DX Spots  AR-Cluster Sysop Manual

DX spots are the heart of the cluster system.  AR-Cluster uses the AR-Technology callsign lookup database for determining the location (state/province) of the spot for filtering purposes.  The expanded AR-Cluster protocol sends this and other information down to other AR-Cluster nodes so connecting nodes do not have the additional burden of reclassifying the spot parameters.  Logic to prevent spot dupes is built in the software.   Spot callsigns are validated and spots not passing validation are dumped and a "DX spot CALLSIGN not processed due to invalid call." Message appears in the log tab window.


Sysop features pertaining to DX spots include locking out spots and users from creating spots, plotting spot rates, updating the auto-country lookup, setting the parameters for spot band and mode and activating the OH2AQ spot grabber.  See the DX Spot section of the User Manual for details on user spot options.



Spot Lockout

Calls can be placed into the DX Spot Lockout list.  The Cfg>Lockout dialog allows the sysop the capability to edit call in the spot lockout list.  The SET/BADDX and SET/NOBADDX commands can also be used to add and remove calls from the DX spot lockout list.


Any users spotting a call in the lockout list will receive an echo of the spot but the spot will not be send to other users or sent to the network.   Calls like TE1ST can be used for testing purposes.  Also if the spotting stations call is in the list, it will be rejected the same.


set/baddx te5st      

set/nobaddx te5st      


The SET/BLOCKDX and SET/NOBLOCKDX commands can be used to restrict a call from making DX spots.  When a restricted user makes a DX announcement the file BlockDx.TXT is echoed back to the blocked user.  


set/blockdx mycall     

set/noblockdx mycall      


Spot Rate Plotting


AR-Cluster features the capability to plot DX spot rates based on queries into the DX database table.  This feature is available via the Sysop Plot Spot Rates option.  During contest activities or even after the contest you can gain a lot of knowledge into the spots sources, and applied filters.  The down arrow displays a calendar allowing the selection of a particular year, month and day.  The left and right arrows scroll the plot back and forward by days. 


The Plot Type box allows the selection of various plotting functions.  Current implemented plot types are:


Total Spots - Total spots per hour

Unique Spots - Plots unique DX spots

Unique Calls - Plots unique calls per hour

Unique Spotters - Plots unique spotters per hour

Unique Nodes - Plots unique spotting nodes per hour

Unique Countries - Plots unique countries spotted per hour

Unique CQ Zones - Plots unique CQ zones spotted per hour

Unique ITU Zones - Plots unique ITU zones spotted per hour

Unique Bands -  Plots unique bands per hour

Duplicate Spots - Plots duplicate spots in the system


The Unique plotting function totals the unique entries in the database.  For example if in the last hour there were three DX spots from JA, VK and JA the Unique Countries plot would indicate a count of 2 for the hour.


Other filter parameters allow you to further limit the plotting By:

Spot CTY - The country of the spots

Band - The band of the spots

Mode - The mode of the spots

Spotter QTH – Various selection criteria based on the location of the spotter:  country, state, US spots, non-us spots and a breakdown by call area.


There are some interesting things that you can do with the plots.  For example if you want to make a QSO with a specific country on a specific band, you can use the Unique Countries, select the band and run back a week or so and check the plot peaks for good propagation periods to the selected country.  Some of the new functionality puts a pretty good load on the database so expect slight delays on slower machines.



Spot Auto-Country

The AR-Cluster auto-country routine takes the entered DX spot call and automatically determines the country prefix, CTY.   The country prefixes are based on inputs from the ARRL.CTY file.  The latest CTY files can be downloaded from one of the following Internet sites:





       http://www.k1ea.com (click on the Country Files link)


The Cfg>AutoCountry menu allows the import of the latest CTY files into the AR-Cluster database.  The use of CTY files allows for easy update for country status changes.  Place the latest ARRL.CTY file in the AR-Cluster Configuration folder and select the import button on the auto-country configuration menu.  The import routine makes two passes through the AR-Cluster auto-country database table, one to remove existing data and a second to import the new data.  A progress bar shows the status of the import.


When a new country is added, the AR-Cluster Need’s database tables also will need to be updated.  The Needs tables will be updated with maintenance releases as they involve changes to the database schema.


If a new country is added, each of the user and node filters may need to be updated for each user as well.


Spot Band-Mode

AR-Cluster uses the band-mode data to determine the operating mode and band of the spot based on its reported frequency.  By setting a standard mode for a frequency range, filtering can then be applied based on the band and mode of the spot.  Sysops and users should be aware that sometimes a spot mode may be mis-classified if its out of its expected range of operation for the mode.  For example if a CW station operates on 14.088 MHz, it will be flagged with a mode of RTTY.  This sometimes happens during contest activities.  The sysop can make adjustments as needed to the Band-Mode filter using the Cfg>BandModeFilter dialog.


Spot Grabber

AR-Cluster includes a built-in spot grabber allowing the pulling of spots off the OH2AQ web system.  These spots are logged as being from the node call WEB/NodeCall.   Occasionally the format of the OH2AQ web site will change requiring a change in parsing software in ARC. 


The spot grabber can be controlled by the Cfg>Station dialog allows the activation of the spot grabber.  The sysop command SET/SPOTGRABBER can also be used to control the spot grabber.


set/spotgrabber on    

set/spotgrabber off


The RESTART/OH2AQ command can be used to restart the OH2AQ spot grabber




Note:  One thing we need to caution on is shadowing effects of running a spot grabber with a cluster.  This problem is not ARC specific and can occur with any cluster that has built in dupe checking logic.  Suppose we have only three nodes in a network as:  Node1, Node2 and Node3.   Node1 is a regional hub and most of the spot distribution is from Node1 to Node2 to Node3. 


Node2 decides to activate a spot grabber and pull spots from somewhere else in the network.  Node2 also decides he only wants to report the spots from the spot grabber to his local users so he adjusts the Hop Count appropriately.  Setting up a node in this configuration can cause a shadowing effect for other nodes downstream based on the timing of the arriving spots.    If a spot arrives at Node2 via the spot grabber before it arrives from Node1, than Node3 will never see the spot due to it being a dupe when it arrives the second time.


Thus the use of external spot grabbers including the OH2AQ spot grabber built into ARC are not recommended anywhere except for the hub nodes.


Broadcast UI

AR-Cluster also contains logic to broadcast DX spots in an unconnected protocol using AX25 Beacon/Broadcast UI.  The UI mode is an unconnected mode and it allows spots to be made to stations while they are unconnected.   Current support for the Broadcast UI mode is with both AGW DLL and AGW TCPIP.  BPQ support may be implemented at a future date.


The configuration is done in the Cfg>IoDevices dialog.  Select the AGW interface and select the number of beacons to transmit via the drop box.


Note:  The DX cluster network depends on spots.  We recommend that the Broadcast UI mode only be used during contests and on very busy networks.  You can run the Broadcast UI mode along with normal connections and thus contest station who are contributing spots would do a full connect and other stations would remain unconnected and receive the Broadcast UI packets.


DX Reports

AR-Cluster can also generate reports of spotting activities.  These reports contain valuable information especially after a contest.  Reports can be generated on a specific day or a range of days.  Note:  Some of the queries will hit the node database very hard especially if you run them for long periods.  The results of the queries are printed to the screen and also to the DxReport.txt in the debug folder.  Before you start a run, delete the DxReport.txt from the debug folder. 



sh/dx rpt01 3/3/2001

sh/dx rpt01 3/3/2001 3/4/2001      (ARRL SSB 2001 test)

sh/dx rpt02 3/3/2001 3/4/2001     

sh/dx rpt03 3/3/2001 3/4/2001     

sh/dx rpt04 3/3/2001 3/4/2001      

sh/dx rpt05 3/3/2001 3/4/2001     

sh/dx rpt06 3/3/2001 3/4/2001     


Currently there are 6 reports.

RPT01 - DX Spot Totals

RPT02 - DX Spots by Band

RPT03 - DX Spots by Node

RPT04 - DX Spots by DX Call

RPT05 - DX Spots by CTY

RPT06 - DX Spots by Spotter


Report RPT6 can also take optional SQL statements to further break down the display.  A report RPT06 with no SQL generates a list of all spotters with the # of spots by each spotter ranked by the number of spots. 


SH/DX RPT06 8/20/2001 8/30/2001


This report can be narrowed to display just the spotters in the state of Texas by the following.


SH/DX RPT06 8/20/2001 8/30/2001 AND SpotterSubCty = 'TX'


This report could be further narrowed to the three nodes in Austin Texas.


SH/DX RPT06 8/20/2001 8/30/2001 AND (FromNode = 'AB5K' OR FromNode = 'K5NA' OR FromNode = 'K5AB')


Sample reports for the ARRL SSB 2001 are shown below.  Some of the reports are very long and have been shortened to save space.


DX Spot Totals 3/3/2001 to 3/4/2001 de AB5K

Total Spots:      23059

US Spots:         17881

Non-US Spots:     5178

VE Spots:         310

K1 Spots:         4780

K2 Spots:         1571

K3 Spots:         1896

K4 Spots:         1243

K5 Spots:         911

K6 Spots:         2347

K7 Spots:         1001

K8 Spots:         731

K9 Spots:         1124

K0 Spots:         553

Duplicate Spots:  44

Unique Calls:     3291

Unique Spotters:  2760

Unique Nodes:     414

Unique Countries: 222

Unique CQ Zones:  38

Unique ITU Zones: 51

Unique Bands:     15



DX Spots by Band 3/3/2001 to 3/4/2001 de AB5K

BAND          # SPOTS

10             6789

20             5050

15             5029

40             2557

80             1361

6              469

2              466

160            385

12             271

17             207

30             176

70             162

MW             128

VLF            7

4MTR           2



DX Spots by Node 3/3/2001 to 3/4/2001 de AB5K

      Node          # SPOTS

AB5K-14        8520

N4TY           1143

W3LPL          954

K5NA           500

K6NP           469

N8TO           339

K4JA           338

K8TME          337

AA1K           333

K1AJ           300

W3MM           298

K6NDV          261

N7TR           244

K3WW           235

K7AR           234

KS9W           232

K1TTT          211

N2TX           207

K6EXO          204

KC1XX          196

K8AZ           187

WB6UCD         182

NC7J           174

K2TD           174



DX Spots by DX Call 3/3/2001 to 3/4/2001 de AB5K

Dx Call        # SPOTS

XA5T           228

ZF2NT          219

J38X           199

6Y8A           198

9M0M           184

VP2EK          182

RW2F           177

EA8BH          168

8P9JA          165

VP5B           163

PJ2K           154

FY5KE          142

P40W           140

9A7A           138

RU1A           136

IR4T           129

VP5A           127

V47KP          124

P40V           124

KH7Z           123

PJ4G           122

5U5A           120

C6A/N2VV       109

TM5C           105



DX Spots by CTY 3/3/2001 to 3/4/2001 de AB5K

CTY           # SPOTS

K              1242

I              1231

JA             983

DL             832

S5             774

LU             712

UA             590

PY             525

EA             501

KH6            456

F              430

XE             396

9A             391

ON             379

G              362

OK             355

SP             343

P4             309

PJ2            303

LY             298

VP5            293

UR             292

ZF             265

YU             261

6Y             260

UA9            257



DX Spots by Spotter 3/3/2001 to 3/4/2001 de AB5K

Spotter         # SPOTS

W3LPL          857

K4JA-7         364

NR1DX          363

K1RV           323

KR6C           285

W3PP           266

K1TTT-6        262

K9NS           252

NY6DX          249

K1TS           246

KC1XX          244

K3TG           233

W6AX           227

K8AZ-1         218

W6LAX          206

W1GQ-1         202

AC5AA          197

K1VV           176

W1MA           173

AA1ON          170

W2YC           170

W7IAN          160

W7ZR           154

KB1H           152

W9YK           147

AA1K-5         141

N3RR           140

WW3S           137