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Date: Wed, 23 May 2007 23:14:43 +0100
To: rsgb_lf_group@blacksheep.org
Cc: colin@g3psm.net
From: Alan Ibbetson <alan@g3xaq.demon.co.uk>
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Subject: Re: LF: RE: 500kHz Distance
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Status: O

John,

I think your group has done a fantastic job getting UK amateurs the 
first general operating permits for 500K in Europe.

I'm interested in aerial experiments but, to make this offer some 
returns on the effort, I would favour a power limit at the aerial input, 
as we have on the higher bands. That way I will be motivated to make my 
electrically small aerial as efficient as possible within its domestic 
setting.

I don't really mind what that power limit is. Although 20W or more might 
be nice for DXing, it doesn't seem necessary for inter-UK contacts. I 
would be happy with 4 or 5W, which is what most people seem to be 
running. Once other countries gain access to the band I think there will 
be stronger case for higher power.

I'm a newcomer to the band, so treat these comments as "from a novice".

73,

Alan G3XAQ

In message <Zen-1HqyLJ-0000Zb-HL@heisenberg.zen.co.uk>, John W Gould 
<jwgould@iee.org.uk> writes
>Thought that I had better respond to Laurie's e-mail, now a few days ago.
>
>This is because the matter of the power level is to an extent under 
>review by Ofcom.  If you recall we, RSGB, asked back in 2004 for a 1W 
>ERP limit as that was consistent with experience at 136kHz.  A ERP 
>limit also gives Ofcom a real view as to what the likely coverage would 
>be at any particular bandwidth.  That we were offered -10dBW ERP 
>reflects both a bold step by Ofcom and also some caution, given that 
>they have to an extent taken an interesting view of ITU Radio 
>Regulation 5.58 to our benefit.  RR 5.58 defines 500kHz as an 
>international distress and calling frequency for Morse radiotelegraphy. 
>Ofcom may have taken the decision as they may expect to be withdrawn at 
>WRC07, and on knowledge that in this part of the world 500kHz is no 
>longer used as an international distress calling frequency.  Other 
>authorities have not been so minded, as Dick, PA0SE, recently 
>discovered; they prefer to wait until such time as RR 5.58 has been deleted.
>
>Whilst we are currently limited to -10dBW RSGB/Ofcom are keeping the 
>matter under review and it may be timely, now that we have a good body 
>of experience to request that the limit be reconsidered.  As far as I 
>am aware no interference complaints, or even local RFI problems have 
>been received, and our operating and conformance to licencing 
>conditions have been exemplary.  From comments on this group it may be 
>better to request say a 10 or 20W power limit at the aerial feed-point, 
>for reasons mentioned by Laurie.  Whatever change to the limit is 
>agreed, if indeed any in the near term, it will have to be a cautious 
>change until such time as the Radio Regulations are more helpful in 
>allowing administrations to consider proper secondary allocation to the 
>Amateur service.  This may or may not happen for a while, as we are 
>only really working at present to get the matter firmly on the WRC2011 
>agenda, such is the speed of the ITU.  There is good practical reason 
>for making a request of this nature as one of the reasons why the ITU 
>process seems so slow is that for normal protocol to be followed one 
>needs to have had technical studies completed that relate to the new 
>proposals for the part of the spectrum in question.  Our activity 
>between 502 and 504kHz, along with that by the US, Germany and Sweden 
>may qualify as such a study, so continuing the experiments at a higher 
>power, with the added challenge of maximising ERP from a fixed 
>feed-point power limit would add some breadth to our work.
>
>Of course, the unexpected could always happen, and we get something 
>sooner in the margins of Agenda Item 1.14 at this year's WRC.  However, 
>as Agenda Item 1.14 is to review the operational procedures and 
>requirements for GMDSS and other related provisions our chances are 
>slim, as the Maritime service is likely to want to reuse the frequency 
>around 500kHz.  However, it is an agenda item concerning this part of 
>the spectrum so the possibility, however distant, must be there.
>
>I'd be interested in any further views to Laurie's proposal; I'am open 
>to suggestions as to the power level, but it will be important to hit a 
>target that is both challenging to the experimenter, helpful for 
>continued propagation research and also one that will not provide too 
>much risk for Ofcom in terms of coordination with the primary user service.
>
>73 John, G3WKL
>RSGB HF Manager
>IARU Region 1 LF Coordinator
>
>
>
>
>
>

-- 

Cheers,

Alan G3XAQ
alan@g3xaq.demon.co.uk