Calculators for operating and the workshop

Works both ways. Six characters describe a square of about 4.6 × 5.8 km.

Great circle over the sphere. For the rotator, the azimuth from A to B is what counts.

Free-space wavelength times velocity factor. For bare wire the factor is usually about 0.95, a little less for insulated wire.

From cable type and frequency, instead of hunting for the number in the datasheet. The values are rounded guide figures.

Use in the power budget

One value is enough, the others follow: either the SWR or forward and reflected power. Mismatch loss means what the mismatch costs you on top in the cable. Where SWR comes from and how to get rid of it is shown in the Smith chart.

What's left of the transmit power after cable and antenna. Take the loss from the cable loss calculator or from your datasheet.

One value is enough. On HF, S9 is 50 µV into 50 Ω, so −73 dBm. One S-unit is 6 dB, above that you count in dB over S9.

Far-field estimate against the limits of the 26. BImSchV (German EMF exposure ordinance) for the general public. It doesn't replace a BEMFV notification, for that there's the BEMFV assistant.

Enter two values and the third is worked out. It always calculates the field you haven't touched for the longest.

Single-layer solenoid after Wheeler. Accurate enough for matching networks and common-mode chokes, as long as the coil is longer than half its diameter.

Bands from left to right, starting with the one further from the edge.

Or the other way round: type in the marking of an SMD resistor or look up a value.

How long the battery lasts on air. Most of the time you're listening, so receive current often counts more than transmit current. A net with lots of listening comes to five to ten percent transmit time, FT8 running continuously to half.

Twelve volts forgive nothing: two metres of cable that's too thin, and the transceiver sags on transmit. The length is one way, the page works out there and back itself.