Skip to content

Your cart is empty

Continue shopping

Your cart

Loading...

Estimated total

€0,00 EUR

Tax included and shipping and discounts calculated at checkout

Electronics & Antennas for Ham Radio

  • New
  • Hot
  • HotSpot
    • VHF
    • UHF
  • Repeater
    • ON0ORA
  • BalUn/UnUn
    • Balun
    • Unun
  • Isolators
    • Line Isolators
    • Surge Protection
  • Filters
    • VHF-UHF Filter
    • Line Filters
  • Antenna
    • HF Active RX Antenna
    • HF End Fed Wire Antenna
    • HF Verticals - V-Dipoles
    • HF Rigid Loops
    • HF Doublets - Inverted Vs
    • UHF Antenna
    • VHF Antenna
    • Dualband VHF-UHF
    • Grounding
    • Masts
    • Guy Ropes & Accessories
    • GPS Antenna
    • Mobile Antenna
    • Handheld Antenna
    • ISM Antenna 433/868
    • Antenna Tools
    • Anti-Corrosion Lubricants
    • Dummy Load
  • Coax
    • Coaxial Seal
    • Coax Connectors
    • Panel Mount Connectors
    • Coax Adaptors
    • Coax Tools
    • Coax Cable
    • Coax Surge protection
    • Jumper - Patch cable
  • 13.8 V
    • DC-DC
    • AC-DC
    • Powerpole
    • 13.8 V Cable
  • PA
    • VHF Power Amplifiers
    • UHF Power Amplifiers
  • Parts
    • Ferrite
    • Pi
    • Routers
  • PCB
  • SDR
  • APRS
  • KB
    • Product Whitepapers
    • Knowledge Base
    • Transmit Antennas
    • Baluns and Ununs
    • Receive Antennas & Arrays
    • Technical Deep Dives
    • Debunking Myths
    • Transmission lines
    • Radio Interference
    • Grounding and safety
    • Ham Radio 101
    • Calculators
    • Ham Florida Man
    • %λΦ#@!Ω
  • ON6URE
    • on the road ...
    • collaborations ...

Country/region

  • Belgium EUR €
  • Germany EUR €
  • Italy EUR €
  • Sweden EUR €
  • Austria EUR €
  • Belgium EUR €
  • Bulgaria EUR €
  • Canada EUR €
  • Croatia EUR €
  • Czechia EUR €
  • Denmark EUR €
  • Estonia EUR €
  • Finland EUR €
  • France EUR €
  • Germany EUR €
  • Greece EUR €
  • Hungary EUR €
  • Ireland EUR €
  • Italy EUR €
  • Latvia EUR €
  • Lithuania EUR €
  • Luxembourg EUR €
  • Netherlands EUR €
  • Poland EUR €
  • Portugal EUR €
  • Romania EUR €
  • Slovakia EUR €
  • Slovenia EUR €
  • Spain EUR €
  • Sweden EUR €
  • Switzerland EUR €
  • United Kingdom EUR €
  • United States EUR €
  • YouTube
RF.Guru Logo
  • New
  • Hot
  • HotSpot
    • VHF
    • UHF
  • Repeater
    • ON0ORA
  • BalUn/UnUn
    • Balun
    • Unun
  • Isolators
    • Line Isolators
    • Surge Protection
  • Filters
    • VHF-UHF Filter
    • Line Filters
  • Antenna
    • HF Active RX Antenna
    • HF End Fed Wire Antenna
    • HF Verticals - V-Dipoles
    • HF Rigid Loops
    • HF Doublets - Inverted Vs
    • UHF Antenna
    • VHF Antenna
    • Dualband VHF-UHF
    • Grounding
    • Masts
    • Guy Ropes & Accessories
    • GPS Antenna
    • Mobile Antenna
    • Handheld Antenna
    • ISM Antenna 433/868
    • Antenna Tools
    • Anti-Corrosion Lubricants
    • Dummy Load
  • Coax
    • Coaxial Seal
    • Coax Connectors
    • Panel Mount Connectors
    • Coax Adaptors
    • Coax Tools
    • Coax Cable
    • Coax Surge protection
    • Jumper - Patch cable
  • 13.8 V
    • DC-DC
    • AC-DC
    • Powerpole
    • 13.8 V Cable
  • PA
    • VHF Power Amplifiers
    • UHF Power Amplifiers
  • Parts
    • Ferrite
    • Pi
    • Routers
  • PCB
  • SDR
  • APRS
  • KB
    • Product Whitepapers
    • Knowledge Base
    • Transmit Antennas
    • Baluns and Ununs
    • Receive Antennas & Arrays
    • Technical Deep Dives
    • Debunking Myths
    • Transmission lines
    • Radio Interference
    • Grounding and safety
    • Ham Radio 101
    • Calculators
    • Ham Florida Man
    • %λΦ#@!Ω
  • ON6URE
    • on the road ...
    • collaborations ...
Cart

Making Sense of Antenna Analyzer Readings

Almost every ham today owns an antenna analyzer. These handy tools display the complex impedance of your antenna system. But for many, the numbers — Z, R, X, +j, –j — are still mysterious. Let’s break them down in practical terms, so you can read your analyzer like a pro.

Related reading:
Why Inverted-L antennas beat ground verticals on the low bands
EFOC29: practical tips to tame 80 m & 30 m SWR
Why EFOC29 outperforms EFHW8010 & EFLW37 in multiband use

What Does Z Really Mean?

The analyzer shows the impedance Z, which is a combination of resistance (R) and reactance (X). Ideally, you want your antenna feedpoint to be as close as possible to 50 Ω purely resistive (R = 50, X = 0). That’s the sweet spot for most radios and coax.

Antennas rarely land exactly on 50 Ω. That’s where matching systems enter:

  • Core transformer (multiband): e.g., 49:1 or 4:1 to bring extreme impedances into a manageable range.
  • Transmission-line transformer (monoband): a chosen section of coax/ladderline (¼-wave, ½-wave, 1⁄12-wave tricks) to nudge Z with very low loss.

Important: these are not neutral adapters. They become part of the antenna system. They introduce R and can alter X by their very nature (conductor loss, core loss, parasitics).

Some commercial designs add parts (e.g., a capacitor in parallel with the transformer) to make the feedpoint look “prettier” to the radio. That doesn’t improve how the antenna radiates — it just hides real behavior. At RF.Guru we avoid such cosmetics. We prefer pure antennas, pure transformers. If you need extra range, use a proper transmatch (tuner) rather than masking physics.

Understanding X: The Reactance Part

X tells you if your system appears inductive or capacitive at that frequency:

  • +j (positive X): inductive appearance — often below the resonant point, but sign can flip around standing-wave dips due to reflections.
  • –j (negative X): capacitive appearance — often above resonance, with the same caveat about sign flips near dips.

±j is not a strict “too long / too short” detector. Reflections along the line (where the tuner sits, line length, chokes) can show +j or –j even when radiator length isn’t the culprit.

What Values Are Reasonable?

Reactance is normal. The real question is whether your system (transformer/line/tuner) can work efficiently with it:

  • |X| < 50 Ω: practically invisible; often inside an internal tuner’s range.
  • |X| = 50–150 Ω: routine for modern tuners; SWR rises but remains easy.
  • |X| ≥ 200 Ω: still workable. With good coax, even ~5:1 SWR typically adds < 1 dB extra line loss across 20–30 m runs when matched properly.
How much loss does 5:1 SWR really add?
  • Key point: With a decent low-loss HF coax (10–13 mm foam PE), matched loss around 14 MHz is typically about ~0.9 dB per 30 m (indicative).
  • Tuner at the shack: the line carries standing waves. Expect a modest increase over the matched loss. In practice for ~30 m, total line loss ≈ 1.0–1.2 dB at 5:1 SWR — i.e., < 1 dB extra compared to 1:1.
  • Tuner at the feedpoint: the line is re-matched; you’re back near the matched-loss figure (≈ 0.9 dB / 30 m in this example).
  • When does it get ugly? Very long runs or lossy/undersized coax. Keep lines reasonable and use quality cable; then even 3–5:1 is not catastrophic.

These are practical, conservative rules of thumb — the exact number depends on cable spec, length, and where the tuner sits.

Practical Takeaways

  • Read R and X together; SWR alone hides the cause.
  • Transformers and stubs become part of the antenna; they shape R and X — they are not neutral dongles.
  • ±j near dips is normal; don’t chase “zero X” dogmatically.
  • There are no perfect antennas — only in textbooks.

Mini-FAQ

  • Why does my analyzer show –j? — Capacitive appearance. Often means resonance is above your frequency — but reflections can also produce –j around dips.
  • Is a little reactance bad? — No. Tuners comfortably handle ±100 Ω. With good coax and sensible lengths, even 3–5:1 keeps total line loss low.
  • Are transformers just adapters? — No. They add R and can alter X. We avoid “masking” parts (e.g., parallel capacitors) that only make Z look pretty to the rig.

Interested in more technical content? Subscribe to our updates for deep-dive RF articles and lab notes.

Questions or experiences to share? Feel free to contact RF.Guru.

Written by Joeri Van Dooren, ON6URE – RF engineer, antenna designer, and founder of RF.Guru, specializing in high-performance HF/VHF antennas and RF components.

 

Subscribe here to receive updates on our latest product launches

  • YouTube
Payment methods
  • Bancontact
  • iDEAL
  • Maestro
  • Mastercard
  • PayPal
  • Visa
© 2025, RF Guru Powered by Shopify
  • Refund policy
  • Privacy policy
  • Terms of service
  • Contact information
  • News
  • Guru's Lab
  • Press
  • DXpeditions
  • Fairs & Exhibitions
  • Choosing a selection results in a full page refresh.
  • Opens in a new window.
Purchase options
Select a purchase option to pre order this product
Countdown header
Countdown message


DAYS
:
HRS
:
MINS
:
SECS