Actions

Difference between revisions of "DXing Above 30 Mhz"

From The RadioReference Wiki
m (→‎Maps: updated link)
 
(36 intermediate revisions by 5 users not shown)
Line 1: Line 1:
−
Talk to most people about how far a VHF signal (above 30 Mhz) will travel, and most times, the answer will be 'line of sight'. However, as there sometimes is in nature, there's exceptions to the rule. Many phenomenon can cause a VHF and UHF signal to travel hundreds of miles or more. Events such as a stalled weather front to a meteor shower or even the solar wind can change things in the atmosphere and make a signal travel much further than normal.
+
Talk to most people about how far a VHF signal (above 30 Mhz) will travel, and most times, the answer will be 'line of sight'. However, as there sometimes is in nature, there's exceptions to the rule. Many phenomenon can allow VHF and UHF transmissions to travel hundreds of miles or more. Events such as stalled weather fronts, meteor showers and solar weather events can temporarily change conditions in the atmosphere which allows transmissions to travel much further than normal.
  
−
The most common type of tropospheric ducting to impact scanner hobbyists and amateur radio operators results from a low-level temperature inversion. A low-level temperature inversion is a phenomena in which the temperature in the lower portion of the atmosphere, near the earth's surface, is considerably cooler than a layer further up in the atmosphere. This causes signals to be refracted thus resulting in a tunneling or ducting of the signals. Low-level temperature inversions can occur any time of the year but are often most dramatic (producing the most significant tropospheric ducting events) during the summer months. They are most often associated with surface high pressure which results in light near-surface winds allowing for radiative cooling affect. These events also commonly coincide with fog.  
+
One common type of atmospheric event that is of benefit to scanning scanner hobbyists and amateur radio operators is called "Tropospheric Ducting". Tropospheric Ducting occurs as a result of low-level temperature inversions. low-level temperature inversion is a phenomenon in which the temperature in the lower portion of the atmosphere, near the earth's surface, is considerably cooler than a layer farther up in the atmosphere. This causes signals to be refracted thus resulting in a tunneling or ducting of the signals. Low-level temperature inversions can occur any time of the year but are often most dramatic (producing the most significant tropospheric ducting events) during the summer months. They are most often associated with surface high pressure which results in light near-surface winds allowing for radiative cooling affect. These events also commonly coincide with fog.  
  
 
VHF, UHF and even 800 MHz and higher can be impacted quite significantly by these ducting events. One good example of very high frequencies being impacted is the anomalous propagation that plague the Doppler weather radar (WSR-88D) during the most extreme tropospheric ducting episodes.  
 
VHF, UHF and even 800 MHz and higher can be impacted quite significantly by these ducting events. One good example of very high frequencies being impacted is the anomalous propagation that plague the Doppler weather radar (WSR-88D) during the most extreme tropospheric ducting episodes.  
  
−
Hams (and folks involved in TV/FM DXing) have been studying this for years. Many of these phenomenon have been cataloged, but not are all well understood. If you are interested in a description of how a VHF signal (or above) can travel, take a look at this [http://en.wikipedia.org/wiki/TV/FM_DX article] on the WikiPedia site. Keep in mind that FM and TV broadcast, as well as ham frequencies, are found above 30 mhz. Techniques used in TV, FM and 2/432 Mhz DXing are applicable to DXing in the scanner bands.
+
Hams (and folks involved in TV/FM DXing) have been studying this for years. Many of these phenomenon have been cataloged, but not are all well understood. If you are interested in a description of how a VHF signal (or above) can travel, take a look at this [http://en.wikipedia.org/wiki/TV/FM_DX article] on the WikiPedia site. Keep in mind that FM and TV broadcasts, as well as ham frequencies, are found above 30 MHz. Techniques used in TV, FM and 144/220/432 Mhz DXing are applicable to DXing in the scanner bands.
  
−
The links below are not intended to be comprehensive, but rather be a starting point for getting more information. Additional links with descriptions and maps are always welcome.
+
The links below are not intended to be exhaustive, but rather be a starting point for getting more information. Additional links with descriptions and maps are always welcome.
  
−
The RR forum for discussing VHF/UHF skip can be found [http://www.radioreference.com/forums/forumdisplay.php?f=96 here]
+
The RR forum for discussing VHF/UHF skip can be found at the {{Forum|skip-tropospheric-ducting-forum.96|Skip and Tropospheric Ducting}}
  
−
==Maps==  
+
==Applications and Databases==
 +
; Applications
 +
* [https://www.df8ry.de/htmlen/csvub/%F0%9F%92%BEdownload.htm CSVUserlist Browser]
 +
* [http://www.freqmgrsuite.com/ Frequency Manager Suite]
 +
 
 +
; Databases
 +
* [https://www.fcc.gov/media/radio/radio-lists Broadcast AM and FM Radio Reports and Lists]
 +
* [https://www.fcc.gov/media/radio/fm-query#block-menu-block-4 FCC FM Query Broadcast Station Search]
 +
* [https://www.fcc.gov/media/television/tv-query FCC TV Query Broadcast Station Search]
 +
* [https://www.fmlist.org/ul_login.php?sprache=en FMList]
 +
* [https://fmscan.org/index.php?la=en FMScan]
 +
* [http://lpfmdatabase.weebly.com/ LPFM Database]
 +
 
 +
==Equipment==
 +
* [https://tinyurl.com/y7eellwj Antennas Direct]
 +
* [https://fmradiodx.wordpress.com/sections/radio-reviews/ FM Radio DX Radio Reviews]
 +
* [http://www.fmtunerinfo.com/ FM Tuner Information Center]
 +
* [http://www.godarusa.com/id84.html Godar DXR-1000 AM/SW/FM Antenna]
 +
* [[Live Tunable Receivers]]
 +
* [https://www.ccrane.com/item/ant_fm_fmr2/101106/fm_reflect-2_dipole_antenna FM Reflect 2 Dipole Antenna]  C Crane Co.
 +
* [[Software Defined Radios]]
 +
 
 +
==Maps==
 +
* [https://www.dxmaps.com/spots/map.php DXMaps]
 +
* [https://www.radio-locator.com/cgi-bin/finder?page=Y Radio Station Finder]
 +
* [http://tropo.f5len.org Tropospheric Propagation Forecast]
 +
* [https://rabbitears.info/tvdx/all_tuners TV Reception Map - rabbitears.info]
 +
* [http://vhf.dxview.org VHF Propagation Map]
 
* [http://www.dxinfocentre.com/tropo.html William Hepburn's Worldwide Tropospheric Ducting Forecasts]
 
* [http://www.dxinfocentre.com/tropo.html William Hepburn's Worldwide Tropospheric Ducting Forecasts]
−
* [http://www.vhfdx.info/spots/map.php DX Sherlock 2.3 - V-UHF QSO Real Time Maps]
 
−
* [http://www.mountainlake.k12.mn.us/ham/aprs/ VHF Propagation Maps]
 
−
* [http://www.radio-locator.com/cgi-bin/finder?page=Y Radio Station Finder]
 
−
* [http://www.fmscan.org/index.php?r=m FMScan.org]
 
−
* [http://www.spacew.com/www/realtime.php Near Real Time MUF maps]
 
−
 
−
==Technical Articles==
 
−
* [http://www.quercus.demon.co.uk/tropo.html M1BWR's Non-Ducting Tropo Inner Sanctum]
 
−
* [http://www.gooddx.net/ The DX Robot] Automatic real-time AURORA and E-skip warnings via email or mobile phone
 
−
* [http://www.kg0vl.com/ KG0VL VHF Aurora Radio Research]
 
−
* [http://home.swbell.net/pjdyer/index.html WA5IYX VHF Propagation Info]
 
  
 
==Other Propagation Links==
 
==Other Propagation Links==
−
* [[HF Propagation]]
+
* [http://ac6v.com/propagation.php AC6V Propagation Links]  
−
* [http://ac6v.com/propagation.htm AC6V Propagation Links]  
+
* [https://www.eham.net/propagation EHam Propagation Links]
−
* [http://www.eham.net/DX/propagation EHam Propagation Links]
 
−
* [http://www.theweatherprediction.com/habyhints/247/ Weather Radar Anomalous Propagation]
 
−
* [http://www.amfmdx.net/propagation/Es.html Mid-Latitude Sporadic-E (Es) - A Review]
 
−
* [http://www.sv2agw.com/ham/vista_dxrobot.htm DX Robot VHF Propagation] Sidebar utility for Vista
 
 
* [[SNOTEL]] - indicator of VHF Low Band Skip
 
* [[SNOTEL]] - indicator of VHF Low Band Skip
 +
 +
==Technical Articles==
 +
* [http://www.kg0vl.com/?page_id=5 KG0VL VHF Aurora Radio Research]
  
 
==TV/FM DX Links==
 
==TV/FM DX Links==
−
* Also see our [[MW DXing and Broadcasting]] article for additional related links
+
* [https://www.dxcentralonline.com/ DX Central]
−
* [http://www.fcc.gov/mb/audio/fmq.html FCC FM Radio Database Query]
+
** [https://www.youtube.com/channel/UCVKn6FsYIsNjDorND2MJ2MA DX Central YouTube channel]
−
* [http://www.fmtunerinfo.com/ FM Tuner Information Center]
+
* [https://www.radioworld.com/news-and-business/fcc-tweaks-lpfm-technical-rules FCC Tweaks LPFM Technical Rules]
−
* [http://www.dxfm.com/ FM/TV DXing from Lexington Ky.]
+
* [https://fmradiodx.wordpress.com/ FM Radio DX]
−
* [http://www.odxa.on.ca/ Ontario DX Association]
+
* [https://band2dx.webs.com/ Long Distance FM Reception from Paul Hogan - Ireland]
−
* [http://www.radio.hobby.ru/ Russian Radio TV DX (in Russian)]
+
* [http://dxworld.com/tvfmlog.html TV FM Skip log]
−
* [http://www.skywaves.info/ Skywaves (UK)]  
+
* [http://www.wtfda.org/ Worldwide TV/FM DX Association]
 +
* [http://www.anarc.org/wtfda/propagation.htm WTFDA Propagation Page] old but still lots of useful information. Written by well known author and DXLD owner Glenn Hauser
  
−
; Worldwide TV FM DX Association (WTFDA)
+
==Mailing Lists/Facebook==
−
* [http://www.wtfda.org/ Worldwide TV/FM DX Association home (new)]
+
* [http://mailman.qth.net/mailman/listinfo/amfmtvdx AMFMTVDX]  qth.net
−
* [http://www.anarc.org/wtfda/propagation.htm WTFDA Propagation Page] old but still lots of useful information. Written by well known author and DXLD owner Glenn Hauser
+
* [https://groups.io/g/odxa Ontario DX Association] groups.io
−
* [http://www.wtfda.org/index.php?option=com_weblinks&Itemid=23 WTFDA links page (new site)]
+
* [https://www.facebook.com/groups/WTFDA WTFDA Facebook page]
 +
* [https://groups.google.com/forum/#!forum/wtfda WTFDA on Google Groups]
  
−
==Mailing Lists==
 
−
* [http://mailman.qth.net/mailman/listinfo/amfmtvdx AMFMTVDX qth.net reflector]
 
−
* [http://groups.yahoo.com/group/dx-tv/ DX-TV]
 
−
* [http://groups.yahoo.com/group/odxa/ Ontario DX Association]
 
−
* [http://uk.groups.yahoo.com/group/skywaves/ Skywaves (UK Group}]
 
−
* [http://groups.yahoo.com/group/webreceivers/ WebReceivers]
 
 
[[Category:Propagation Links]]
 
[[Category:Propagation Links]]
 
[[Category:Broadcasting]]
 
[[Category:Broadcasting]]

Latest revision as of 10:22, 26 March 2023

Talk to most people about how far a VHF signal (above 30 Mhz) will travel, and most times, the answer will be 'line of sight'. However, as there sometimes is in nature, there's exceptions to the rule. Many phenomenon can allow VHF and UHF transmissions to travel hundreds of miles or more. Events such as stalled weather fronts, meteor showers and solar weather events can temporarily change conditions in the atmosphere which allows transmissions to travel much further than normal.

One common type of atmospheric event that is of benefit to scanning scanner hobbyists and amateur radio operators is called "Tropospheric Ducting". Tropospheric Ducting occurs as a result of low-level temperature inversions. low-level temperature inversion is a phenomenon in which the temperature in the lower portion of the atmosphere, near the earth's surface, is considerably cooler than a layer farther up in the atmosphere. This causes signals to be refracted thus resulting in a tunneling or ducting of the signals. Low-level temperature inversions can occur any time of the year but are often most dramatic (producing the most significant tropospheric ducting events) during the summer months. They are most often associated with surface high pressure which results in light near-surface winds allowing for radiative cooling affect. These events also commonly coincide with fog.

VHF, UHF and even 800 MHz and higher can be impacted quite significantly by these ducting events. One good example of very high frequencies being impacted is the anomalous propagation that plague the Doppler weather radar (WSR-88D) during the most extreme tropospheric ducting episodes.

Hams (and folks involved in TV/FM DXing) have been studying this for years. Many of these phenomenon have been cataloged, but not are all well understood. If you are interested in a description of how a VHF signal (or above) can travel, take a look at this article on the WikiPedia site. Keep in mind that FM and TV broadcasts, as well as ham frequencies, are found above 30 MHz. Techniques used in TV, FM and 144/220/432 Mhz DXing are applicable to DXing in the scanner bands.

The links below are not intended to be exhaustive, but rather be a starting point for getting more information. Additional links with descriptions and maps are always welcome.

The RR forum for discussing VHF/UHF skip can be found at the Skip and Tropospheric Ducting Forum

Applications and Databases

Applications
Databases

Equipment

Maps

Other Propagation Links

Technical Articles

TV/FM DX Links

Mailing Lists/Facebook

Retrieved from "https://wiki.radioreference.com/index.php?title=DXing_Above_30_Mhz&oldid=311021"