SIGNAL LAB

LDG RT-100 Remote Tuner: Why We Bundle It

Short answer: the RT-100 is a 125-watt weatherproof remote tuner that lives at the base of the antenna, takes its power over the coax, and matches 160 through 6 meters at the push of the radio's tune button. We bundle it with Greyline antennas because a multiband vertical dipole presents a different impedance on every band, and the feedpoint is a natural place to handle that. Here is the reasoning, so you can judge it yourself.

Why This Antenna Wants A Tuner At All

A single-band antenna can be cut to resonance and left alone. A 160-6M vertical dipole cannot: the same physical length is electrically short on 80, near a wavelength on 20, and long on 10, so the feedpoint impedance swings widely from band to band. That is not a flaw -- it is the price of every band from one pole -- but it means something has to transform the match. The only question is where that something lives, and there are two right answers.

The Case For The Base

An indoor tuner makes the radio happy while the mismatch still stands on the whole run of coax between the shack and the antenna -- and as Walter Maxwell, W2DU, laid out in Reflections (the book that settled more feedline arguments than any other), mismatched line loss multiplies the cable's matched loss, band after band. A remote tuner at the base closes the mismatch at the antenna, so the feedline runs matched and quiet the whole way home. Decades of feedline-loss threads in the amateur archives re-litigate this and arrive where Maxwell did. We wrote the full teach with the loss math here: Indoor vs Remote Antenna Tuner: Where the ATU Belongs ->

The Case For The Shack -- Also Right

Plenty of fine stations run the tuner indoors: the one already in your radio, the trusted box on the desk, the high-power unit an amplifier demands. That works -- with one honest consequence. Because the mismatch rides the whole feedline, the coax itself now does more of the work, and cable quality stops being a detail and becomes part of the antenna. If the shack tuner is your path, spend where the physics says to: run the numbers in the Feedline Loss Calculator and feed the antenna with cable worthy of it -- the Greyline feed system exists for exactly this station. Either road works. One buys a tuner at the base; the other buys better wire. Both put more signal on the air than pretending the question away.

What The RT-100 Actually Is

The LDG RT-100 is a 125-watt autotuner in a weatherproof housing, fed and powered through the coax by its indoor bias tee -- no separate control cable, no wall wart at the pole. It remembers its matches, so returning to a band is near-instant. Wide matching range covers the swings a multiband vertical dipole presents across 160-6M. At the Greyline feedpoint it pairs with the 1:1 current choke that keeps the feedline out of the antenna's business -- the RF choke and precision feedline hardware ship in every Greyline box, and the correct floating balanced configuration is documented in our tuner and balun guide.

The Honest Limits

The RT-100 is rated 125 watts. Barefoot operation -- which is where most FT8, CW, and everyday SSB actually happens -- it handles with margin. If your station runs an amplifier at legal limit, this is not your tuner: run the antenna-only configuration with a high-power matching solution, the way our contest operators do. Bill, K3WA, runs his 24-foot DX Flagpole in contests at legal limit on 40-10M and worked 61 stations on 160 from an HOA lot -- same antenna, his own high-power feed arrangement. The physics of the pole does not change; only the box at the bottom does.

Why The Bundle

One order, one box, one price lower than the two pieces bought separately -- and a feed system that arrives configured the way the physics wants it. That is the whole pitch. No tricks, just a proven tuner in a sensible place.

See the 24' DX Flagpole + RT-100 bundle ->