Thanks Jim - I have to keep tabs myself at work whats actually happening in this domain and theatre (in more ways than one) - I guess Ill see the next release of a Chinese text Navtex receiver probably in a couple of weeks down the local market. The interesting thing is the guys down the road are actually testing on 484 not 486 and we have this lovely asssigned versus carrier debacle that crops up now and again - some say 2 some 2.1 Khz off set etc etc. I didnt go into that with the station manager there but its going to be interesting - I still recall of lot of my miltary radio days with the PRC series used to keep my head scratching a lot on what I was really transmitting on...still do.
I picked up the China bit from
http://www.iho.shom.fr/COMMITTEES/CPRNW/CPRNW9/CPRNW9-3-3-1.pdf
and they cite here and else where the issues of limiting power cos of co channel.
My local Navtex station is some 100 miles from here and luckily theyve got the tuning right - it can be a bit of a mess, and I recall some of the awful tuned Navtex transmissions that plagued me in Singapore marine trying to listen on 500 -
I do miss awfully the musical and not so musical A2 sounds when I was at sea....Argh Jim lad - isnt it talk like a pirate day too?
The noise is kicking up a bit even on 500 but will be looking your way this evening on WSPR and the speaker open for Mal.
Laurence
KL1 X in BY3A
OM89UA China.
> From: [email protected]
> To: [email protected]
> Date: Sat, 19 Sep 2009 11:09:06 +0100
> Subject: LF: Re: 500 still in use?
>
> Dear Laurence, LF Group,
>
> The 468kHz frequency does seem to be slated for Chinese Navtex broadcasts -
> apparently 424kHz is being used for Japanese language Navtex too. This seems
> to coincide with a general shift to using 490kHz for Navtex weather
> forecasts instead of "local language" as it was originally supposed to be.
>
> I beleive the international agreements relating to Navtex say that "no more
> than 1kW" should be used for Navtex broadcasts, and then only under
> exceptional circumstances, in order to minimise mutual QRM. but if you look
> at manufacturer's TX offerings, you will struggle to find one less than 1kW.
> Fun for DXers, I suppose, but not so clever when you actually need the info!
>
> Several years ago when a 500kHz allocation was first mooted, I spent some
> time listening to 500kHz, and most nights used to hear Italian coast
> stations - IAR was one I think. They would appear on 500k and tell you to
> QSY to some nearby frequency. When you did so they would broadcast a long
> list of ships' callsigns, I presume who they had traffic for. But I never
> did hear any 2-way operating, and got the impression the whole thing was
> computer generated. I haven't heard these coast stations since about 2003,
> or maybe before.
>
> Cheers, Jim Moritz
> 73 de M0BMU
>
> ----- Original Message -----
> From: "Laurence BY3A-KL1X China" <[email protected]>
> To: <[email protected]>
> Sent: Saturday, September 19, 2009 9:40 AM
> Subject: LF: 500 still in use?
>
>
>
>
>
> Im asked whether 500kcs or kHz etc is still in use here and yes it is -
> heres a TTT TTT Nav warning on 500.00 Khz at Hr +18 from XSV Tianjin radio
> about 15 miles from me just a few mins ago.
>
>
>
> I dont hear Ship to Ship or Ship to Shore on MF, or should I say I havent
> yet and none of my ships or platforms are equipped here, but the Chinese
> announced back in 2007 that 486 Khz (assigned) is to be used for a "National
> language channel" - Im not sure if this relates to safety traffic/navtex or
> gen bsct - or whatever, but Tianjin is just increasing its output power on
> that freq to 5Kw, and dont I know it.
>
>
>
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