Your RF System, End To End
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.
Credit Where It Is Due
This diagram, and a good deal more than the diagram, traces to John Portune, W6NBC. His published writing on off-center-fed vertical dipoles helped put this class of antenna in front of the amateur community — and he contributed RF design refinements to the Greyline itself along the way. The antenna that ships today is what it is partly because of work he did. That is worth saying out loud rather than leaving in a footnote.
The Whole Feed System in Three Lines
The tuner does the matching, band by band. The 1:1 choke keeps RF off the outside of the feedline — at the feedpoint, or on the radio side of a remote tuner. And no 4:1 or 9:1 belongs anywhere in the chain: a multiband antenna presents a different impedance on every band, so no fixed ratio can match it.
1. The Feedpoint And The Ladder Line
Every Greyline is an off-center-fed vertical dipole. The feedpoint sits at the insulator between the two halves, and a short run of 450-ohm ladder line carries the signal down inside the pole to the base. The ladder line and its spacers come in your box; the feedline kit install guide walks the install step by step. Set it up per the guide, and leave it.
2. At The Base: Choose Your Feedline
At the base of the pole, the ladder line meets the feedline that runs to your tuner and radio, and you have real options. Most owners use the adapter in the box to join it to coax, then run the coax to a remote tuner right at the pole or to a tuner in the shack. You can also run ladder line all the way to a balanced tuner on an aerial run, or bury balanced twisted pair in metallic conduit. The common choice is not always the most efficient for a given run; compare them for yours in the Feedline Loss Calculator, and see every configuration on Feedline System Kits.
High-power stations build the same chain with heavier parts: a dedicated 1:1 current choke rated well above their power — for a legal-limit station, we recommend choke and feedpoint components rated around 5 kW, for margin that keeps them cool through long digital duty cycles. One operator in Iceland runs exactly this at QRO and calls it a system built like a legal argument. Read his full build →
3. The Choke: Where It Goes
The five snap-on ferrites in your box make the 1:1 choke, and the rule for placing any choke is simple. It goes at the feedpoint, where it stops common-mode current right where the antenna excites it. The one exception: if a remote tuner sits at the antenna, the choke goes on the radio side of the tuner. The same rule holds whatever choke you use — the included ferrites for barefoot stations, or a dedicated current choke for amplifier stations. The full physics, with W7EL and K9YC carrying the argument: Where The Choke Goes →
4. The Feedline Run
Behind a remote tuner, coax runs matched, and its loss is the spec-sheet number. With the tuner in the shack, the mismatch lives on the line, so the line’s quality matters more. Either way, 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. Grounding, Lightning, And Static
The antenna floats: it is a dipole, and nothing in its RF circuit connects to earth. Your station is a different matter and should surely be grounded. Our recommendation is the ARRL’s: follow its guidance for station grounding, bonding, and lightning surge protection. Ward Silver’s Grounding and Bonding for the Radio Amateur (ARRL) is the reference we point owners to.
What That Looks Like in Practice
A grounded bulkhead entry panel where the feedline enters the building — a single-point ground where every cable coming in passes through one bonded plate, bonded to your electrical service ground.
Lightning surge protectors along the coax — at the base of the antenna, at the building entry, or both — each bonded to ground, so a surge takes the short path to earth instead of the long path to your radio.
DC-pass protectors if your remote tuner takes power over the coax. Most surge protectors block DC by design and will silently kill a power-over-coax tuner.
And the discipline no device replaces: when weather approaches, disconnect. Operators in lightning country run both the discipline and the hardware.
6. Go Deeper
The Greyline Bookshelf → — Zavrel, 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.
The System, Shipped
Every Greyline antenna arrives with its feed side thought through: ladder line, spacers, the adapter, and the five-ferrite choke. Add the antenna that fits your sky and the system on this page is yours — shipped free to the USA and Canada.
Watch your system work tonight — live cluster, RBN, and band conditions run free on our DX Console, where Greyline owners glow gold.
Designed in Sun Valley, Idaho. Built by hand in the Mountain West. Questions about your feed system? Call 435-200-4902 — an operator answers.
73, Jon KL2A
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