DT/Herculis

[london_lassy]

Help needed please

2d Person who practices self-denial as a spiritual disciple ???e?i?

18a Acronym for frequencies below three kilohertz ?.t.?

[jan1956]

2d ascetic havn't got to 18a yet

[zeb424]

vlf

[NessieHunter]

VLF is 3 to 30kHz. Try ULF, up to 3kHz.

[JRB]

ELF - extremely low frequency is below 3 KHZ

[ulysses100]

according to dictionary.com it's ULF

[theprof]

I agree with JRB

It's ELF in the Collins English Dictionary which this compiler almost always uses. It doesn't seem to matter if the definition is technically correct or debatable.

[london_lassy]

Thank you all for your help, I think I will go with ELF

[Muzz]

Ive gone with ELF, as it is below 3 kilohertz.

Still deliberating over ABC and NBC for the North American television company.

[theprof]

The majority of earlier posts seem to suggest NBC as the correct answer. At the end of the day, it could be either. I've gone for NBC.

[Nigse]

Wilkipedia gives:-

ELF (Extremely Low Frequencies) 3-30Hz

SLF (Super Low Frequencies) 300-300Hz

ULF (Ultra Low Frequencies) 300Hz-3KHz

all the bove are below 3KHz so could be valid answers; (VLF is out as a range of 3KHz-30KHz is given) However of ULF, SLF & ELF isn't only the last (ELF) a true Acronym, the other two only being abbreviations?

[theprof]

Here's the definition from Collins English Dictionary:

extremely low frequency
noun
A radio frequency or radio-frequency band below 3 kilohertz. Abbreviation: ELF

Notice how close this definition is to the wording of the clue.

There are no entries for Super Low Frequencies, Ultra Low Frequencies or their acronyms in Collins English Dictionary.

I therefore think it's a safe bet that the answer required is ELF.