Signal Lab

Your RF System, End To End

The antenna is half the system. The other half is everything between the feedpoint and your radio — and that half is where most stations are won or lost. This page is the map: every piece of the feed side, what it does, and where to read deeper. Start here, follow the links, and your watts arrive where you meant to send them.

The whole system on one sheet. Every section below is a stop on this map.

1. The Feedpoint And The Ladder Line

Every Greyline is an off-center-fed vertical dipole. The feedpoint sits at the insulators, and a short run of ladder line carries the balanced signal away from the element — with the external section set to approximately 91 cm per the assembly documents. That length is not decoration; it is part of the match. Set it, clamp it, leave it.

2. The Transition: Balun Or Direct To The ATU

From the ladder line you have two clean paths. The standard build runs the ladder line to a base-mounted remote ATU, which handles the balanced-to-matched work right at the antenna — short unmatched run, tuner where the tuning is needed. The alternative, favored by high-power stations, inserts a balun at the ladder-to-coax transition and runs an isolation choke on the coax side; one operator in Iceland runs exactly this chain at 4 kW and calls it a system built like a legal argument. Read his full build →

3. The Common-Mode Choke: Placement By Station

The five snap-on ferrites in your black bag are the included choke, and where they go depends on where your tuner lives. Remote ATU at the base: all five on the shack-bound coax, radio side of the tuner. Tuner in the shack: split the job across the two ends of the coax — choke at the feedpoint end, stopping common-mode where the antenna excites it, and choke between the tuner and the radio. Ends of the line, never a choke floating mid-run in the unmatched section, where it only makes work for the ATU. The full physics, with W7EL, K9YC, W2DU, and W7SX carrying the argument: Where The Choke Goes →

4. The Coax Run

On the matched side, coax is a solved problem — but length and cable choice still tax you, and the tax compounds with frequency. Before you buy a longer run than you need, put your numbers into the calculator and watch where the dB go. Feedline Loss Calculator →

5. Lightning And Static

Disconnecting when weather approaches is rule one and no device replaces it. Beyond that, an arrestor in the coax run gives static buildup a path to ground before it becomes your radio's problem — and if your remote ATU takes power over the coax, choose a DC-pass arrestor so protection and power coexist. Operators in lightning country run both the discipline and the hardware.

6. Go Deeper

The Greyline Bookshelf → — Zavrel W7SX, Kraus, N6LF, K9YC, and Portune W6NBC: the published work under every page on this site. dBi Gain Optimizer → — what could your yard work? The Signal Report → — real operators running these exact systems.

Watch your system work tonight — live cluster, RBN, and band conditions run free on our DX Console, where Greyline owners glow gold.