Amateur Radio Antenna & Feedline Math: Wavelengths, Dipole & Vertical Lengths, SWR & Mismatch Loss, Coax Loss, ERP and Logbook Statistics
Do the maths behind a radio station. You will convert frequency to wavelength, cut dipoles and verticals with a velocity factor, compute reflection coefficient, SWR and mismatch loss, estimate coax loss for fictional cable types, find the power reaching the antenna and the effective radiated power, convert grid locators with a lookup table and analyse your contacts log, with every cell checked as you go.
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About this course
In this course you work through the numbers behind a radio station with a spreadsheet, using one fictional club member from start to finish. You turn frequencies into wavelengths, cut half-wave dipoles and quarter-wave verticals with an end-effect factor and trim a dipole to its target frequency. You compute the reflection coefficient, SWR and mismatch loss in decibels, look up fictional cable losses in a two-way table and work out the watts that reach the antenna. Then you build a power budget with dBm, dBi and dBd and the effective radiated power, decode grid locators with a letter table, measure distances with the haversine formula and summarise a logbook with a chart.
Lessons
- Frequency and Wavelength: λ = c ÷ f, Half Waves and a Practice Channel Plan Pro
- Antenna Lengths: Half-Wave Dipoles, Quarter-Wave Verticals, End Effect and Trimming Pro
- SWR from the Load: Reflection Coefficient, ABS and the Meter Reading Backwards Pro
- Mismatch Loss: Reflected Power, Decibels with LOG10 and Watts Accepted Pro
- Feedline Loss: dB per 100 m from a Cable Table, Connectors and the Watts That Arrive Pro
- Power Budget: Watts to dBm, dBi vs dBd, Net Gain and Effective Radiated Power Pro
- Grid Locators: Letters and Digits to Longitude and Latitude, and the Distance Between Stations Pro
- Capstone: Logbook Statistics – Contacts per Band, Evening Openings, the Longest Contact and a Chart Pro