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Re: LF: Re: VLF Earth Mode does NOT need an NoV - official at last

To: [email protected]
Subject: Re: LF: Re: VLF Earth Mode does NOT need an NoV - official at last
From: Roger Lapthorn <[email protected]>
Date: Wed, 19 Jan 2011 15:24:33 +0000
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Hi Mal,

I am unaware of the situation with cave radio and licences.

With regard to UK VLF experimenters I don't think it is true that everyone necessarily wants to radiate a far-field signal as far as possible. Certainly all the current NoV holders would like that, although with my small antennas I don't hold out much hope here. There is another set of experimenters who have for 40-50 years or longer played with earth mode "through the ground" communications.

The 18.1.11 OFCOM email does appear to give a tacit go-ahead for anyone to experiment with essentially non-radiating earth mode conduction without real restriction on a non-interference basis. To my knowledge, this is the very first time anyone at a UK government telecoms authority (Post Office, MPT and now OFCOM) has ever made this statement.

It may be semantics, but I believe this is an important statement.

73s
Roger G3XBM

On 18 January 2011 18:34, mal hamilton <[email protected]> wrote:
Two issues here
No NOV required for Earth Mode (conduction/induction) applicable to Cave divers where it is not intended to propagate a signal into the ether, but to communicate through the earth.
however
Since it seems to be the intention by the majority posting on this reflector interested in frequencies around 9 Kcs and below to propagate/emit a radio signal to be intercepted some kilometres or hundreds of kilokemetres then a NOV or Licence seems necessary.
so
what is the object of this clarification, it seems irrelevant to the intentions of most engaged in VLF experiments as far as I can make out.
ie everyone is trying to emit a RF signal  with the best Far Field coverage hoping to cover the best possible range, hundreds of Kilometres.
Is someone trying to hoodwink OFCOM.
g3kev
 
 
----- Original Message -----
Sent: Tuesday, January 18, 2011 3:11 PM
Subject: LF: VLF Earth Mode does NOT need an NoV - official at last

Today I received this letter from OFCOM, which clarifies the legality of operating so called "earth mode" (conduction/induction via the ground) experiments at frequencies below 9kHz in the UK. Note the sentence in Paul's letter saying, "We would not normally issue NoVs for communications using non-wireless telegraphy apparatus/stations i.e.  where you rely only on conducted emissions and where there are no intentional radiated emissions.".

Wanting to check earth mode propagation behaviour at a series of frequencies below 9kHz to see how results compared (earlier tests at 0.838kHz seemed around 10dB better than at 8.76kHz), I asked OFCOM if I needed an NoV extension to be legal. One could also argue that such tests at frequencies above 9kHz would also be legal as long as it does not cause any "Undue Interference to any wireless telegraphy" and one was not intending to radiate.

This sounds a wholly pragmatic answer from a government body.

Roger,

 

Rod Wilkinson has now left Ofcom , so I’m responding to your query.

 

You should seek you own legal advice as Ofcom is unable to give legal advice, however, we would issue NoVs, where appropriate, for wireless telegraphy apparatus/stations.

 

In the case of the 9 kHz band NoV we currently stipulate the frequency band only around 9 kHz as discussed with the Met Office and we do not intend to issue NoVs for lower frequencies in the band. We would not normally issue NoVs for communications using non-wireless telegraphy apparatus/stations i.e.  where you rely only on conducted emissions and where there are no intentional radiated emissions.

 

I would also draw your attention to other relevant legislation (e.g. Wireless Telegraphy Act 2006) and the Terms of the Amateur Licence and in particular to clause 7(3); “Notwithstanding any other terms of this Licence, the Licensee shall ensure that the Radio Equipment is designed, constructed, maintained and used so that its use does not cause any Undue Interference to any wireless telegraphy”.

 

I am also copying in Ash Gohil in the Ofcom Licensing Centre who is in the team that Rod worked in. Please address any further queries to him in the first instance.

 

I hope this helps.

 

Kind regards,

 

Paul

 

:: Paul Fonseka
Spectrum Policy Group-Business Radio
+44 (0) 20 7981 3116
[email protected]


Hope this is of interest.

73s
Roger G3XBM
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