Why do hams often conclude messages with "73"?
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. …
CW: when I supposed to send "E E"? - Amateur Radio Stack Exchange
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: …
What's the difference between saying “CQ” or “QRZ” in a contest?
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 …
How does one read a ferrite datasheet? - Amateur Radio Stack Exchange
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 …
How to estimate a dipole feedpoint impedance? - Amateur Radio Stack ...
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 …
Adding a choke to the feed point
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 …
baofeng - Squelch breaks but no sound - Amateur Radio Stack Exchange
Nov 10, 2024 · Otherwise, so you don't get frustrated just searching for frequencies, go to radioreference.com and look for amateur radio frequencies and repeaters near you. That will give …
What is dB (μV/m), and what are its applications?
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 …
united states - Are we allowed to use ISM bands for broadcast radio ...
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 …
Impedance Matching Different Feedlines - Amateur Radio Stack …
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).