2.10 Multiple Computer Contesting

XXX This page is simply a copy without screen shots of the corresponding page in the N1MM Logger Classic manual XXX

It is possible to use N1MM logger in a multi-computer networking environment, either supporting the multi-operator contest categories or for special purposes for a single operator (continuous backup, two-computer SO2R, to separate the radio control and Internet access functions into two computers, ...). For this to work you need at least two networked computers, with a maximum of 16. These computers need to have network interface cards or wireless interfaces. The networking protocol used is TCP/IP. Each computer has its own separate copy of the database; this is not a client-server shared-database configuration. Nevertheless, the network needs a so-called "Master" station. The "Master" station is the one that sets the time, connects to packet/telnet, etc. The Master station is always station number 0, in the "Edit Station Computer Names" table.

1. Features


  • Maximum of 16 networked computers with one 'master' station (0-15)
  • Use of standard network interface cards (NIC's) and wireless interfaces
  • Dynamic naming or static IP addressing can be used for station identification
  • Connected computers can be on the same subnet, or distributed across a wide area to any internet-connected computer
  • Talk capability between networked stations
  • Automatic time synchronization
  • Pass frequency information between stations
  • DX Spots from Telnet or Packet
    • Distributed to all connected computers
    • The ability to send spotting commands from any station on the network
  • Error messages when a station can't be questioned/updated
  • The Info Window gives status information and extra options
  • The Config menu has a special Multi-User Tools menu
  • Auto resync when a station comes on-line

 Turning Off Networked-Computer Mode

NEVER turn off the networked-computer switch during a contest. This results in contacts being logged to the wrong station while the networked-computer switch is turned off. During testing, to simulate a network failure, kill the ethernet connection.

 CAUTION about Software Lockouts

The "Force Other Station to Stop Transmitting When I Transmit" and "Block my Tx Only if Other Stn Transmitting on Same Band&Mode (Multi-One)" menu items are software lockouts. They are subject to network latencies and cannot be guaranteed to prevent simultaneous transmitting. Because of network latencies, lost packets, network dropouts or network failures there could be short overlaps in transmissions, or even complete failure of the lockout. For protection against damage from simultaneous transmitting, and/or to be absolutely certain that contest rules forbidding simultaneous transmissions are obeyed at all times, you must use a dependable hardware lockout system. Do not depend on software lockouts to prevent equipment damage and do not expect software lockouts to give you an ironclad guarantee of compliance with contest rules!

2. Information


  • Connection status:
    • Green - Connected
    • Red - Not connected, but the other computer is being actively polled. Initially, when a computer is unable to reach another computer in the N1MM Logger network, the connection "ball" in the Info Window will turn red polling for the unreachable computer will continue for 3 minutes. . Users may experience delays or stuttering in this state. After 3 minutes, the polling will be automatically suspended, and the connection "ball" will turn blue. Since polling has been suspended, there will be no performance impact on users. When the unreachable computer comes back on-line, the computers will automatically reconnect, and the connection "ball" will turn green.
    • Blue - Not connected, but the other computer is not being polled. When the other computer becomes reachable, the connection will be automatically reestablished. Users will not experience delays or stuttering in this state.
    • Light red - Connection in progress or connection lost, the program will try to solve this situation. This is a transient state.
  • Station name
  • Pass frequency - clicking the pass frequency will send a message to the selected station. If the selected station is your own computer then the left VFO frequency will be changed to the current pass frequency.
  • Is he running or S&P
  • Who is the operator
  • Rate information
  • Run/pass frequency

2.1. Rules


The following 'smart' rules for run/pass frequency are implemented.

  • Running
    • I'm on & running
      • If the running check box is checked, always send to run frequency

  • Not running
    • I have a run frequency, but I'm chasing a multiplier
      • The run frequency holds for 1 min, then gets zeroed
    • I'm not running, and I have a pass frequency way up the band
      • The user will have to specify the pass frequency
    • Don't pass, my pass frequency is no good
      • I guess it is the operators responsibility to zero the pass frequency
      • Maybe a timer to remind if no QSOs on pass frequency for n minutes? (not yet implemented)
    • Don't pass, my CQ frequency is no good
      • Timer with no CQ's or QSOs on run frequency for 1 min? (not yet implemented)

2.2. Displaying Rules


Running - Show the run frequency

Not running - Show the pass frequency if non-zero, if no pass frequency then show last CQ frequency if non-zero.

3. Macro keys


Macro key substitution is supported by most programmable buttons in the program. For Multi-User mode there are a few specific macros which can be found on the Macros Chapter.

4. Features


  • Call stacking - Call stacking between computers, enter a callsign on a remote computers 'stack'
    • To indicate which station you want to stack for, right click on it's "cue-ball" in the info window, and select the option "Target for call stacking"
    • A maximum of one callsign can be stacked. If the stack is empty another one may be stacked
  • Prohibit transmitting
    • If another station is sending (single operator or multi-one) don't allow sending if another station is sending
    • If another station is sending (multi-two or multi-multi) don't allow sending on same band
    • See also the option in the Networked-Computer tools under Config: Force Other Station to Stop Transmitting When I Transmit

5. Where to Place the Database Files


Do not share the log on a server, place it locally on the hard disk of each station.

  • Sharing logs on a server will MOSTLY not work. Mostly is not good enough. You will think you are ok, but are not. I do not check for Networked-Computer temporary errors. The program was NOT designed nor tested for this
  • Having the log on every PC provides redundancy, which is important in an RF-filled environment
  • It will not perform as well. Local access is almost always faster.

There is no harm in using a server to aid in copying files. The mdb files are simply files. They may be moved around. It is best to close the program before moving them, as with any program writing to an open file.

6. Other Information


  • Deleting QSOs made by another station in a Networked-Computer situation is not allowed, and a warning message is shown. QSO's must be deleted on the station that made the QSO.
  • Station 0 sends all incoming spots to every station so the bandmaps are being filled. Use the Telnet window (not the Packet window) on the other computers in the network. If you send a message to the packet cluster from any station in the network it will be sent out to packet/telnet via computer 0. The received answer from the packet cluster will be send out on the network to all stations
  • The program should not be shutdown while initializing Networked-Computer mode, otherwise unpredictable situations could occur
  • You will be prompted for the operator call if it has not been entered (with Ctrl+O). A periodic warning message will be shown if no operator has been specified
  • After you have entered the operator call, you can go to Save Window Positions on the entry window's Tools menu and save the window setup for that particular operator. Thereafter, when that operator signs on again, the window setup will be adjusted to the operator's preference.
  • The CQ/pass frequencies will be requested at startup
  • When going through the possible contests you will see a "contest" DELETEDQS. This is not a contest but deleted QSOs will be moved here by the program. This can be useful after the contest.
  • Connection status is shown at the bottom of the info window
  • A connection is checked every 10 seconds
  • All connections are stopped/started when the database, the contest or the connection list is changed
  • Also Non-master stations are allowed to close telnet/packet ports
  • Time synchronization is only shown on the master station
  • Non-master stations in Windows Vista, 7 or 8 should be run using the "Run as Administrator" option in Windows, in order to allow the Master station to adjust the system time in the non-master stations so all computers have the same time
  • If you Mark or Store spots on a local machine, they will be Marked or Stored on all other machines
  • The station name prefixes telnet/packet commands that are displayed. The prefix is not sent to the cluster. Example: 20M sh/dx
  • When a connection drops out it will try to reconnect every 30 seconds
  • Ctrl+Alt+M changes the station status. For Multi-single, ctrl-alt-M changes toggles the station between Run and Mult status. For multi-2, ctrl-alt-M toggles the station between Run1 and Run2 status. This station status will be shown on the Cabrillo output.
  • In the multi-multi category the Cabrillo output will show the station number. In the multi-single category, the Cabrillo output will show whether the QSO was made by the Run or Mult station. In the mult-2 category, the Cabrillo output will show whether the QSO was made by the Run1 or Run2 station.
  • Any station that is harmonically related with the frequency will be colored red in the Info window
  • For single operator and multi-one, the operator callsign will be colored red when transmitting
  • Group edits are not allowed in the Log window while in Networked-Computer mode
  • If a station has selected 'Config | Networked-Computer Tools | Don't work non-mults' , CQing on that station is not allowed
  • Only the master station will auto-reconnect to packet/telnet when enabled

7. Example Networked-Computer Setup


The example below uses file sharing and Netbios lookup for computer (you can see them in the Networking environment). This is not necessary for N1MM logger to work in Networked-Computer mode. When the computers can be 'pinged' from both sides this is enough to work. All lines with a * are not necessary to work but are nice to have for other purposes like updating of files etc. This does not mean that the action mentioned should not be done. It can also be done via other media (CD / diskettes). In that case the Windows network is not used, as the N1MM network is using the TCP/IP stack only.

7.1. Before the Contest

NOTE: This has been copied verbatim from N1MM Classic, and is severely out of date. Do not rely on it.
Master computer

  • Enable File sharing for Windows networks (*)
  • Have all installation files ready on master (*)
  • Set Master IP address according to Station Computer Names list (see below)
    • Note previous IP setting for restoration after contest
  • Note master Windows computer (NetBIOS) name & workgroup (*)
  • Start N1MM Logger
  • Select a new empty database (e.g. PACC2003.MDB) on master
  • Start a new log for the contest (e.g. PACC) (check manual)
  • Configure Function keys (SSB/CW/Packet)
  • Edit Station Computer Names according to plan. For example:
    • Stn#:Stn Name Computer IP Address
    • 0:master
    • 1:160M
    • 2:80M
  • Load the relevant country file (e.g. CTY-PACC.DAT) (Tools menu)
  • Download the latest Master.scp file from the Internet (File>Download Latest Check Partial (master.scp)...)
  • Establish DX cluster communications on the master computer (Packet or Telnet)
  • Setup or disable internal firewall

Non-master computers

  • Install Network card& TCP/IP when not already done
  • Setup or disable internal firewall
  • Enable File sharing for Windows networks (*)
  • Set IP address according to Station Computer Names list
    • Note previous IP setting for restoration after contest
  • Find master on the Windows network (*)
    • Use Search Computers in Network Neighborhood/Places using the masters Windows computer (NetBIOS) name)
  • Install/Update N1MM Logger
    • Copy from master via network (*)
  • Copy database (eg.PACC2003.MDB) from master on this computer
    • Copy from master via network (*)
  • Copy WAV directory from master on this computer
    • Copy from master via network (*)

All computers

  • Start N1MM Logger
  • Import windows settings
  • Open database (e.g. PACC2003.MDB) ('File menu) | Select: PACC log')
  • Set Networked-Computer mode on
  • Setup configuration (Rig control, PTT, CW)
  • Turn off Windows sounds if using WAV files
    • Control Panel - Sounds - Scheme: No Sounds


  • Make sure you are running the same version of the program on all computers
  • Make sure you are using the same contest on all computers
  • Make sure that all computers have the same time zone and daylight savings offset
  • Preferable, see if all computers have the same regional settings for numbers, dates, currency, etc
  • Preferable, see if all computers have the same short and long date and time formats

7.2. During the Contest


  • Check master time setting regularly
    • Use Internet time server if possible so it is done automatically
  • Observe network status, and reconnect/resync if necessary on all computers
    • Note that a resync only imports QSOs to the computer you import from! The computer where the import comes from is not being updated with the log from computer where you import to. Stated another way, a workstation will always "pull" QSOs from another workstation log, it never "pushes" QSOs out.

 Changing Out a Computer During a Contest

The best way to swap out a computer in the middle of a contest is to simply leave the old computer in the computer names list, and add the new computer to the end of the computer names list.

The new computer should have a unique IP address - different than the old computer. Yes, you would have to change the computer names table on every computer in the network, but it is the most fail-safe method.

You should definitely NOT try changing the IP address of the new computer to the same IP address as the old computer, nor remove the old computer from the station computer names list. Doing either of those is asking for problems.

7.3. After the Contest


  • Make sure all used computers are connected
  • Do a resync on all computers
  • Check QSOs/multiplier status on all computers & compare
  • Copy & compact database (e.g. PACC2003.MDB) to backup directory
  • Restore IP settings & Windows sounds scheme on borrowed PCs

8. Networked-Computer Log Synchronization


Log synchronization is something you should run very infrequently. Each station has its own copy of the log, so syncing them is only necessary to keep track of mults. They will get out of sync when one of the stations goes off line. Generally, you should only need to resync the last hour, if you were disconnected for less time than that. If a new station comes on line, then one of the stations should email him their database, and he can resync the log when he gets it, for the few minutes he missed. Where it would take a long time is when a station was off for many hours, and you want to preserve any contacts that may be in his log, but not in the others.

9. Multi-Multi Distributed - Networked-Computers via the Internet


It is possible to set up N1MM Logger to allow some or all of the other stations outside your LAN to communicate over the internet. Possible uses for this feature are: Headquarters (HQ) stations in the IARU contest, the CQWW "Extreme" category, and distributed special event stations.

9.1. Configuration


There are some caveats when trying this. You need more than basic computer knowledge for this. You need to know about IP-addresses, firewalls, routers, port settings, NAT etc.

You need to know your computer (external) IP-address. When directly connected to the internet, this can be obtained using the program ipconfig. The command 'ipconfig' should be entered in a command (cmd) window to see the output. When your computer is in a LAN your connection to the internet will probably be made via a router. All computers will use internal IP-addresses; the router uses the external IP-address. This link will give your (external) ip-address: http://www.whatsmyip.org/

When a Networked-Computer connection is not working, check the external IP-addresses. It is strongly recommended that static external IP addresses be used. When DHCP is used to obtain the external IP address from the Internet Service Provider (ISP), the external IP address can change at random and unexpected times. You should not depend on Dynamic DNS (dyndns.org) and similar services to provide the correct IP address to other computers in the extended network. Often, the domain name-to-IP address mapping is stored in your local computer or router, and may not be updated by Dynamic DNS.

The router should be set up to route incoming UDP and TCP traffic to your local PC IP address. This is done using a router feature that is typically called Network Address Translation (NAT), Port Forwarding or Port Redirection.

The incoming port will be 12070 + Station Nr (0-15). 12070 is used for the first PC in the list, 12071 for the second etc.

You must also configure your computer and router Firewall(s) to allow port 12070 + Station Nr (0-15) to be passed for incoming UDP and TCP traffic.

>Config >Edit Station Computer Names

  • Computers using N1MM logger in the local network need to use the local IP address, computers outside the local network need to use the external ip-address from the external network. The router on the external network should use port forwarding to the correct computer using N1MM logger
  • Example setup:
    • The address is the local IP-address at my end (PA1M)
    • The first two entries are two instances of N1MM logger on two different PC's from Tom (N1MM)
    • Example 'Port redirection table' in the router used at PA1M, the given names differ per router brand:
      • Service name : N1MM (does not matter)
      • Protocol: TCP and UDP
      • Public Port: 12072
      • 12072 = 12070 + 2, my local pc which needs to be connected from the 'outside'
      • Private IP:
      • Private Port: 12072
      • Active: Yes
    • NB the IP-address given in this example is not the IP-address used by Tom, N1MM any more :-)

The latencies when we tested were in the 100 mSec range.

 IP Addresses

The list of IP addresses needs to be different on each machine. Make sure the remote machine has its external IP address, and the local machine(s) has its internal address

Example at PA1M


Configure router and firewall to pass and forward UDP and TCP port 12072 to

Example at N1MM


Configure router and firewall to pass and forward UDP and TCP port 12070 to
Configure router and firewall to pass and forward UDP and TCP port 12071 to

9.2. Footswitch Support for Lockout


Footswitch lockout support has been added for multiple distributed stations.

In the IARU contest a headquarters station is allowed to use multiple stations located within one IARU zone, but the rule of one signal per band/mode is still in effect. So there could be 2 (one running station and another looking for multiplier) or more stations on the same band and same mode and they should keep only one TX signal on this band at any time. Now you can hook up a footswitch to the LPT port 15 (the LPT port must be enabled even if it is not being used for other purposes. There is no special check box to turn the footswitch feature on/off). If the station is not in multi-multi operator category the footswitch will directly control PTT just like Alt+T. If it is a multi-multi station (connected to other stations on LAN or via the Internet in Multi User mode) it will prevent two stations on the network from both transmitting on the same band/mode combination.

This is a software lockout only, and is subject to network latencies. As such, it should be considered a backup. Multiple stations on the same band/mode should always coordinate operations (with the help of message passing over the network from the Info window), and not depend on software lockout to ensure compliance with contest rules.

Last Modification: 24 March 2016 09:05:35 EDT by VE3KI.