Talk:Longwave

Royal Navy Subs

That wasn't the best wording on my part, sorry! User:Pegasus33 —Preceding undated comment added 04:26, 28 November 2009 (UTC).

Royal Navy subs

...monitoring 198 kHz. This claim, I think, needs qualifying with an "allegedly" or two. See The Today programme. Don't know -- seems to me like an adroit terrorist group could provoke a nuclear holocaust simply by taking out Droitwich (or Daventry?). –Hajor 20:41, 18 May 2004 (UTC)

I am also sceptical of the usefulness of this approach during peacetime, because subs have two-way VLF radio communication. In a crisis, when subs need to maintain complete radio silence, the British authorities could set up military exclusion zones around the three transmitters (Droitwich, Burghead and Westerglen) and such an approach might be more likely. (I suspect Burghead and Westerglen would be switched off in such a situation - subs probably have better receivers than the average Scottish household!). Rugxulo 22:11, 19 January 2006 (UTC)

Canada

I don't know that Industry Canada has allowed "LowFER" in Canada - can anyone find a cite for this? I'll have to check the IC Web site, maybe it's there...--Wtshymanski 13:32, 3 Jun 2005 (UTC)

Defunct long wave broadcasts?

I seem to recall reading an old issue of Practical Wireless from the 1970s which listed long wave broadcasts from Central Asia that were well into the 300's of kHz. Did these broadcasts exist? If anyone has firm information it would be an interesting addition to the article. Rugxulo 22:11, 19 January 2006 (UTC)

In light of this article

http://www.eurekalert.org/pub_releases/2006-02/su-rgf021706.php someone might want to re-evaluate the statement in the first paragraph of this article about how "longwave signals do not reflect or refract using the ionosphere."

The linked article says "Scientists detect these localized disturbances with VLF radio waves propagating along the Earth's surface. The ionosphere, like a metal, is a good electrical conductor. It acts as a guide for radio waves. That's why the Earth's curvature is no barrier, as VLF radio waves bounce off the ionosphere and can propagate to long distances around the globe, in the so-called Earth-ionosphere wave guide."

I realize that most lowfer xmissions use groundwave prop, but why would signals longer in wavelength than HF not also reflect from the ionosphere?

Relation to LF and MF articles

I've attempted to clarify the relationship between this article, and the LF and MF articles. The situation is still not very good, however; for example, information on longwave amateur bands is in LF, whereas information on LF commercial stations is in longwave. Some kind of merger seems to be in order, but I don't know the best way to handle that, given that the bands don't exactly match. — Johan the Ghost _seance 10:25, 11 May 2006 (UTC)

Now general information about LF (30-300 kHz) is in Low frequency and information specifically about LF broadcasting is in Longwave. Sv1xv (talk) 18:46, 1 March 2008 (UTC)

Clarkestown at night

This article claims that RTÉ off Clarkestown decreases its power at night. Now, as far as I can tell and remember (I live fairly close to the mast), in its Atlantic 252 days, Clarkestown operated 100kW daytime and 500kW nighttime. The station engineer I talked to also said the Radio Algeria transmitter went off-air over night. Obviously, even at the suggested power here, I'm not gonna be able to check the Radio Algeria transmissions without some very, very impressive sheilding :p There were reports back in the early 1990s of it being received in Brazil at night, which would suggest it had a clear channel.

Also, I've since been told that RTÉ now operate it at max. 300kW for simple cost saving reasons - they don't need a music quality signal across the entire UK; however would have thought that its still 100 day, 300 night. The site can actually operate at 600 but has no ITU clearance for such. --Kiand 03:12, 27 June 2006 (UTC)

The Irish allocation is for 500Kw daytime and 100 Kw night (Clarkestown can theoretically operate at 600Kw but as far as Im aware never actually has). The reason for this is that Longwave (and Mediumwave) signals travel further distances at night (due to ionospheric reflections) leading to increaced interference problems with other countries. In order to mitigate this (somewhat) it is common practive (particularly for larger stations) to run on reduced power at night.

During the odd breakdown at Clarkestown Algeria makes it quite well into Ireland (especially along the South coast) many people mistake it for a French station (since Algeria has two official languages French and Arabic) Finland also has an allocation for 1500Kw on 252 but has never used any more than 100Kw and in recent years hasnt used it at all. 87.112.28.7 13:22, 4 March 2007 (UTC)

Disambig

There needs to be a disambigulation page to differentiate between radio waves and other uses of "short wave" and "long wave" (such as those terms in Meteorology).

Longwave simulcasts in the US

I've heard numerous AM stations simulcast in the LW band inside the US. This seems to contradict the claim that there is no LW broadcast band.

A very late reply to that August 2007 comment but please amplify. It's possible what you're hearing is an image of a normal AM broadcast band transmitter; if you notice a consistent pattern where local AM transmitters show up 455 kHz lower on your LF receiver, I suspect this is the case. Other, more complex sources of images can occur especially if two or more transmitters produce a difference frequency in the LF band - but then you'd hear both of them interfering. A good check on this is to put a low-pass filter between the antenna and receiver; even a few extra dB of rejection of the AM broadcast band may make the images go away. --Wtshymanski (talk) 18:55, 1 March 2008 (UTC)

Please don't delete other people's comments, just add your own. Thank you. Sv1xv (talk) 20:16, 1 March 2008 (UTC)

Band Propagation

Article says: Instead, the D-layer of the ionosphere and the surface of the earth serve as a waveguide directing the signal[citation needed].

The following page describes in verbal and graphic way how the ionosphere and the earth's surface act as waveguides for longwave transmissions. http://www.weather.nps.navy.mil/~psguest/EMEO_online/module2/module_2_6.html

I am not sure if it's valid as a citation hence adding it here. I searched elsewhere with little success as how the ionosphere affects longwave radiation.

See also http://books.google.com/books?id=Xo5VxMTCz2UC&pg=PA1621&lpg=PA1621&dq=longwave+radio+ionosphere&source=web&ots=mociqIWSYk&sig=UVhWokRUm0OS5fzoSc9mFSmARaY&hl=en

193.120.148.177 (talk) 20:47, 21 March 2008 (UTC)

Frequency range

Why the ludicrous frequency range of 12 kHz to 1MHz? No one today used the term longwave for this band?Martin Hogbin (talk) 12:39, 6 August 2008 (UTC)

No, it is obviously wrong and the reference cited is irrelevant. Currently we call Low frequency the range 30-300 kHz and the term Longwave is used only by broadcasters.

Sv1xv (talk) 12:47, 6 August 2008 (UTC)

I've fixed this. I got a bit carried away and fixed a whole load of other stuff too.--Harumphy (talk) 15:23, 6 August 2008 (UTC)

Would you mind if I put the paragraph "Historically, the whole radio spectrum... allocated specifically for broadcasting" in a footnote?.

Sv1xv (talk) 16:42, 6 August 2008 (UTC)

Fine with me. Not that I am a regular here.Martin Hogbin (talk) 17:21, 6 August 2008 (UTC)

Longwave, long-wave, or long wave

I think this article should be called 'Long wave', or better still 'Long wave radio broadcasting band'.--Harumphy (talk) 15:23, 6 August 2008 (UTC)

"Longwave" is often a single word when applied to radios. Also, as a single word, it is then consistent with "shortwave".

More importantly, though, having been on Wikipedia for three years (since November 2005), you should know by now that cut-and-paste moves like the one you performed on August 16, 2008 [1][2] are against Wikipedia policy and never acceptable; it just creates work for administrators who have to merge the page histories back together (as I've done). Use the "move" tab at the top of the page instead, or if unable to do so because both pages have history, file a request at Wikipedia:Requested moves.

—Lowellian (reply) 04:00, 12 September 2008 (UTC)

Having been on Wikipedia for three years, I've forgotten most of rules I ever knew. Just as well, because in that time most of them have changed anyway. I tried the page move, but it wouldn't work because of an existing redirect. I didn't know any other way of solving the problem.

According to Chamber's 20th Century Dictionary, long-wave and short-wave (when applied to radios) are hyphenated. Inconsistently, it has "medium waves" (plural) without a hyphen. In all three cases, they are *not* single words. Is there an authoritative source to suggest they are single words? --Harumphy (talk) 13:38, 12 September 2008 (UTC)

Let me clarify something first: the main reason I got involved here was in order to merge two split page histories due to a cut-and-paste move. I'm not actually that interested in the name of the page.

There are three possible forms:

1. single-word "longwave"
2. hyphenated "long-wave"
3. two-word "long wave"

The third form, "long wave", is definitely not right; as a compound modifier (which see), it requires at least a hyphen.

Both the single-word and hyphenated forms, however, are correct. It's just one of those examples of variant spellings (is it "dwarfs" or "dwarves"? "indexes" or indices"? "judgment" or "judgement"?).

The Longwave Club of America ([3]) uses "longwave." A couple more examples:

• "[...] the National Bureau of Standards (predecessor to NIST) began broadcasting a longwave radio signal from its station KK2XEI [...]" --[4] National Institute of Standards and Technology
• "[...] until the arrival of shortwave radio, which was faster and cheaper than conventional longwave radio." --[5] National Aeronautics and Space Administration

We should seek consistency here: either have both "short-wave" and "long-wave" or both "shortwave" and "longwave". These are all descriptors of frequency; other "compound" frequency ranges like "microwave" and "ultraviolet" are more commonly seen in single-word rather than hyphenated form.

—Lowellian (reply) 16:01, 12 September 2008 (UTC)

Purpose

This article needs information on the purpose of long wave radio, e.g. why it is preferred over MW, why it should be used when long antenna setups are required, etc. -Rolypolyman (talk) 02:22, 2 October 2008 (UTC)

As far as I know the main reason why longwave radio was introduced for commercial radio is that the medium wave band was overcrowded before FM radio became common. It also has a longer daytime range than MW. For military applications longwave radio also has other advantages, e.g. that it goes deeper into water, which is useful for communication with submarines. Also the waves are mostly propagated through the ground and not through the air, so it can be used to communicate with underground bases. --MrBurns (talk) 22:32, 13 September 2018 (UTC)

Photo caption

I added a photo of an old-style radio dial purely as art. Someone has added a caption which I feel takes the image too literally and is inappropriate. I propose to revert it. Comments? --Harumphy (talk) 19:13, 17 May 2009 (UTC)

No comments received, so I've done it. --Harumphy (talk) 18:03, 19 May 2009 (UTC)

List of longwave transmitters

Please expand this list and add coordinates of transmission sites. —Preceding unsigned comment added by 91.46.217.2 (talk) 14:51, 15 January 2010 (UTC)

This table requires notes at the bottom explaining what the headers are about. I refer specifically to the header for antennas, are they the transmitting antennas or recommended receiving antennas?1archie99 (talk) 00:45, 11 December 2012 (UTC)

Yafran

Was there ever a longwave broadcasting transmitter in Yafran or elsewhere in Libya? — Preceding unsigned comment added by 91.46.158.98 (talk) 17:34, 11 September 2012 (UTC)

Disadvantages to Long-waveDadadaddyo (talk) 21:06, 17 July 2013 (UTC)

As a teenager in America, back in the 1960's, I wondered why with all its advantages there were no civilian broadcast on long-wave in the US and, as far as my research went, never had been. I remember reading that the big disadvantage of long-wave was that lightning almost anywhere on the globe caused static and since there are thunderstorms around the equator at pretty much any moment it was not suitable for broadcasting music (this was long before the days of talk radio). I had a multi-band receiver and I remember scanning the long-wave frequencies on a number of occasions and always picking up lighting type static even when I got none on medium wave (550-1600kHz). Could someone with more expertise address this and any other disadvantages to long-wave?

Long wave, because of the long wavelength, needs impractically large antennas to broadcast with any reasonable efficiency. The tallest ever man-made structure before the Burj Khalifa was a longwave transmitter: Warsaw radio mast. Its ground wave range is also relatively long compared to medium wave, which means that the transmissions will reach out over a much wider area (1000 km is not unusual). That may sound like an advantage, but at such low frequencies, bandwidth is at a premium, so the longwave band has to be rather small (it's just over 100 kHz wide in Europe). Combine those two effects, and and what happens is that a single medium-powered transmitter will swamp a very large area, making that frequency unusable to anyone else, and taking away almost 10% of the available frequency space within that wide area. So the longwave band is good purely from a transmission effectiveness point of view (if you ignore lightning interference) but it doesn't work too well on a economical/commercial level. This is one of the reasons the FM band was moved from 50 MHz to its modern place after WW2: the higher frequencies are much more strongly localised to one area, so there is room for a lot more stations in a given space and stations can cater more easily to smaller, local audiences, which keeps costs down and attracts more people. A longwave transmitter for a single large city is silly, but for VHF it works. I think that in a way, paradoxically, what helped longwave survive in Europe is that almost nobody wanted to use it, and radio was always much more strongly regulated historically (generally only state broadcasters could get licences). So there was little competition for frequency space, and that probably kept it viable. CodeCat (talk) 22:25, 17 July 2013 (UTC)

Cessation of most Russian longwave transmissions

'In January 2014 Russia announced the imminent closure of most of its LW broadcasting stations'. – It happened on 9 January 2014 at '1 a.m.' (Moscow? time) according to the updated URL quoted at Note 8. Apparently one remains in service. — Preceding unsigned comment added by 2.25.168.232 (talk) 19:37, 12 January 2014 (UTC)

longwave radiation

The usage of Longwave radiation (edit | talk | history | protect | delete | links | watch | logs | views) is under discussion, see talk:Outgoing longwave radiation -- 65.94.169.222 (talk) 08:30, 3 August 2014 (UTC)

Carrier Frequencies

Long-wave carrier frequencies are exact multiples of 9 kHz; ranging from 153 to 279 kHz, except for a French language station Europe #1 in Germany. This station did keep to correctly spaced channels spacing for 4 months—only 7 years ago, and all Mongolian transmitters are spaced at 10 kHz.

I'm really not sure what most of this means. Does this "French language station Europe #1 in Germany" currently space its frequencies by something other than 9 kHz? What's the significance of "only 7 years ago"? No sources are linked to explain any of this. 108.171.128.174 (talk) 09:52, 22 December 2016 (UTC)

It means that this French-language station is not at a multiple of 9 kHz. CodeCat (talk) 14:48, 22 December 2016 (UTC)

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