Coax loss & recommendation
Compare common 50-ohm cables for your frequency, length and power.
Selected cable-- dB
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| Cable | Total loss | At antenna | Delivered | Rating |
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23 calculators shown
Antenna & feedline 4 tools
Plan the RF path from radio to antenna
Antenna cutting length
Starting dimensions for common wire and vertical antennas.
Total starting length--
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Wavelength & coax stub
Free-space wavelength and physical cable stub length.
Physical coax stub--
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VSWR & return loss
Convert standing-wave ratio into reflected power and mismatch loss.
Return loss--
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RF & propagation 6 tools
Understand power, paths and coverage
RF power, EIRP & ERP
Allow for feedline loss and antenna gain.
Estimated EIRP--
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Watts & dBm converter
Convert RF power in either direction.
Converted power--
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Path loss & link budget
Ideal free-space loss and estimated received power.
Free-space path loss--
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Fresnel zone clearance
First Fresnel-zone radius at a point along a radio path.
First-zone radius--
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Radio horizon
Smooth-Earth line-of-sight estimate between two antennas.
Typical radio horizon--
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Maidenhead locator distance & bearing
Calculate the great-circle direction and distance between two 4- or 6-character grid locators.
Distance--
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Radio workshop 6 tools
Electronics, power and station wiring
Ohm's law
Calculate voltage, current, resistance and power.
Power--
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LC resonance
Find the resonant frequency of an inductor and capacitor.
Resonant frequency--
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Inductive & capacitive reactance
Compare XL and XC at a chosen frequency.
Inductive reactance--
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Battery runtime
Estimate operating time from capacity, load and duty cycle.
Estimated runtime--
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DC cable voltage drop
Estimate round-trip loss in station power wiring.
Voltage drop--
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Resistor voltage divider
Calculate unloaded or loaded divider output voltage.
Output voltage--
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More station tools 7 tools
Location, repeaters and practical adjustments
UK postcode to Maidenhead locator
Find the approximate postcode centre, locator, coordinates, national grid reference and Google Maps position.
Maidenhead locatorEnter a postcode
The lookup runs only when you press the button.
Open in Google MapsCoordinates to Maidenhead locator
Convert WGS84 latitude and longitude into a 6-character locator.
Maidenhead locator--
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Repeater input / output frequency
Apply a positive or negative repeater shift to a known frequency.
Repeater input--
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Forward & reflected power
Estimate reflected and delivered power from forward power and VSWR.
Reflected power--
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dB gain & loss chain
Add three gain or loss stages and calculate final RF power.
Final power--
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Antenna trim correction
Adjust an existing element length from its measured resonance to a target frequency.
New estimated length--
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UK repeater & gateway finder
Find nearby UK radio systems with distance and beam direction from your postcode.
Search from your postcode
Results include frequencies, modes, access information, keeper, locator and station details.
Use these calculators as practical starting points. Real installations vary with component tolerance, cable condition, connectors, temperature, antenna surroundings, terrain and measurement method. Check critical work with suitable test equipment.