FCC Experimental Station • WQ2XDM • Grid: EL98BT • Florida, USA

WQ2XDM Propagation Research

Florida-based experimental station studying low-VHF propagation on the 4 meter (70 MHz) and 8 meter (40 MHz) bands using weak-signal digital modes including WSPR and FT8.

About

WQ2XDM conducts structured propagation testing to better understand Sporadic-E, Trans-Equatorial Propagation (TEP), low-VHF path behavior, and seasonal propagation trends. Testing emphasizes repeatable methods (consistent power, controlled operating windows, and stable station configuration) for meaningful comparisons over time.

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Technical Information (1–10)

1) Objectives

  • Measure and characterize low-power propagation on 8 m (40 MHz) and 4 m (70 MHz) using FT8 and WSPR.
  • Document seasonal and solar-cycle effects over 24 months.
  • Publish an open dataset and final white paper.
  • Provide comparative results with international amateur communities active in these bands.

2) Operating Location & Antenna

Public Grid: EL98BT (Tavares, FL area)
Antenna: Single-band ½-wave dipole at ≤ 6 m (20 ft) AGL
Polarization / Gain: Horizontal / ~2 dBi broadside
Feedline & Filtering: Coax + band-pass filtering, harmonic suppression ≥ 50 dB

3) Requested Frequencies, Modes, and Maximum ERP

  • 8 m: 40.660–40.700 MHz
    • WSPR beacon: 40.662 MHz — max 10 W ERP, 20% duty cycle
    • FT8 test windows: 40.680–40.690 MHz — max 25 W ERP, < 10 minutes per session
  • 4 m: 70.000–70.200 MHz
    • WSPR beacon: 70.005 MHz — max 5 W ERP, 10% duty cycle, nighttime only
    • Optional FT8 skeds: narrow windows — max 10 W ERP, ≤ 5 minutes per session

4) Why Florida is Essential

  • Low latitude: captures Trans-Equatorial Propagation (TEP) and equatorial ionospheric phenomena.
  • International alignment: direct paths to Caribbean & South America.
  • Unique environment: recurring Gulf/Atlantic tropo ducting and storm-driven disturbances.
  • Fills a national gap: systematic U.S. southeast comparisons on these bands.

5) Interference Mitigations

  • Ultra-narrowband FT8 and WSPR only.
  • ERP limits, strict duty cycles, and short test schedules.
  • Filtering/harmonic suppression ≥ 50 dB.
  • Remote “kill switch” and immediate cessation upon any interference report.

6) Data Handling

  • Automatic collection via PSK Reporter and WSPRnet.
  • Weekly raw log exports; monthly summaries published.
  • Final dataset and white paper published openly.

7) International Communications Authority

Exchange of test transmissions only (FT8/WSPR signal reports) with foreign stations where 4 m and/or 8 m operation is authorized.

8) Station Identification & Term

  • Identify with assigned experimental call sign at least every 30 minutes.
  • Logs maintained per experimental requirements.
  • Requested term: 24 months.

9) Precedent

  • WL2XUP: 8 m authorization (40.660–40.700 MHz).
  • WG2XPN: 4 m beacon at 70.005 MHz.
  • WD2XSH: ARRL 500 kHz project.

10) International Allocations & Comparative Value

Cross-band studies are supported by 8 m and/or 4 m activity in parts of Europe, South Africa, and other regions.