Difference between revisions of "HF"
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== Online HF Receivers == | == Online HF Receivers == | ||
There are quite a few receivers online that you can listen to HF communications. Some of them even allow you to control the radio for limited times. Some others are set to a specific frequency on the HF band that usually has a lot of activity. | There are quite a few receivers online that you can listen to HF communications. Some of them even allow you to control the radio for limited times. Some others are set to a specific frequency on the HF band that usually has a lot of activity. | ||
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Revision as of 06:12, 19 July 2006
"HF" is an abbreviation for "High Frequency." See Spectrum.
High frequency communications occur in the 3-30 MHz band. Signals in this band can be refracted by the ionosphere allowing worldwide propagation. The distance varies depending on time of day, the solar cycle and current solar and geomagnetic activity, but in general the higher frequencies go further in daylight and the lower frequncies go further at night.
Many of the FAQs linked here are courtesy of DXing.Com from Universal Radio of Reynoldsburg Oh. and the Monitoring Times website.
Contents
AM (MW) Band
540-1700 kHz
- Intro to AM(MW) DXing
- See our SWL Broadcast page for clubs devoted to this topic
- Also check out the RadioIntel References page for more information
- Look for the topic 'MW (AM) & FM' for more links on the subject
HF Amateur Radio Bands
80 Meters (3.500-4.000 MHz)
60 Meters (see 60 Meter Frequently Asked Questions (via ARRL) for the five USB channels)
40 Meters (7.000-7.300 MHz)
30 Meters (10.100-10.150 MHz)
NOTE US Amateurs are limited to 200w PEP, and must use CW or digital modes (no voice). This is a shared band, and hams must avoid causing interference to other users. There is an encrypted RTTY station (assumed by many to be the US Navy) in the low portion of this band.
20 Meters (14.000-14.350 MHz)
17 Meters (18.068-18.168 MHz)
15 Meters (21.000-21.450 MHz)
12 Meters (24.890-24.990 MHz)
10 Meters (28.000-29.700 MHz)
Amateur Related and RF Safety websites
Here's a very comprehensive list of amateur nets, updated regularly, edited by John Norfolk
And for storm-related nets, see...
Some popular ham websites:
- US Navy
Citizen's Band
- See the Citizens Band page for frequencies and channels
- REACT
Short Wave Broadcast
What is short wave broadcasting? These FAQs will help explain it;
Some FAQs about the terminology you will hear used;
- AMANDX
- This site has many basic articles on antennas, propagation, schedules and much more. Highly recommended reading
- Commonly Used Modes
- Frequency Ranges and Uses
- Frequency vs.Wavelength
- Glossary of Terminology
- Receiver Dynamic Range
- Synchronous Modulation/Detection
- Terms and Abbreviations
- UTC and GMT
- Understanding Receiver Selectivity
- Understanding Receiver Sensitivity
- Understanding Specifications
- Take a look at the SWL Broadcast page for many related links
and there's other kinds of short wave broadcasting, too...
- Introduction to Pirate Radio
- Introduction to Clandestine Radio
- Numbers and Oddities
- Clandestine Radio Watch
Utility Monitoring
The best way to describe Utility (Ute) monitoring is to use negative logic; it excludes everything defined above. Not CB, Amateur nor Short Wave Broadcast. This includes, but is not limited to, aeronautical stations, digital signals (outside of the specified amateur bands), military, maritime, federal and other users. See our Utility Monitoring page for more information and links.
Miscellaneous
Online HF Receivers
There are quite a few receivers online that you can listen to HF communications. Some of them even allow you to control the radio for limited times. Some others are set to a specific frequency on the HF band that usually has a lot of activity.