What grid square is the JA04 operating area?

JA04 is the live DXRadar reference square for the JA04 operating area. The exact portable or home QTH may vary within the square, but this page tracks the center of JA04 for planning propagation.

How do I find my grid square?

Use a Maidenhead grid lookup from your GPS coordinates or street address, then compare that grid with the nearby squares linked on this page. A 4-character grid is enough for most HF planning.

What bands are open in JA04 right now?

JA04 is currently rated FAIR. The best bands right now are 10m, 20m, 30m, 40m, 60m, with 10m as the main band to watch first.

Grid JA04 Band Conditions

Localized HF conditions for Maidenhead locator JA04. Coordinating at -85.50°, 1.00°. Updated with real-time telemetry from NOAA and DX cluster reports.

JA04 conditions are FAIR. Best bands: 10m, 20m, 30m, 40m, 60m. SFI: 121.

Regional Radar

SFI

121

K-Index

1.67 Kp

Center Coords

-85.5, 1.0

Local Phase

Night

Grayline window

Sunrise 05:06 UTC

Sunset 18:32 UTC from JA04

From the JA04 operating area, work the 05:06 UTC and 18:32 UTC grayline windows: probe 20m, 30m, and 40m in the 15 minutes either side while the terminator crosses JA04.

Best band now

10m

Night operation should keep 20m on watch and move to 40m as the path darkens.

Closest operating hub

the JA04 operating area

This square sits in a mixed-region footprint and is best used as a planning center for portable, field-day, and home-station band decisions.

Latitude zone: high-latitude
Local phase: Darkness
Aurora exposure: watch during geomagnetic storms
Grayline: 05:06 UTC / 18:32 UTC
Best high band: 10m
Nearest city: the JA04 operating area

● Local Band Quality Scorings

Use this local score for JA04, then compare the global live ranking oncurrent ham band conditionsbefore changing bands.

10m

POOR

15m

POOR

20m

FAIR

40m

EXCELLENT

80m

EXCELLENT

● Best DX Windows from JA04 — the JA04 operating area

Great-circle distance, short-path beam heading, the bands most likely open right now from JA04 to each DX region at SFI 121 / Kp 1.67, and a current verdict. "Open now" means a suitable band is scoring well on that path; "Try ~HH:MM" points at the next far-end grayline. Band picks and status are a planning heuristic, not a measurement.

Target	Distance	Beam	Bands to try	Status
Southern Africa	4,141 mi	26°	40m, 20m, 80m	Open now
Oceania	4,414 mi	150°	40m, 20m, 80m	Open now
South America	5,024 mi	300°	40m, 20m, 80m	Open now
South Asia	7,664 mi	75°	40m, 20m, 80m	Open now
East Asia / Japan	8,929 mi	135°	40m, 20m, 80m	Open now
North America	8,952 mi	265°	40m, 20m, 80m	Open now
Europe	9,366 mi	8°	40m, 20m, 80m	Open now

● Band-by-Time Plan for JA04

A planning heuristic for the local day at JA04, built from sunrise 05:06 UTC, sunset 18:32 UTC, SFI 121, and Kp 1.67. Not a measurement — a starting point for where to listen as the day turns.

Dawn grayline

around 05:06 UTC

40m · 30m · 20m

Grayline enhancement — low bands reach long distances as the terminator passes.

Morning

after 05:06 UTC

20m · 15m · 10m

High bands rising with the sun; check 10m for DX.

Midday

local noon

10m · 15m · 20m

Peak high-band window — 10m and 15m open widest.

Dusk grayline

around 18:32 UTC

20m · 40m

Second grayline peak — 20m holds, then hands off to 40m.

Night

after 18:32 UTC

40m · 80m

Low bands own the darkness — 40m for DX, 80m regional.

Recent local activity

Spots touching JA04 and the adjacent squares

These are the newest 10m, 15m, and 20m reports where one side of the path sits in JA04, JA05, JA03, JA14, IA94. This gives the page unique, local context instead of a generic solar snapshot.

No fresh PSKReporter paths are cached for the immediate JA04 footprint right now. That usually means you should widen the search to the nearest regional hubs below or fall back to 20m/40m for the next operating window.

Top DX targets

Where this grid is reaching right now

No outbound targets were strong enough to rank from the current cache. Check back after the next PSKReporter refresh or switch to the regional grids below.

Contest preview

Next major contest outlook

CQ World Wide DX Contest - SSB starts Sat, 24 Oct 2026 00:00:00 GMT. Current forecast from JA04: 10m POOR, 15m POOR, 20m FAIR. Current solar conditions (SFI 121, K 1.67) favor 10m, 15m, 20m for this contest weekend.

Open contest calendar

Nearby grids