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1994-11-13
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Date: Fri, 24 Jun 94 04:30:34 PDT
From: Ham-Digital Mailing List and Newsgroup <ham-digital@ucsd.edu>
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: <Ham-Digital@UCSD.Edu>
Send subscription requests to: <Ham-Digital-REQUEST@UCSD.Edu>
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 <std.disclaimer.h>
------------------------------
End of Ham-Digital Digest V94 #206
******************************