Networking & Communications

Voltage across a 250 Ω HART / PLC current-loop resistor.

Starting length for a quarter-wave or half-wave element. Not a final cut length.

Convert antenna gain between isotropic (dBi) and dipole (dBd) references.

Convert between CIDR prefix length and a contiguous dotted-decimal IPv4 mask.

Convert RF power between watts and dBm (referenced to 1 mW).

Convert RF power between watts and dBW (referenced to 1 W).

Power dissipated in wiring, Ethernet PoE loops, or another resistive element.

Effective isotropic radiated power from TX power, feedline losses, and antenna gain.

Modeled fade margin from received power and receiver sensitivity.

Modeled optical receive power and margin from fiber, connector, and splice losses.

Modeled payload rate after a stated frame/protocol overhead. Not a universal Ethernet number.

Theoretical free-space path loss. Not a prediction of field performance.

First Fresnel-zone radius along a straight-line path. Does not analyse terrain.

Smallest IPv4 prefix that can hold the required number of hosts.

Check whether two IPv4 addresses belong to the same subnet.

Network, broadcast, mask, and usable host range from an IPv4 address and prefix or mask.

Min, max, average, median, and successive-sample jitter from ping-style timings.

Expected received power from a complete RF link. Optional fade margin when sensitivity is given.

How much of a link’s capacity is consumed by an observed rate.

Convert between voltage, current, and power for a DC, PoE, or unity-PF load.

Whether a packet fits a path MTU, and by how many bytes it exceeds it.

Solve for voltage, current, resistance, or power from any two of the four.

Loss count and ratio from transmitted and received packet counts.

Whether a PoE source budget covers connected PD loads. Not a PoE class lookup.

Geometric radio line-of-sight distance from two antenna heights. Estimate only.

Contextual reading of RSSI and SNR. Not a technology-specific pass/fail tool.

Compare two Ethernet interfaces for speed or duplex mismatch.

Theoretical time to move a payload at a link rate. Optional efficiency derates the rate.

Classify an IEEE 802.1Q VLAN identifier as usable or reserved.

Calculate voltage drop or IR drop from current and resistance.

Free-space wavelength from frequency.