been tested successfully. I tried to use a darlington opto (TIL113), but couldn't get it to work. A darlington opto circuit would only require 1.5ma average. That would make battery life about 133 hours. Maybe I'll try again later. =============================================================================== MORE NOTES: The 9v battery could be substitued with a 9 or 12 vdc adapter. However I've found the clearest pictures occur when both the radio and HAMCOM are running off batteries ... at 6am 8). A 9v battery should last about 50 hours while audio is present (assuming 200ma hours for a battery). If no audio is present the battery will last 400 hours. The battery life could be a problem for people who leave HAMCOM running all night using the timed FAX option. Battery would only last a week. If you have any advice or knowledge that could improve this, please let me know. copeland@metronet.com -- ---------------------------------------------------------------------- | copeland@metronet.com | ---------------------------------------------------------------------- -- ---------------------------------------------------------------------- | copeland@metronet.com | ---------------------------------------------------------------------- ------------------------------ Date: Thu, 23 Jun 1994 08:00:49 GMT From: ihnp4.ucsd.edu!mvb.saic.com!eskimo!rdonnell@network.ucsd.edu Subject: PACTOR FEC Frame To: ham-digital@ucsd.edu Rick Whiting (Rick_Whiting@ATK.COM) wrote: : There you have it, TOR fans! The PacTOR FEC frame revealed (assuming, of : course, that you've done your homework and know how the ARQ frame is : constructed). Remember, you read it first right here on the "ham digital" : newsgroup. Actually, I think I saw it in QEX a couple of years ago, when the protocol was first presented... 73 -- --------------------------------------------------------------------------- Bob Donnell, kd7nm bob@ethanac.kd7nm.ampr.org rdonnell@eskimo.com --------------------------------------------------------------------------- ------------------------------ Date: Thu, 23 Jun 1994 08:06:40 GMT From: ihnp4.ucsd.edu!mvb.saic.com!eskimo!rdonnell@network.ucsd.edu Subject: PC-PAKRATT II GMT default To: ham-digital@ucsd.edu Brian M. Perkin (bmp@cup.hp.com) wrote: : tmedin@che2.che.umn.edu wrote: : : does anyone out there know how to change the zulu time offset in this : : software? i purchased my software from someone in the Pacific time zone, : : with a used PK-232. it now has a 7 hour offset, i would like a 5 or 6 hour : : off set (CDT or CST). : : tom medin, N0UFM : : internet: tmedin@che2.che.umn.edu : This is documented in the manual for the software. : Check your autoexec.bat for a set command that sets : the variable "TZ". : Brian Another aspect of the TZ environment variable is that with most versions of DOS it will not take effect unless it is defined ahead of the path and/or prompt statements in your autoexec.bat file. What you want to do specificly is add a line near the beginning of your autoexec.bat file that says: SET TZ=CST6CDT When PC-Pakratt II finds this environment variable and the date your computer is set for, it automagicly determines if the 'daylight time' correction is needed instead of the 'standard time' correction. 73 -- --------------------------------------------------------------------------- Bob Donnell, kd7nm bob@ethanac.kd7nm.ampr.org rdonnell@eskimo.com --------------------------------------------------------------------------- ------------------------------ Date: 23 Jun 94 15:50:32 GMT From: news-mail-gateway@ucsd.edu Subject: What's packet radio? To: ham-digital@ucsd.edu >What's packet radio and how does it work? Does it let you connect to the >internet? Is it expensive? sounds like you might need more of a backgroud.... for starters call the American Radio Relay League at 800-32-new-ham and ask for the prospective ham package. 2nd look at a publication called "Now You're Talking" produced by the ARRL and available at places like Radio Shack -- this will cover some of the basics. 3rd look at a video tape produced by the guys at CQ Magazine called "Getting Started in Packet Radio" (if available). if you want protocol details there are several documents that get into the meaning of the bits and all that. there are content restrictions for amateur radio. so the answer is "no, packet radio doesn't let you connect to the internet at this time". Expensive is relative. if you have a computer and the right software then you can have a cheap dumb modem. if you want "serial device independance" where you can use any RS-232 serial device with the packet station, then you are looking for a terminal node controller... that should get you started... bill wb9ivr ------------------------------ Date: Thu, 23 Jun 1994 08:09:13 GMT From: ihnp4.ucsd.edu!mvb.saic.com!eskimo!rdonnell@network.ucsd.edu Subject: Where current KA9Q TCP/IP Software? To: ham-digital@ucsd.edu Eric Struble (eric@terrapin.rose.hp.com) wrote: : I know this is probily a FAQ but I am looking for the most current revision : of the KA9Q TCP/IP NOS Software. O figured it would be on oakland but I : couldn't find any there.... : Thanks in advance.... : Eric Take a look on ftp.ucsd.edu. Note that this is a different system at ucsd than the old 'ucsd.edu'. 73 -- --------------------------------------------------------------------------- Bob Donnell, kd7nm bob@ethanac.kd7nm.ampr.org rdonnell@eskimo.com --------------------------------------------------------------------------- ------------------------------ Date: 23 Jun 1994 17:12:29 GMT From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!news.cac.psu.edu!news.pop.psu.edu!psuvax1!news.cc.swarthmore.edu!netnews.upenn.edu!gopher.cs.uofs.edu!triangle.cs.uofs.edu!bill@network.ucsd. Subject: Wormholes To: ham-digital@ucsd.edu I seem to remember a while back some talk about using the INTERNET to provide wormholes to remote places. I even seem to recal that this capability was built into at least one version of NOS. Can anyone tell me where I can find out about this?? Are there any exotic places offering NETROM Nodes across the INTERNET?? Sure would impress the local ham community if I started running NETROM on my NOS box and had some european or australian Nodes in the table that were actually reachable. Any information would be greatly appreciated. bill KB3YV -- Bill Gunshannon | de-moc-ra-cy (di mok' ra see) n. Three wolves bill@cs.uofs.edu | and a sheep voting on what's for dinner. University of Scranton | Scranton, Pennsylvania | #include ------------------------------ End of Ham-Digital Digest V94 #206 ******************************