From 14764d5034e9139985c30f8d6314bbacde98c5ff Mon Sep 17 00:00:00 2001 From: Tyler Perkins Date: Fri, 12 Nov 2021 14:30:01 -0500 Subject: [PATCH] Update for 12-11-21 14:30 --- tech/Modulation.wiki | 16 ++++++++++++++++ tech/frequency_range.wiki | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+) diff --git a/tech/Modulation.wiki b/tech/Modulation.wiki index ae64609..bea0ab8 100644 --- a/tech/Modulation.wiki +++ b/tech/Modulation.wiki @@ -29,6 +29,9 @@ signal is changed to encode information. The signal as a result will take up space both above and below the carrier, called Upper Side Band (USB) and Lower Side Band (LSB). +AM has a Peak Envelope Power. This is determined by the max power of the +transmitter, and the Mic gain. + === SSB === Bandwidth: 2-3khz (voice); 500-3000hz (digital) @@ -44,6 +47,9 @@ narrower portion of the signal, it is often used for long distance VHF and UHF Standards have formed around SSB, and wether to use USB or LSB on different frequencies. If < 10Mhz, LSB. Else if >= 10Mhz, USB. +SSB has a Peak Envelope Power. This is determined by the max power of the +transmitter, and the Mic gain. + === FM/PM === Bandwidth: 10-15khz (voice); 150khz (broadcast) @@ -52,4 +58,14 @@ Frequency Modulation (FM) and Phase Modulation (PM) are two similar types of modulation where the signal is encoded by changing either the frequency of the signal, or the phase of the signal. +Because FM/PM does not change in amplitude, the power output is fixed. +Therefore, the PEP is fixed as well. +== Overmodulation == + +Over modulation or splattering is when the signal is to heavily modulated, +making it use to much bandwidth. This is generally negative, and can often be +fixed by speaking softly, changing mic gain, or moving away from the mic. + +The sound it makes to the reciever is a 'breaking up' sound, where distortion +occours on voice peaks. diff --git a/tech/frequency_range.wiki b/tech/frequency_range.wiki index 442a478..8b9b1d2 100644 --- a/tech/frequency_range.wiki +++ b/tech/frequency_range.wiki @@ -27,3 +27,35 @@ A shorthand is WL = 300 / f Where f is in Mhz + +== Frequency to Wavelength == + +Below are the common wavelength and frequencies + +| Frequency (Mhz) | Wavelength | +---------------------------------------- +| HF/MF | HF/MF | +| 1.8 | 160m | +| 3.5 | 80m | +| 5 | 60m | +| 7 | 40m | +| 10 | 30m | +| 14 | 20m | +| 18 | 17m | +| 21 | 15m | +| 24 | 12m | +| 28 | 10m | +| VHF | VHF | +| 50 | 6m | +| 144 | 2m | +| 222 | 1.25m | +| UHF | UHF | +| 440 | 70cm | +| 902 | 33cm | +| 1240 | 23cm | +| 2300 | 13cm | + + + + +