Practical operating recipes

Sample DX filters

Start with a complete example, then adapt it to your station, location and operating goal.

Save your current filter first. Run SHOW DX FILTER or SHOW DX OPTIONS and copy the reply. Every SET DX FILTER command below replaces your entire saved DX filter; it does not add another line to it.

These examples are practical starting points, not universal presets. A node can deliver only the feeds it receives. Your logger can hide additional reports after ARC6.6 sends them, but it cannot restore a report excluded by the server-side filter.

Everyday DX · FT4/FT8 · CW and RTTY · Phone and domestic contests · VHF and single-band · Save and reuse · Duplicate reduction

Before you paste a filter

Replace W1ABC with the callsign you use on the air.
Replace state, province, continent, country, zone, band and comment values to suit your location and event.
Send the complete SET DX FILTER command from your user login.
Use SET DX MODE FILTER, then confirm the result with SHOW DX OPTIONS.

CALL=W1ABC is an own-callsign inclusion choice. CALL is the station being spotted, not the spotter and not necessarily your login callsign. One final OR CALL=W1ABC is enough to retain worldwide human and CW/RTTY reports of your station. FT4/FT8 still requires positive FTSKIMMER in the same way the report matches. A recipe with an unrestricted OR FTSKIMMER needs only the final callsign choice; a geographically or otherwise restricted FT recipe needs (FTSKIMMER AND CALL=W1ABC) as a separate alternative when its worldwide own-callsign exception must include FT.

ARC6.6 evaluates AND before OR. Each part separated by OR is another way a report can match. Detailed explanations call each alternative a filter branch. Parentheses make those independent choices clear and help prevent a restriction from applying to only one of them by mistake.

Choose which report types to include

Report type	Typical filter condition	What it includes
Human reports	`NOT SKIMMER`	Reports submitted by operators rather than automatic receivers.
CT1BOH-qualified CW/RTTY skimmers	`SKIMVALID`	Automatic CW/RTTY reports that passed the node’s CT1BOH corroboration test.
FT4/FT8 skimmers	`FTSKIMMER`	Explicitly opts into FT Modes reports. `SKIMMER` alone does not opt into FT delivery.
Your on-air callsign	`CALL=W1ABC`	Includes worldwide human and CW/RTTY reports of your station that would otherwise miss the selected choices. Add `FTSKIMMER AND CALL=W1ABC` only when a restricted FT recipe must extend that exception to FT.

SKIMVALID, SKIMBUSTED, SKIMQSY and SKIMUNKNOWN are CT1BOH quality fields for CW/RTTY skimmer reports. They do not classify FT4/FT8 reports. In a mixed filter, keep CT1BOH conditions with the conventional SKIMMER choice and use a separate positive FTSKIMMER alternative.

Everyday DX operating

All spotters and all report families — DX outside K/VE

SET DX FILTER (SKIMVALID AND CTY<>[K,VE]) OR (FTSKIMMER AND CTY<>[K,VE]) OR (NOT SKIMMER AND CTY<>[K,VE] AND NOT COMMENT=[*BEACON*,*NCDXF*,*HEARD*]) OR (FTSKIMMER AND CALL=W1ABC) OR CALL=W1ABC

This is a broad daily DX filter. It accepts qualified CW/RTTY skimmer reports, FT reports and human reports for stations outside the K and VE entities, while always retaining reports of your own station.

North American spotters and all report families — DX outside K/VE

SET DX FILTER (SKIMVALID AND SPOTTERCONT=NA AND CTY<>[K,VE]) OR (FTSKIMMER AND SPOTTERCONT=NA AND CTY<>[K,VE]) OR (NOT SKIMMER AND SPOTTERCONT=NA AND CTY<>[K,VE]) OR (FTSKIMMER AND CALL=W1ABC) OR CALL=W1ABC

Every way a report can match applies the same North American spotter and outside-K/VE restrictions.

Western and central spotters and all report families — DX outside K/VE

SET DX FILTER (SKIMVALID AND SPOTTERSTATE=[AB,BC,WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,SD,ND,NE,KS,OK] AND CTY<>[K,VE]) OR (FTSKIMMER AND SPOTTERSTATE=[AB,BC,WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,SD,ND,NE,KS,OK] AND CTY<>[K,VE]) OR (NOT SKIMMER AND SPOTTERSTATE=[AB,BC,WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,SD,ND,NE,KS,OK] AND CTY<>[K,VE]) OR (FTSKIMMER AND CALL=W1ABC) OR CALL=W1ABC

Use this as a pattern, not a universal region. Add or remove states and provinces to match the receivers and operators most useful from your station.

Western and central skimmers, broader North American human reports — DX outside K/VE

SET DX FILTER ((SKIMVALID OR FTSKIMMER) AND SPOTTERSTATE=[AB,BC,WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,SD,ND,NE,KS,OK] AND CTY<>[K,VE]) OR (NOT SKIMMER AND SPOTTERCONT=NA AND CTY<>[K,VE]) OR (FTSKIMMER AND CALL=W1ABC) OR CALL=W1ABC

This groups CW/RTTY and FT skimmers because they share the same state/province list, while human reports use the broader North American continent test. The target-country condition remains in both geographic alternatives so the final own-callsign exceptions stay worldwide. Use grouped conditions only when the report types truly share those conditions.

Qualified CW/RTTY skimmers plus all FT skimmers

SET DX FILTER (SKIMVALID) OR FTSKIMMER OR CALL=W1ABC

This omits human reports except for the own-callsign choice.

Human reports only — North American spotters, DX outside K/VE

SET DX FILTER (NOT SKIMMER AND SPOTTERCONT=NA AND CTY<>[K,VE] AND NOT COMMENT=[*BEACON*,*NCDXF*,*HEARD*]) OR CALL=W1ABC

This excludes both CW/RTTY and FT skimmer reports.

Western spotters by ITU zone — DX outside K/VE

SET DX FILTER (UNIQUE>1 AND SPOTTERITUZONE=[2,6,7] AND CTY<>[K,VE] AND NOT COMMENT=[*BEACON*,*NCDXF*,*HEARD*]) OR (NOT SKIMMER AND SPOTTERITUZONE=[2,6,7] AND CTY<>[K,VE] AND NOT COMMENT=[*BEACON*,*NCDXF*,*HEARD*]) OR CALL=W1ABC

UNIQUE>1 asks for corroboration from more than one unique skimmer source. This example does not opt into FT Modes.

FT4 and FT8 examples

FT delivery requires positive FTSKIMMER in the way that report matches. A blank filter, SKIMMER alone, or SKIMVALID does not opt a user into FT4/FT8 reports.

Western FT skimmers — DX outside K/VE

SET DX FILTER (FTSKIMMER AND SPOTTERSTATE=[AB,BC,WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,SD,ND,NE,KS,OK] AND CTY<>[K,VE]) OR (FTSKIMMER AND CALL=W1ABC) OR CALL=W1ABC

North American FT skimmers — DX outside K/VE

SET DX FILTER (FTSKIMMER AND SPOTTERCONT=NA AND CTY<>[K,VE]) OR (FTSKIMMER AND CALL=W1ABC) OR CALL=W1ABC

Western FT skimmers — include K/VE

SET DX FILTER (FTSKIMMER AND SPOTTERSTATE=[AB,BC,WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,SD,ND,NE,KS,OK]) OR (FTSKIMMER AND CALL=W1ABC) OR CALL=W1ABC

Human spots, qualified CW/RTTY skimmers and FT skimmers

SET DX FILTER (NOT SKIMMER) OR (SKIMVALID) OR FTSKIMMER OR CALL=W1ABC

This is the simplest explicit all-family example. Add the same geographic or band condition to each report-type alternative when you want it to apply to every family.

CW and RTTY contest patterns

CWT / FOC — western and central spotters

SET DX FILTER (SKIMVALID AND FOC AND SPOTTERSTATE=[AB,WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY]) OR (NOT SKIMMER AND FOC AND SPOTTERCONT=NA) OR CALL=W1ABC

CQWW CW on 160 meters — K/VE spotters

SET DX FILTER (SKIMVALID AND SPOTTERCTY=[K,VE] AND BAND=160) OR (NOT SKIMMER AND SPOTTERCTY=[K,VE] AND BAND=160 AND NOT COMMENT=[*FT8*,*FT4*,*BEACON*,*HEARD*,*RTTY*]) OR CALL=W1ABC

Remote East Coast receiver view — DX outside K/VE

SET DX FILTER (SKIMVALID AND SPOTTERSTATE=[FL,GA,SC,NC,VA,WV,DE,NJ,PA,CT,NY,MA,VT,ME,RI] AND CTY<>[K,VE]) OR (NOT SKIMMER AND SPOTTERSTATE=[FL,GA,SC,NC,VA,WV,DE,NJ,PA,CT,NY,MA,VT,ME,RI] AND CTY<>[K,VE]) OR CALL=W1ABC

NAQP RTTY — North American spotters and targets

SET DX FILTER (SKIMMER AND SPOTTERCONT=NA AND CONT=NA AND COMMENT=[*RTTY*,*NAQP*]) OR (NOT SKIMMER AND SPOTTERCONT=NA AND CONT=NA AND COMMENT=[*RTTY*,*NAQP*]) OR CALL=W1ABC

North American RTTY / BARTG

SET DX FILTER (SKIMMER AND SPOTTERSTATE=[AB,WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,SD,ND,NE,KS,OK,WI,IL,MN,IA,MO,AR,LA,OH,KY,TN,AL] AND COMMENT=[*RTTY*]) OR (NOT SKIMMER AND SPOTTERCONT=NA AND COMMENT=[*RTTY*,*BARTG*] AND NOT COMMENT=[*BEACON*,*NCDXF*,*HEARD*]) OR CALL=W1ABC

Phone and domestic contest patterns

ARRL Sweepstakes CW

SET DX FILTER (SKIMMER AND UNIQUE>2 AND SPOTTERCONT=NA AND CTY=[K,KL,VE,KH6,KP2,KP4] AND NOT COMMENT=[*RTTY*,*BEACON*]) OR (NOT SKIMMER AND SPOTTERCONT=NA AND CTY=[K,KL,VE,KH6,KP2,KP4] AND NOT COMMENT=[*RTTY*,*BEACON*]) OR CALL=W1ABC

ARRL Sweepstakes SSB — human spots

SET DX FILTER (NOT SKIMMER AND SPOTTERCONT=NA AND CTY=[K,KL,VE,KH6,KP2,KP4] AND NOT COMMENT=[*RTTY*,*BEACON*]) OR CALL=W1ABC

CQWW DX SSB — human spots outside K

SET DX FILTER (NOT SKIMMER AND SPOTTERCONT=NA AND CTY<>K AND NOT COMMENT=[*RTTY*,*BEACON*]) OR CALL=W1ABC

Pennsylvania QSO Party

SET DX FILTER (SKIMMER AND UNIQUE>1 AND SPOTTERCONT=NA AND CTY=K AND STATE=PA) OR (NOT SKIMMER AND CTY=K AND STATE=PA) OR CALL=W1ABC

California QSO Party

SET DX FILTER (SKIMMER AND UNIQUE>1 AND SPOTTERCONT=NA AND CTY=K AND STATE=CA) OR (NOT SKIMMER AND CTY=K AND STATE=CA) OR CALL=W1ABC

7QP and regional QSO parties

SET DX FILTER (SKIMVALID AND NOT SKIMBUSTED AND SPOTTERSTATE=[WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,ND,SD,NE,AB,KS,OK,TX]) OR (NOT SKIMMER AND COMMENT=[*7QP*,*IQP*,*NEQP*,*DQP*,*NQP*,*DEQP*,*QSO*,*PARTY*] AND NOT COMMENT=[*BEACON*,*NCDXF*,*HEARD*]) OR CALL=W1ABC

VHF and single-band patterns

6-meter contest

SET DX FILTER (SKIMMER AND SPOTTERSTATE=[WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,ND,SD,NE,KS,OK,TX,MN,IA,MI,AR,MS,LA] AND BAND=6) OR (NOT SKIMMER AND SPOTTERSTATE=[WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,ND,SD,NE,KS,OK,TX,MN,IA,MI,AR,MS,LA] AND BAND=6) OR CALL=W1ABC

10-meter contest

SET DX FILTER (SKIMMER AND SPOTTERSTATE=[WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,ND,SD,NE,KS,OK,TX,MN,IA,MI,AR,MS,LA] AND BAND=10) OR (NOT SKIMMER AND SPOTTERSTATE=[WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,ND,SD,NE,KS,OK,TX,MN,IA,MI,AR,MS,LA] AND BAND=10) OR CALL=W1ABC

50–55 MHz plus western DX

SET DX FILTER (SKIMMER AND SPOTTERSTATE=[AB,WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,ND,SD,NE,KS,TX] AND FREQ WITHIN (50000/55000)) OR (SKIMMER AND SPOTTERSTATE=[AB,WA,OR,CA,NV,ID,MT,UT,AZ,NM,CO,WY,ND,SD,NE,KS,TX] AND CTY<>[K,VE]) OR CALL=W1ABC

Save and reuse these filters

After setting and checking a complete filter, save the active expression under a memorable name. Useful names include Daily DX, ARRL DX CW, CQWW CW and CWT. Activate the corresponding filter before saving each name; running several SAVE commands in a row would store the same active expression under several names.

SAVE DX FILTER CQWW CW
LIST DX FILTERS
LOAD DX FILTER CQWW CW
DELETE DX FILTER CQWW CW

SAVE stores the current nonempty DX filter. LOAD validates and activates the named expression. DELETE removes the named copy but leaves the active filter running. Named filters belong to your callsign/SSID on that node. See the saved DX filters guide and complete command reference for limits, numbering and additional examples.

Reduce repeated skimmer reports

NOT SKIMDUPE keeps reports whose server-side skimmer-duplicate flag is clear. ARC6.6 lets the first skimmer report for a callsign and band through as nonduplicate, then marks later reports as duplicates for ten minutes while they remain within the node’s configured frequency tolerance. A move outside that tolerance or expiration of the window establishes a new first report. FT4 and FT8 use separate duplicate identities.

Duplicate detection happens before your personal filter is evaluated. Every delivered report still must satisfy all conditions joined with AND, but ARC6.6 does not skip a nonqualifying first report and promote the next qualifying duplicate. The first report in the server-wide duplicate group is not necessarily the first one that also meets your location, SNR, CT1BOH or other criteria. Combine NOT SKIMDUPE with those conditions only when you accept that their strict intersection can deliver no report from a group. Keep it with a positive SKIMMER or FTSKIMMER condition; by itself, NOT SKIMDUPE also matches ordinary human reports because they are not marked as skimmer duplicates.

First conventional CW/RTTY skimmer report in each duplicate group

SET DX FILTER SKIMMER AND NOT SKIMDUPE

This substantially reduces repeated CW/RTTY skimmer reports. It does not require CT1BOH validation, opt into FT delivery or add an own-callsign exception.

First FT report in each duplicate group

SET DX FILTER FTSKIMMER AND NOT SKIMDUPE

This applies duplicate suppression to FT reports. It does not include human or conventional CW/RTTY reports and does not add an own-callsign exception.

Adapt a recipe safely

If you change…	Check this
`CALL`	Use the callsign you operate on the air. This is the spotted station, not the spotter.
`CTY` / `CONT` / `STATE`	These describe the spotted station.
`SPOTTERCTY` / `SPOTTERCONT` / `SPOTTERSTATE`	These describe the operator or receiver that submitted the report.
Bands or geography	Repeat the condition in every human, CW/RTTY and FT alternative that should obey it.
FT Modes	Keep positive `FTSKIMMER` in the matching alternative. Do not add `SKIMVALID` to the FT alternative.
`NOT SKIMDUPE`	Keep it with the skimmer condition it should limit. It selects the first server-wide duplicate-group report, not the first report that passes your other criteria.
Comments	Wildcards such as `BEACON` search for text containing the word. Comment conventions vary by source.

After changing a filter, read the server’s confirmation and run SHOW DX OPTIONS. If expected spots are missing, temporarily simplify one alternative at a time and confirm that the node actually receives that feed. See the filtering chapter, FT Modes chapter and complete command reference for field and command details.

Examples curated from long-term operating filters maintained by NG7M. Original AR-Cluster implementation: Terry Gerdes, AB5K (SK). CT1BOH algorithm: José Nunes, CT1BOH.

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