Oct 25, 2013 · The usage of "73" for such a purpose comes from the Phillips Code, originally devised in the era of telegraphs to speed up transmission of common messages by mapping them to numbers. …

Jan 8, 2020 · I'm new to CW and one thing I couldn't figure out is when I supposed to send "E E". Let's say I'm calling CQ and somebody answers me. The QSO is almost over. Should it be ended like this: …

The best thing to do is to listen for a while, and notice which stations are being responded to. Sometimes operators will prematurely respond with their callsign, without waiting to hear if the other station has …

An ideal dipole, at resonance, will have an impedance around 73 ohms. A folded dipole, around 280 ohms. How can I calculate the impedances when not at resonance? Let's assume I have a span of …

For example, Fair-Rite's 73 material: What's a $\mu'_s$ and a $\mu''_s$? What do these numbers represent, and how can I use them in amateur radio? Do they allow me to predict inductance or …

Theoretically, (73 + j42.5)Ω. When the dipole is too short, its reactance will be capacitive. When it's too long, inductive. Since the exactly half-wave dipole has a slightly inductive reactance, shortening it …

Dec 13, 2024 · 1 I recently installed a vertical antenna and was surprised by the loud noise. I am thinking of adding a choke to the feed point, but is it sufficient to simply add one? Or should I adjust …

A folded dipole will increase this impedance to the square of the number of parallel elements (for the ultralite sr. with 3 parallel elements, I calculate 9 * 73 = 657 ohms impedance).

Dec 22, 2017 · A dB (µV/m) is a decibel relation for a sub-unit of V/m, which is appropriate for units of the e-field intensity of a radiated e-m wave existing between two physical points in space separated …

Sep 15, 2025 · ISM bands are unlicensed for Part 15 compliant devices, which include some communication devices, but broadcast audio or video programming, intended for the public, for …