Does the DeltaRex need radials?

No. DeltaRex is a closed-loop antenna and does not require a radial system.

Do I need an external tuner with the DeltaRex?

On all bands an internal ATU is sufficient, except on 30, 60 and 80 m where an external tuner is required.

Where should I place the common-mode choke?

Place a 1:1 current choke ~8 m down the coax (≈0.1λ). Always use at least a 26 m feedline to the shack and a choke before shack entry.

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RF Guru

3.6kW DeltaRex — The Ultimate Low Angle DX Multiband Deltaloop

€497,00 EUR

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High Power 4:1 Balun with PL Socket 2.4kW 3.6kW

Aluminium Poles 2x 6M None (DiY)

Product variants

Quantity

Disclaimer: All RF.Guru products are handmade. Fulfillment may vary depending on order volume. Please allow 1–3 weeks for assembly and shipping.

Note: You can order without the two 6 m aluminum poles (source them locally). We provide all necessary parts except the poles — you only need to drill 2 holes and mount 2 RVS eyelets. The transformer is available in 2.6 kW or 3.6 kW ICAS versions.

⚠️ This antenna is only compatible with the smaller ballast frame using a 2 m pole — it cannot be mounted on the 1.1 m pole.

US Aluminum Pole Reference

Recommended US-sourced tube (close to our 6 m × 35 mm OD × ~2 mm wall marine tube):

• Alloy/temper: 6061-T6 or 6063-T52
• Outside diameter: 1-3/8 in (≈34.93 mm)
• Wall thickness: 0.083 in (≈2.11 mm)
• Length: ~20 ft (≈6.1 m)

Ask for: “1-3/8 in OD × 0.083 in wall × 20 ft 6061-T6 (or 6063-T52) aluminum tube” at OnlineMetals, Metal Supermarkets, or local marine/awning suppliers.

DeltaRex is a base station-class multiband delta loop for DX and NVIS from 40 m to 10 m, with usable 60/80 m NVIS. It uses a 120° bottom vertex and a dual-wire wide-top conductor on ~5 cm spacers to reduce loss and keep patterns stable.

Loop legs are 35 mm OD, 2 mm wall marine-grade aluminum; base/fittings are 3 mm RVS316. All hardware is marine-grade for all-weather durability.

It is fed at the bottom vertex via the included 4:1 UNUN (rated 2.6 kW or 3.6 kW ICAS). Place a 1:1 current choke at ~8 m down the coax (≈0.1λ of the lowest band). Use at least a 26 m feedline to the shack and add a second choke before shack entry.

Specs at a Glance

Frequency coverage	80–6 m (DX focus 40–10 m; NVIS usable on 80/60 m)
Feedpoint impedance	~100–150 Ω (transformed to ~23–30 Ω via included 4:1 UNUN)
Power handling	2.6 kW or 3.6 kW ICAS versions
Polarization	Horizontal
Choke recommendation	1:1 current choke at ~8 m (≈0.1λ). Use minimum 26 m coax to shack + choke before shack entry.
Footprint	~11 m top span, ~22.4 m perimeter
Mechanical	35 mm / 2 mm wall Al tubing; 3 mm RVS316 stainless base/fittings

VSWR Sweep

DeltaRex SWR sweep across 80–10 m

(Indicative) — measured at the feedpoint with the included 4:1 UNUN and a 1:1 current choke ~8 m down the coax (≈0.1λ). Expect small shifts with height and surroundings. Use at least 26 m feedline and add a choke before shack entry.

Feed System & Choking

Typical loop feed impedance is ~100–150 Ω, transformed by the included 4:1 UNUN to ~23–30 Ω. Place a 1:1 current choke at ~8 m (≈0.1λ). Use at least a 26 m feedline and add a second choke before the shack entry for consistent pattern and lower noise.

Mini-FAQ

Does the DeltaRex need radials? — No, it’s a closed loop.
Do I need an external tuner? — On all bands an internal ATU is sufficient, except on 30, 60 and 80 m where an external tuner is required.
Where should I place the choke? — At ~8 m down the coax line (≈0.1λ). Always use ~26 m coax minimum and a choke at the shack entry.