The KG4NJA VHF Digipeater
(Alias LARCND)

Pictures

Select each picture to see a larger view and accompanying text description.

2001.07.20	2001.07.20	2001.07.20
2001.07.20	2001.074.20	2001.07.20
2001.07.20	2001.07.20	2001.07.20

Acknowledgments

Many thanks go to Earl Moore (KR4MA) and many others of the District 7 Emergency Coordinators for donating the Yaesu FT-1500 radio and the Kantronics KPC-3 TNC. The power supply was donated by Jim Byrd (WB5POJ) and the original cabinet enclosure was provided by Nick Karangelen (W4LSG).

How do I setup a packet radio station?

To setup a packet radio station you will need the following items:

• A computer with a RS-232 serial communications connector.
• Software loaded on the computer for packet radio communications.
  • For Win95 OS and later, try the freeware program WinPack 6.7.
  • For DOS and Win3.1, try Paket61.zip courtesy of the QRZ.com website.
  • If you want to use a DOS NTS (National Traffic System) formatting program, try NTS12.EXE. This can be found at Simtel.net as NTS12.ZIP.

• A packet terminal node controller (TNC). There are many kinds available, perhaps one of the most common (and simple to use) is the Kantronics KPC-3. There are several other suitable products made by other manufacturers, including the MFJ-1270B, AEA PK-88, Baycom, etc.,
• A RS-232 cable to connect the computer RS-232 port to the TNC RS-232 port.
• A VHF FM radio with external connections for transmit audio, receive audio, and PTT (push to talk) switching.
• Suitable cables to connect the VHF radio to the TNC and accomplish the following:
  • Transmit audio (TNC (transmit audio output) -> VHF radio (transmit audio input).
  • Receive audio (VHF radio (receive audio output) -> TNC (receive audio input)).
  • Transmit control (TNC (PTT control) -> VHF radio (PTT control)).

• Suitable power sources for all the above.
• A suitable antenna for the purpose of reaching a local packet PBBS station or securing the services of a local digipeater to link to the same.
• Proper parameter settings in the TNC to allow simple packet communications. This requires some study of the user's manual for the appropriate TNC that is used.

  For "get on the air right now sake", I list the following parameters that I use with the Kantronics KPC-3 to help you get going. These were displayed with the KPC-3 "disp" or "display parameters" command:

  8BITCONV ON
  AX25L2V2 ON
  ABAUD    1200
  AUTOLF   ON
  AXDELAY  0
  AXHANG   0
  BEACON   EVERY 15 min
  BKONDEL  ON
  BTEXT    WB5POJ/KPC-3 (-1 PBBS) - Jim Byrd - jbyrd@members.vectec.org
  BUDLIST  OFF
  BUDCALLS NONE
  CANLINE  $18 (CTRL-X)
  CANPAC   $19 (CTRL-Y)
  CD       INTERNAL
  CHECK    0 (disabled)
  CMDTIME  1 (1 sec)
  CMSG     ON
  COMMAND  $03 (CTRL-C)
  CONLIST  OFF
  CONMODE  CONVERS
  CONOK    ON
  CPACTIME OFF
  CR       ON
  CRSUP    OFF
  CSTAMP   ON
  CTEXT    Hello - WB5POJ/KPC-3 - Jim Byrd - jbyrd@members.vectec.org
  CWID     EVERY 0 (disabled)
  CWIDTEXT DE *
  DAYTIME  11/21/01 08:26:37
  DAYTWEAK 8
  DAYSTR   mm/dd/yy hh:mm:ss
  DBLDISC  OFF
  DELETE   $08 (CTRL-H)
  DIGIPEAT ON
  DWAIT    0
  ECHO     OFF
  ESCAPE   OFF
  FLOW     ON
  FILTER   ON
  FRACK    4 (4 sec)
  FULLDUP  OFF
  HBAUD    1200
  HEADERLN ON
  HID      ON
  HTEXT    
  INTFACE  TERMINAL
  KNTIMER  15 min
  LEDS     ON
  LCOK     ON
  LCSTREAM ON
  LFADD    OFF
  LFSUP    OFF
  LLIST    OFF
  MONITOR  ON
  MALL     ON
  MAXFRAME 4
  MAXUSERS 10
  MBEACON  ON
  MCON     OFF
  MCOM     ON
  MRESP    ON
  MRPT     ON
  MSTAMP   ON
  MXMIT    ON
  MYCALL   WB5POJ
  MYALIAS  
  MYNODE   WB5POJ-7
  MYPBBS   WB5POJ-1
  MYREMOTE (you do not get to see this! hee hee)
  NDWILD   OFF
  NEWMODE  ON
  NOMODE   OFF
  NTEXT    
  NUCR     0
  NULF     0
  NUMNODES 0
  PACLEN   128
  PACTIME  AFTER 10 (1000 msec)
  PARITY   NONE
  PASS     $16 (CTRL-V)
  PASSALL  OFF
  PBBS     5
  PBFORWRD NONE  EVERY 0 (disabled)
  PBHEADER ON
  PBHOLD   ON
  PBKILLFW OFF
  PBLO     NEW VARIABLE
  PBPERSON OFF
  PBREVERS ON
  PERSIST  63 (25%)
  PID      OFF
  PTEXT    Hello from Jim Byrd's KPC-3 - leave a message.
  REDISPLA $12 (CTRL-R)
  RELINK   OFF
  RESPTIME 5 (500 msec)
  RETRY    5
  RING     ON
  RNRTIME  0 (disabled)
  RTEXT    (you do not get to see this! hee hee)
  SCREENL  0
  SENDPAC  $0D (CTRL-M)
  SLOTTIME 10 (100 msec)
  START    $11 (CTRL-Q)
  STATSHRT ON
  STOP     $13 (CTRL-S)
  STREAMSW $7C (|)
  STREAMCA OFF
  STREAMEV OFF
  SUPLIST  OFF
  SUPCALLS NONE
  SWP      17,17,108
  TRACE    OFF
  TRFLOW   OFF
  TRIES    0
  TXDELAY  30 (300 msec)
  TXFLOW   OFF
  UNPROTO  WB5POJ VIA LARCND
  USERS    1
  XFLOW    ON
  XMITOK   ON
  XOFF     $13 (CTRL-S)
  XON      $11 (CTRL-Q)
  

To understand the useage of all the parameters above there is several days of study involved. The preception that one must understand all the TNC parameters is one of the reasons why many shy away from packet radio. I do frequently refer to the user's manual to have a at least a minimal understanding about what the parameter definitions mean.

But quite frankly, if I can communicate with the other fellow and accomplish the needs of myself and the community I do not care what the parameters mean!.

A few of the parameters are more familiar and intuitive than others. Many of the items above are defaults (standard values after a reset command). If you get fully frustrated at this point I suggest the following:

• Power up the TNC, this causes a "reset" command to be performed.
• Start the packet software and configure the RS-232 serial port you are using (i.e. com1 or com2) for communications at "1200 bps", "N" (no parity), "8" (bits per byte), "1" (stop bit).
• Press the (carriage return) key to see a command prompt (i.e. "cmd:").
• Set the MYCALL parameter to your callsign (i.e. "MYCALL WB5POJ" ).
• For fun, attempt to list the TNC parameters (i.e. "disp" ).

If you have gotten this far, you are ready to begin basic packet communications. Don't worry, it only gets a little more complicated from here on.... If you are looking for used equipment, let me suggest the EHam Classifieds as a place to start.

How do I use the KG4NJA (LARCND) digipeater?

A little background information is required here. Packet radio operates much like pre-Internet telephone based BBS systems. The one can send messages to another station, chat in a conference, and listen to other traffic all on the same frequency. Most of the time you will want to have a packet radio address managed by a local Packet Bulletin Board System (PBBS). Your TNC is essentially a modem for use with radio communications.

The KG4NJA (alias LARCND) digipeater node is intended to operate as a digital relay station, much like the concept of a voice repeater, though the communications are not simultaneous two-way communications.

Packet PBBS systems are almost always located at someone's home and will generally have excellent antennas, but usually not much more than about 80 feet in height. As a result, the direct connection range is generally limited to 10 miles or less.

One of the best local PBBS sites is located at KR4MA. This automated packet station is a MSYS PBBS owned by Earl Moore. It is physically located in Yorktown Virginia, not far from the Yorktown Public Library on highway 17 in York County Virginia.

The first time I connected with the KR4MA PBBS I was asked in an automated dialogue if I wanted KR4MA to be my home PBBS. I agreed, and thus I provided my name, qth, and zip code during the first contact. The PBBS defined my packet address for me [wb5poj @ kr4ma.#tide.va.usa.noam] and that is where I connect to find if I have received messages. My own TNC has a mailbox capability, but since I do not keep it operational 24 hours per day it is best to designate a continuously operating local PBBS to receive and forward messages for you.

The KR4MA PBBS is within line of site of my best antenna therefore I routinely connect directly to the KR4MA PBBS by using the command:

c kr4ma

The KR4MA PBBS responds with several lines of introduction information, topical headers, then a command list.

Let's say for instance that I have moved out of the KR4MA PBBS range, my antenna is not working well, or I am running lower transmit power than usual and I still need to reach the KR4MA PBBS. I can utilize the KG4NJA digipeater (alias LARCND) to achieve a connection to KR4MA PBBS by using the "connect via" command.

Packet radio protocol allows KG4NJA to operate as a digipeater with an alias name to make the digipeater easier to remember and locate. The alias name for the KG4NJA site is LARCND (Langley Amateur Radio Club NoDe). This name was voluntarily picked in accordance with Virginia ARES digipeater naming standards.

You can connect directly to KG4NJA, but other than a "####Connected" message, there is no one there to answer you so a manual disconnect on your part is required.

If you wish to leave a message on the PBBS, you should connect to KG4NJA-1. At that time a dialogue will appear and you may leave a message according to the instructions. Remember however, the current configuration of the system will not forward your message to another PBBS. The receiver of the message will have to login into KG4NJA-1 to receive and reply to the message if desired. If you desire, message #6 may be read to learn on-air facts about the KG4NJA/LARCND digipeater.

To use the KG4NJA digipeater (alias LARCND) as a relay to connect with the KR4MA PBBS, use the following command sequence:

c kr4ma via larcnd

The KR4MA PBBS will respond, but a bit slower since the LARCND digipeater is relaying the communications between the KR4MA PBBS and myself (WB5POJ). Ideally the digipeater should allow one to connect up to 40 miles away from other stations without difficulty. And thus perhaps one can see the power of the digipeaters in extending packet radio communications range.

One might ask, "What other individual ground stations, PBBS stations, and dedicated nodes (like LARCND) are being heard by the KG4NJA digipeater?" To find out, connect directly to LARCND with the following command:

c larcnd

A connect text string and a short list of abbreviated commands will appear:

cmd:*** CONNECTED to LARCND [11/21/01 11:53:20]
###CONNECTED TO WILD NODE LARCND(KG4NJA) CHANNEL A
KG4NJA/LARCND - NASA Langley ARC - 10W @ 240Ft. - Hampton, VA
ENTER COMMAND: B,C,J,N, or Help ?

This is the short command menu. The "Help" reponse will describe the commands in more detail.

One of those commands "j", will list the last 20 or so individual ground and dedicated PBBS stations that have (j=just) been heard by the LARCND node. A time of day stamp is included. Initiating the "j" command:

j

Yields the identification of individual and PBBS stations:

WA8AHV     11/21/01 11:16:12
AF4CD-12   11/21/01 11:16:13
AF4CD-1    11/21/01 11:17:45
KF4QFH     11/21/01 11:17:47
W4ZA       11/21/01 11:29:15
WA8AHV-2   11/21/01 11:35:39
KF4LMN     11/21/01 11:36:54
KR4MA-2    11/21/01 11:37:36
KE4DV-7    11/21/01 11:41:11
KE4DV      11/21/01 11:43:05
KS4GC      11/21/01 11:43:51
KR4MA      11/21/01 11:49:06
WA8AHV-3   11/21/01 11:49:13
KE4PGU     11/21/01 11:49:23
WA8AHV-12  11/21/01 11:50:37
AF4CD-2    11/21/01 11:50:38
W4ZA-8     11/21/01 11:51:52
W4JJK      11/21/01 11:52:21
WB5POJ     11/21/01 11:55:17
ENTER COMMAND: B,C,J,N, or Help ?

To reveal the list of other dedicated digipeater nodes, use the "n" command to receive information about other dedicated nodes that can be used to hop to PBBS destinations that are much further over the horizon. Responding with the "n" commmand:

n

Yields identification of node stations:

OYSTER     (KF4HJW-9)  11/18/01 16:01:47
W4TLM-7*   (W4TLM)     11/18/01 22:41:22
POORND     (KD4BNQ-7)  11/19/01 05:45:14
GTNMND     (WB3FUM)    11/19/01 06:50:53
CARA       (K4VDN-5)   11/19/01 08:26:56
NVAHUB     (K4VDN-2)   11/19/01 09:29:19
WA4JR-7    (WA4JR)     11/19/01 10:49:59
KS4GC-7    (KS4GC)     11/19/01 12:10:29
METEST     (N4NSP-1)   11/19/01 20:21:29
BUCKND     (N4PGS-12)  11/20/01 02:27:34
NOMEND     (KF4LMN)    11/20/01 16:28:40
DTENND     (WT4RA)     11/20/01 20:31:03
TIDE       (KE4CVY)    11/21/01 10:11:20
AF4CD-7    (AF4CD)     11/21/01 11:14:28
KR4MA-7    (KR4MA)     11/21/01 11:47:44
WA8AHV-7   (WA8AHV)    11/21/01 11:55:55
ENTER COMMAND: B,C,J,N, or Help ?

To disconnect from the LARCND digipeater, use the "b" command for "bye". Responding with the "b" commmand:

b

Yields a disconnect message:

*** DISCONNECTED [11/21/01 11:59:06]
cmd:WB5POJ>LARCND/1 [11/21/01 11:59:06]: <>:

Where is the KG4NJA (LARCND) Digipeater Located?

• The KG4NJA digipeater is located on the IDRF gantry at the NASA Langley Research Center in Hampton Virginia.
• Here is a map position of the NLARC repeaters at the NASA Langley Research Center in Hampton Virginia.

Common SSID Usage for Packet

The following table of SSID identifiers was compiled from conversations with local hams.

(default) -0	(pbbs) -1	-2	-3	-4	-5	-6	digipeater -7	-8	-9	-10	-11	-12	-13	-14	-15	alias
	KG4NJA															LARCND

If you have more questions about how the digipeater operates, please contact Jim Byrd (WB5POJ) at 757.874.3104 for more details.

Packet Radio Resources

• An Introduction to Packet Radio by Larry Kenney, WB9LOZ.
• The Packet Radio Training Course by Joe Krigbaum K6NE.
• The Tucson Amateur Packet Radio Association.
• The PacketRadio page.
• The AC6V's Amateur Radio and DX Reference Guide.

Web page operations: James E. Byrd
Responsible NASA Official: Richard S. Eckman