In the US, I don't think there was any commercial LW broadcasting (but I could easily be wrong). US-market radios rarely had SW bands and almost never had LW unless they were general coverage receivers. For the most part, the few times I looked through the band it was largely navigation beacons.
I was rather surprised to see an LW band on a regular clock-radio when I visited the UK, though that was 25 years ago.
There has been no commercial broadcast radio on the longwave band in the US, that's correct. That's why radios featuring that band are rarer here, and usually confined only to enthusiast radios.
The WWVB time signal is technically inside the longwave band, at 60kHz.
I sincerely hope that if the remaining stations shut down, the band will become an amateur band. Existing 2200m and 630m are narrow, so allocating this entire range is something of a pipe dream, but it would be the best outcome.
(Not sure how 1750m LowFER would be handled; maybe just keep it on as an unlicensed exception?)
Marconi T or L antennas with capacitance hats and loading coils are well within amateur practice on 630m[1] and 2200m, and common from 40m/7MHz on down.
Not very efficient still; an ERP of 1W, as demanded by the 2200m band, can still take a lot of power on a less-than-ideal antenna. Similar story for 630m. (160m and up is usually not so bad, just that even a good Marconi on longwave is still too big for most people.)
But the current LowFER[3] regs limit the transmitter to 1W final stage input power, and a COMBINED feedline and antenna length of 15m. At least allowing amateurs to operate more here would allow more than just extremely low SNR modes like WSPR to be used at any real distance.
"Plus, an article in The Guardian in 2011 claimed that only a small number of spare valves were still available for the transmitter."
What a pathetic argument! When you read crap like this you know you're being told sop—an attempt to bamboozle the public with technicalities that don't really exist. Any commonly available high powered RF tetrode from an FM or TV station would do the job albeit with some (mostly mechanical) modifications to the transmitters. Also, it's a common practice to refurbish high power transmitting valves, there are companies that specialize in doing it.
I say that as someone who has been involved with high power broadcasting transmitters, in fact I was involved in building several FM broadcast transmitters from the ground up.
At only 198kHz—which is somewhere between one 1/500th and 1/1500th its normal operating frequency—any high power VHF transmitting tetrode would be just loafing along.
No doubt the way commerce works getting a one-off specialist job to do the conversion would be expensive (I wish I could do it, I'd quote half the price and still make a handsome profit).
If the BBC is so strapped for cash perhaps it could ask the Amateur Radio fraternity to mod the TXes for free as a public service. Then after the mods the service could recommence on half power to save costs.
Also, there are good strategic reasons why this transmitting infrastructure should be kept operational on these low longwave frequencies which I haven't got time to address here.
Suffice to say, I think this proposed closure is more a hatchet job by accountants than from any long-term strategic thinking by governments.
Damn shame governments only seem to listen to nanny goat advisors these days.
I agree it's 99% ridiculous, but to play the devil's advocate: modifications could require re-certifying the transmitter due to regulations, which might make them not financially worth it after the remaining correct tubes die. Especially since regulations governing something so boutique and relatively obscure haven't probably been updated much to make stuff like this easier. (I confess high ignorance to UK law.)
My first contact with English was listening to the Radio Canada International. Then I knew that I needed to learn it to receive news that only would be in newspapers 2 or 3 days later.
Now there are none stations that I can listen at night, and I miss it
As far as I know, the UK's nuclear submarine fleet used (or still uses?) the presence of a Radio 4 broadcast signal as evidence for the continued existence of the UK. Hopefully they have other means at this point!
> During the time following a perceived attack, a series of progressive checks are made by submarine crews leading up to the captain opening the letter. These include trying to listen for radio transmissions from various levels of Royal Navy and Ministry of Defense command using multiple methods, and most famous of all, listening for new radio broadcasts by BBC Radio channel four, and specifically new episodes of BBC Today. […]
LF, MF, and so on are bands, or frequency ranges. AM is a modulation technique. It, like FM and others, can be used on any band (although regulations can limit this).
It doesn't: There's a lot of non-AM/non-voice stuff on longwave, most notably various digital time beacons (WWVB in the US, DCF77 in Western Europe etc.)
In the US, I don't think there was any commercial LW broadcasting (but I could easily be wrong). US-market radios rarely had SW bands and almost never had LW unless they were general coverage receivers. For the most part, the few times I looked through the band it was largely navigation beacons.
I was rather surprised to see an LW band on a regular clock-radio when I visited the UK, though that was 25 years ago.
There has been no commercial broadcast radio on the longwave band in the US, that's correct. That's why radios featuring that band are rarer here, and usually confined only to enthusiast radios.
The WWVB time signal is technically inside the longwave band, at 60kHz.
I sincerely hope that if the remaining stations shut down, the band will become an amateur band. Existing 2200m and 630m are narrow, so allocating this entire range is something of a pipe dream, but it would be the best outcome.
(Not sure how 1750m LowFER would be handled; maybe just keep it on as an unlicensed exception?)
I think LW transmission antennas are too large to be built bu amateurs
Full verticals, dipoles, Yagis or logs, yes.
Marconi T or L antennas with capacitance hats and loading coils are well within amateur practice on 630m[1] and 2200m, and common from 40m/7MHz on down.
Not very efficient still; an ERP of 1W, as demanded by the 2200m band, can still take a lot of power on a less-than-ideal antenna. Similar story for 630m. (160m and up is usually not so bad, just that even a good Marconi on longwave is still too big for most people.)
But the current LowFER[3] regs limit the transmitter to 1W final stage input power, and a COMBINED feedline and antenna length of 15m. At least allowing amateurs to operate more here would allow more than just extremely low SNR modes like WSPR to be used at any real distance.
[1]https://www.hamsignal.com/blog/dog-days-and-the-marconi-t-an...
and https://vk6ysf.com/t_antenna_arrangment.htm
[2]https://en.wikipedia.org/wiki/2200-meter_band#International_...
[3]https://en.wikipedia.org/wiki/LowFER
"Plus, an article in The Guardian in 2011 claimed that only a small number of spare valves were still available for the transmitter."
What a pathetic argument! When you read crap like this you know you're being told sop—an attempt to bamboozle the public with technicalities that don't really exist. Any commonly available high powered RF tetrode from an FM or TV station would do the job albeit with some (mostly mechanical) modifications to the transmitters. Also, it's a common practice to refurbish high power transmitting valves, there are companies that specialize in doing it.
I say that as someone who has been involved with high power broadcasting transmitters, in fact I was involved in building several FM broadcast transmitters from the ground up.
At only 198kHz—which is somewhere between one 1/500th and 1/1500th its normal operating frequency—any high power VHF transmitting tetrode would be just loafing along.
No doubt the way commerce works getting a one-off specialist job to do the conversion would be expensive (I wish I could do it, I'd quote half the price and still make a handsome profit).
If the BBC is so strapped for cash perhaps it could ask the Amateur Radio fraternity to mod the TXes for free as a public service. Then after the mods the service could recommence on half power to save costs.
Also, there are good strategic reasons why this transmitting infrastructure should be kept operational on these low longwave frequencies which I haven't got time to address here.
Suffice to say, I think this proposed closure is more a hatchet job by accountants than from any long-term strategic thinking by governments.
Damn shame governments only seem to listen to nanny goat advisors these days.
I agree it's 99% ridiculous, but to play the devil's advocate: modifications could require re-certifying the transmitter due to regulations, which might make them not financially worth it after the remaining correct tubes die. Especially since regulations governing something so boutique and relatively obscure haven't probably been updated much to make stuff like this easier. (I confess high ignorance to UK law.)
My first contact with English was listening to the Radio Canada International. Then I knew that I needed to learn it to receive news that only would be in newspapers 2 or 3 days later.
Now there are none stations that I can listen at night, and I miss it
As far as I know, the UK's nuclear submarine fleet used (or still uses?) the presence of a Radio 4 broadcast signal as evidence for the continued existence of the UK. Hopefully they have other means at this point!
From 2020:
> During the time following a perceived attack, a series of progressive checks are made by submarine crews leading up to the captain opening the letter. These include trying to listen for radio transmissions from various levels of Royal Navy and Ministry of Defense command using multiple methods, and most famous of all, listening for new radio broadcasts by BBC Radio channel four, and specifically new episodes of BBC Today. […]
* https://www.twz.com/7300/letters-of-last-resort-are-post-apo...
Also:
* https://en.wikipedia.org/wiki/Letters_of_last_resort
Why are they calling this long wave instead of just AM radio?
Cause longwave (148-283 kHz) is only part of AM radio. Most of it is in medium wave (525-1705 kHz) and some shortwave (2.3-26 MHz).
LF, MF, and so on are bands, or frequency ranges. AM is a modulation technique. It, like FM and others, can be used on any band (although regulations can limit this).
Long wave != AM: long wave implies AM, but not vice versa (AM can be - and usually is - used on medium/short frequencies)
> long wave implies AM,
It doesn't: There's a lot of non-AM/non-voice stuff on longwave, most notably various digital time beacons (WWVB in the US, DCF77 in Western Europe etc.)
It's at a lower frequency, 148.5 to 283.5 kHz.