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: …
Understanding how antenna mismatch can damage a transmitter
Nov 1, 2023 · Antenna impedance is largely due to radiation resistance: a center fed half wavelength dipole has a radiation resistance of about 73 ohms. Resistance due to heat loss is negligible, and I …
Antenna tuning confusion - help! - Amateur Radio Stack Exchange
Aug 21, 2023 · A dipole antenna in free space ( no ground effects like capacitance or wire resistance) is 73 ohms. So if you had a dipole, @ a specific frequency, terminated into a 1/2 wavelength (electrical) …
What would be the typical received power of an "S9" signal?
The Wikipedia S Meter article cites: IARU Region 1 Technical Recommendation R.1 defines S9 for the HF bands to be a receiver input power of -73 dBm. This is a level of 50 microvolts at the receiver's …
Dipole increased CM current using choke balun - Amateur Radio Stack ...
Aug 23, 2019 · I've read that an inverted vee lowers the 73 ohm dipole impedance closer to the 50-ohm coax impedance but connecting a coax unbalances the antenna, so I wanted also to test using a …
Coaxial Folded Dipole Antenna Matching Impedance
Apr 22, 2015 · The site above depicts a regular dipole, with a simple matching system. First, a bit about dipole impedance. The impedance of a dipole is 73 Ohms at resonance, but away from the resonant …
Newest 'direwolf' Questions - Amateur Radio Stack Exchange
Oct 24, 2023 · Dire Wolf is a software "soundcard" AX.25 packet modem/TNC and APRS encoder/decoder. It can be used stand-alone to observe APRS traffic, as a tracker, digipeater, …
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 …
What was the origin of the Morse code abbreviations "hi" and "es"?
Dec 6, 2017 · Many Morse abbreviations and conventions come from before the days of radio, and we are relative latecomers to the game compared to the telegraphy guys. For this question, I found an …