RayCoupler
Compact HF/VHF directional coupler in two variants—100 W and 2 kW— with forward/reflected outputs for SWR, Return Loss, and power measurement. Pairs with RaySspaController and RayRigAntSw, and is intentionally designed for easy integration into third-party amplifiers, meters, or station controllers.
Overview
RayCoupler is a tandem-match HF/VHF directional coupler that provides low-distortion forward and reflected sample outputs for instrumentation or controller inputs. The board is available in two builds: a 100 W variant for bench/driver chains and a 2 kW high-power variant for linear amplifiers.
The sampling network targets approximately −58 dB (fixed resistor ladder) and is compatible with ADC front-ends (e.g., ADS1115), detector ICs (e.g., AD8307) or SDR (e.g., ANAN PureSignal) used by your station controller. It integrates seamlessly with RaySspaController for protection logic (SWR, over-drive) and connects inline via RayRigAntSw.
Both RayCoupler variants include an onboard square-wave frequency generator derived from the RF sample line. This enables an attached MCU (such as the RaySspaController) to automatically determine the operating band and switch low-pass filters or antenna relays accordingly. The output is a TTL-level square wave (÷4 prescaler) proportional to transmit frequency, suitable for direct measurement using a timer or frequency-counter input pin.
At a Glance
- • Two builds: 100 W and 2 kW
- • HF/VHF coverage: 1.8–54 MHz
- • Target sample: −58 dB (fixed)
- • Forward & Reflected outputs
- • Works with ADS1115 / AD8307 inputs
- • Pairs with RaySspaController for protection
Key Features
Tandem-Match Topology
- Wideband HF/VHF coupling, minimal insertion loss
- Open integration: drop-in with third-party controllers
- RaySspaController: SWR trips, over-drive protection (optional)
- Inline routing via RayRigAntSw or your own relay board
Two Power Classes
- 100 W: compact, bench & driver stage
- 2 kW: high-power traces & spacing
- Thermal and spacing rules for legal limit
Instrumentation-Ready
- Forward / Reflected outputs (0–3.3 V typical after scaling)
- ~−58 dB sample via resistor network
- Labeled headers for direct wiring to ADCs or detector modules
Fast Hardware Protection
- Jumper-select SWR trip (3:1 default)
- Jumper-select Forward over-drive threshold via trim pot
- Open-collector interrupt output, pulled low on triggers
- Trip LED indicator lights on active interrupt
- Millisecond response, independent of firmware
Controller Integration
- Connects to RaySspaController for SWR trips
- Inline with RayRigAntSw amp path (RFHigh/RFLow)
- Clean harnessing and labeled headers
Frequency Sense Output
- Output Level: 0 – 3.3 V (logic safe)
- Bandwidth: 1.8 MHz – 54 MHz (HF/VHF)
- Typical Output: ÷4 prescaler, ~50 % duty cycle square wave
- Test points: ÷1 prescaler, ÷2 prescaler, ~50 % duty cycle square wave
- Interface: Frequency-sense pin routed to SMA footprint
Layout & Materials
- PCB 1.6 mm FR-4 2oz heavier copper/clearances
- Generous creepage and via stitching
- Footprints for SO-239 or N-type connectors
Calibration & Tuning
- Trim resistor for setting forward over-drive threshold
- Flatness checks across bands (NanoVNA/SAA)
- Documentation with target slopes & tables
Hardware Overview
The coupler uses a tandem-match transformer pair on a ferrite core set, with forward and reflected detectors feeding a resistive sampler network. The 2 kW build increases copper weight, spacing, and thermal relief while retaining the same pinout for controller harnessing.
Electrical
- Forward/Reflected outputs (0–3.3 V typical after scaling)
- Sample target −55 dB (adjustable resistor network)
- Optional log detector (AD8307) footprint
Mechanical
- connector in/out footprint: SO-239 or N-Type
- Heavier 2oz copper, wide traces / clearances
- 100 W board: T1 & T2 single toroids 12T
- 2 kW board: T1 & T2 stacked toroids 16T
- Board size: L 115 mm x W 70 mm
Quick Specs
- Power Classes: 100 W / 2 kW
- Frequency: 1.8–54 MHz (160–6 m)
- Sample Level: ~−55 dB
- Outputs: FWD / REF (to ADC or detector)
- Trip Indicator: onboard LED illuminates when SWR or FWD over-drive interrupt triggers
- Integration: Controller-agnostic (RaySspaController, RayPowerMeter optional)
- Connectors: SO-239 or N-Type footprints
Available Variants
| Model | Power Range | Sample Port | Freq Port | Protection | Notes |
|---|---|---|---|---|---|
| RayCoupler-100W | 0 – 100 W HF/VHF | ≈ −55 dB nominal | TTL ÷4 square-wave output | Jumper-select – Over-drive trip | Compact tandem-match with trip LED indicator |
| RayCoupler-2 kW | 0 – 2000 W HF/VHF | ≈ −55 dB nominal | TTL ÷4 square-wave output | Jumper-select – SWR trip (3:1) | High-power tandem-match with trip LED indicator |
Purchase Options (Coming Soon)
Online ordering is not enabled yet. The options below show the planned RayCoupler variants and how they will appear once the RF StateSide store is live. For early interest or questions, feel free to contact me directly.
RayCoupler-100W
Assembled & tested
Price: $TBD USD
- 100 W HF/VHF
- Fully assembled PCB
- Bench/driver-stage friendly
RayCoupler-100W Kit
Unassembled kit
Price: $TBD USD
- 100 W HF/VHF m
- PCB + BOM / parts kit
- Ideal for homebrew builders
RayCoupler-2kW
Assembled & tested
Price: $TBD USD
- 0 – 2 kW HF/VHF
- High-power layout & clearances
- Ready for inline amplifier use
RayCoupler-2kW Kit
Unassembled kit
Price: $TBD USD
- 0 – 2 kW HF/VHF m
- PCB + parts kit (toroids, hardware)
- For experienced builders
Until the online store is live, you can email Ray (KB1SO) to discuss availability, pricing, or early-access hardware.
Gallery
Images of the completed RayCoupler assembly, PCB layout, and hardware details. These visuals provide an overview of the board construction, component placement, and the compact transformer-based coupler design.
Assembled Board
Fully assembled RayCoupler with dual Mix-43 ferrite transformers, hand-wound sampling toroids, precision SMD resistors, and signal-conditioning components. The board uses a low-loss layout optimized for HF/VHF transparency and stable coupling performance. This photo has been AI-enhanced to improve lighting and clarity; the physical product may differ slightly.
PCB Board
3D PCB render showing the RayCoupler’s component placement, transformer pads, RF input/output footprints, sample output & square wave prescaler footprints, and the compact signal processing stage. This representation illustrates the board layout, mounting holes, and mechanical interfaces prior to assembly.
Measured Performance
The RayCoupler was characterized with a vector network analyzer over the HF/VHF band. The measurements below show mainline return loss (S11), insertion loss (S21), and sampler-port coupling over a 2–54 MHz sweep.
S11 & S21 – 2 MHz to 54 MHz Sweep (Recalibrated)
The RayCoupler shows excellent transparency across the HF/VHF spectrum: at 3.6 MHz S11 ≈ −27.9 dB, S21 ≈ −0.218 dB; at 14.3 MHz S11 ≈ −30.38 dB, S21 ≈ −0.053 dB; and at 28.9 MHz S11 ≈ −27.06 dB, S21 ≈ −0.094 dB. This corresponds to a VSWR near 1.07:1 with < 0.25 dB insertion loss across 80 m through 10 m.
Sampler Port Coupling – 2 MHz to 54 MHz
The sampler port delivers a stable coupling level across HF/VHF: at 3.6 MHz S21 ≈ −61.76 dB; at 14.3 MHz S21 ≈ −57.95 dB; and at 28.9 MHz S21 ≈ −58.40 dB. The sample output is flat within a few dB from 80 m to 10 m, providing a clean –58 dB nominal sample suitable for power measurement, monitoring, or feedback into exciter ADCs (e.g., ANAN PureSignal).
Interested in RayCoupler?
If you're building an HF amplifier or need precise SWR, power, and sampler output for monitoring or linearization tools like ANAN PureSignal, RayCoupler can help. Contact me to learn more or request early hardware availability.