RF Guru
3.4kW DeltaRex - The Ultimate Low Angle DX Multiband Deltaloop
3.4kW DeltaRex - The Ultimate Low Angle DX Multiband Deltaloop
Couldn't load pickup availability
All our products are handmade, and fulfilment times may vary depending on order volume. Please allow 2–3 weeks for your order to be completed and shipped.
The DeltaRex is a solid, base station-class multiband delta loop antenna designed for high-performance DX and NVIS operation from 40m to 10m, with usable coverage on 60m and 80m NVIS. Engineered for durability and longevity, the DeltaRex features a heavy-duty triangular loop with a 120° base angle and a dual-wire wide-top conductor using 4 cm spacers to minimize RF loss and maximize long-term reliability.
The loop legs are built from 35 mm diameter, 2 mm wall thickness marine-grade aluminum tubing, while the base and all mechanical fittings use 3 mm 316 stainless steel (RVS) for maximum corrosion resistance. All other metallic components are also made from marine-grade RVS316.
Unlike portable loop systems, the DeltaRex is built for permanent installation and all-weather use, using high-quality components and robust mechanical design.
The antenna is fed at the bottom vertex using an included 4:1 UNUN, available in two power classes: 2.4 kW and 3.6 kW, depending on your needs. As a closed loop, the DeltaRex naturally exhibits excellent common-mode rejection compared to dipole-type antennas. For optimal coax decoupling, a 1:1 current choke should be placed at approximately 4 m from ground level, ideally at 0.05λ on the lowest operating band.
Operating Bands and Modes
| Band | Functionality | Notes |
|---|---|---|
| 10m | ✅ DX | Efficient, low-angle radiation |
| 12m | ✅ DX | Strong performance |
| 15m | ✅ DX | Slight multi-lobe pattern |
| 17m | ✅ DX | Good radiation, wide match |
| 20m | ✅ DX | Full-wave loop, strong DX |
| 30m | ✅ DX/NVIS | Mixed pattern, tunable |
| 40m | ✅ DX/NVIS | Efficient half-wave loop |
| 60m | ⚠ NVIS | Usable with tuner |
| 80m | ⚠ NVIS | Sub-resonant, low efficiency |
| 160m | ❌ Not supported | Too short for practical use |
Radiation Angles per Band and Mounting Height
| Bottom Height | 10m | 12m | 15m | 17m | 20m | 30m | 40m |
|---|---|---|---|---|---|---|---|
| 0.5 m | 18° | 20° | 22° | 25° | 30° | 45° | 60° |
| 2 m | 12° | 14° | 16° | 18° | 22° | 35° | 50° |
| 3 m | 10° | 12° | 14° | 16° | 20° | 30° | 45° |
| 4 m | 9° | 11° | 13° | 15° | 18° | 28° | 42° |
| 5 m | 8° | 10° | 12° | 14° | 17° | 26° | 40° |
Values are representative approximations of the peak radiation lobe elevation angle, based on simulation.
Recommended Mounting Heights
| Bottom Vertex Height | Top Wire Height | Best Bands | Radiation Angle Behavior |
|---|---|---|---|
| 0.5 m | ~5.5 m | 20–10m | More regional short skip, easy install |
| 2 m | ~7 m | 40–10m | Enhanced low angle, reduced ground loss |
| 3–4 m | ~8–9 m | 30–10m | Ideal for DX + moderate NVIS |
| 5 m | ~10 m | 40m & 30m peak | Deeper DX angles, some NVIS reach |
Feed System and Choke Recommendation
The DeltaRex comes with a 4:1 UNUN rated for either 2.4 kW or 3.6 kW. This is installed directly at the bottom vertex.
To suppress any residual feedline current and preserve the antenna’s symmetrical pattern, place a 1:1 current choke at approximately 4 m above ground level on the coax line.
Construction Highlights
- Triangular 120° geometry for optimal loop current symmetry
- Loop legs: 35 mm / 2 mm wall marine-grade aluminum tubing
- Base plate: 3 mm RVS316 stainless steel
- All fasteners and supports: RVS316 marine grade
- Dual-wire top conductor with 4 cm spacers for ultra-low RF loss
- Total wire length: ~22.4 m in triangular configuration
- Stable SWR across bands with tuner
- Built to last — not a portable antenna
Comparison to Other Antennas
Compared to our EFOC29 (an 80–10 m off-center-fed wire antenna with 4:1 UNUN and 29 m wire), the DeltaRex provides:
- More consistent pattern symmetry
- Lower ground coupling and better low-angle DX on 20–10 m
- Superior mechanical structure — the EFOC29 is more compact and lightweight, but with more common-mode vulnerability and less control over takeoff angle
Compared to the IronWave6 (a 6 m vertical with tuner at the base), the DeltaRex:
- Has far higher efficiency on 40m and 30m, and more gain on 20–10 m
- Doesn’t rely on tuner range or loading coil compromises
- Is larger and heavier but optimized for permanent performance
Compared to our Vertx206 (a vertical fan with individual quarter-wave elements from 20 m to 6 m):
- The DeltaRex covers more bands with a single loop and better NVIS support on 30/40/60/80m
- Vertx206 is ideal for low-angle DX on 20–6 m but not suitable for NVIS or full multiband loop-style operation
Compared to an EFHW8010 (which claims 80–10 m coverage via 49:1 matching):
- The DeltaRex avoids the high-Q, high-impedance, common-mode nightmare of EFHWs
- Delivers real radiation, not tuner illusions or backyard myths
- We do not offer the EFHW8010 because it fails our standards for efficiency, stability, and clean pattern behavior
Summary
The DeltaRex is the ideal permanent multiband loop antenna for the serious operator who wants reliable DX from 10–40 meters with NVIS capability on 60 and 80 meters, all in a rugged, corrosion-resistant triangular structure. No radials, no tuning traps — just performance by design.
Note: Operation on 160 m is not supported due to wire length constraints.
DeltaRex — A Solid DeltaLoop Built to last.
Share
