Remote ATU · System Completion
LDG RT-100 Remote ATU for Greyline VDA Systems
The LDG RT-100 is the remote automatic antenna tuner Greyline pairs with VDA flagpole systems for buyers who want one cart, one shipment, and one support relationship. Mounted at the antenna feedpoint. Weatherproof. 100 watts. Matched to the Greyline 20DXF as a bundled stealth HF system or sold standalone to Greyline owners completing an installation.
Who This Page Is For
Greyline Antenna Owners Completing Their System
If you own or are buying a Greyline VDA and want the matched remote tuner from the supplier who already knows your antenna, you’re in the right place. One cart. One shipment. One phone number when you have a question at 9pm on a Saturday.
If you’re shopping remote tuners as a category, DX Engineering and Ham Radio Outlet carry this same unit and will serve you well. Our pricing here reflects the cost of running a matched-system support channel for Greyline buyers — not a race to undercut the tuner market.
The Physics
Why a Remote ATU with a VDA Flagpole
A remote tuner is mounted at the antenna feedpoint, not in the shack. When SWR climbs on a given band, coax loss climbs with it. A tuner in the shack corrects the match your transceiver sees, but the feedline still carries the mismatched current — and that power converts to heat in the coax.
A remote ATU corrects the match at the antenna, so the feedline operates at or near 50 ohms the whole way back to the shack. On a 75-foot or 100-foot run of LMR-400 or LMR-600, the difference is measurable — especially on the higher bands and under high-duty-cycle modes like FT8.
Honest counterpoint. Roughly half of Greyline buyers prefer a desktop shack ATU instead — including RF engineers who want hands-on tuning and manual memory control. Both paths work. If your rig has a capable internal tuner and your feedline is short and well-chosen, you may not need an external tuner at all.
The remote-vs-shack decision is yours to make, not ours to force. This page is for operators who’ve decided a remote tuner is the right answer for their installation.
Specifications
LDG RT-100 — The Numbers
Power & Frequency
Power: 0.1 to 100 watts SSB and CW
Frequency: 1.8 – 54 MHz (160M – 6M)
Matching range: 6 – 1000 ohms SSB, 12 – 800 ohms CW
Tuning & Memory
Full tune: 0.1 to 6 seconds
Memory recall: Under 0.5 seconds
Memories: 2,000 for instant recall
Enclosure & Mounting
Weatherproofing: Sealed for outdoor mount
Location: At the antenna feedpoint
Control & Power
Control: Radio interface cable or manual control box
Power required: 12 VDC at the tuner
Before You Buy
Duty Cycle — What to Know
The RT-100 is rated at 100 watts. That rating assumes SSB and CW duty cycles. If you run FT8, RTTY, or other high-duty-cycle digital modes at or near full power, derate accordingly — the same way you would with any 100-watt tuner from any manufacturer.
For 100W FT8 operation, run at 50–75W out of the transceiver, not 100W. The relay contacts and L/C components will last longer. If you’re a legal-limit operator or plan to run high-duty digital at full power, skip the RT-100 and move up to a desktop ATU rated for your mode — a Palstar HF-AUTO or similar.
Our Rule
We’d rather tell you this honestly than sell you the wrong tool. If you’re unsure whether the RT-100 is right for your rig and mode profile, call us before you buy. Five minutes on the phone saves a lot of returns.
Bundle Path
Buying Both? Take the Bundle
If you’re ordering an antenna and a remote tuner together, the bundle page is the right move. One cart, one shipment, pre-matched components, and a modest savings over buying the two items separately.
20DXF + RT-100 Bundle
The 20-foot DX Flagpole antenna matched with the LDG RT-100 remote tuner, pre-configured and shipped as one system. Designed for stealth HF installations in HOA and property-restricted environments.
Standalone RT-100 pricing on this page is for Greyline antenna owners completing a system they already own, or adding a second tuner for a different installation.
What Ships
What’s in the Box
- LDG RT-100 Remote Automatic Tuner (sealed outdoor enclosure)
- LDG documentation and quick-start guide
- Greyline matched-system support — 435-200-4902
Interface cable to your specific radio, weatherproofing tape, and bias-tee components (if using a single coax run for RF plus DC) are typically purchased separately based on your rig and feedline choice. If you’re not sure what you need, call before you buy. We do this every day.
A Note on ATU Selection
Greyline sold hundreds of automatic tuners before the 2020–2022 industry shake-up thinned the field. We’re rebuilding that side of the catalog deliberately, starting with the units we’ve paired successfully with VDA systems for years.
If you have a specific ATU question — matching range, duty cycle, remote vs. shack placement, or how it will behave with your specific rig — pick up the phone.
Ham Radio is fun again! Pass it on... 73, The Greyline Performance Team