Re: LF: opera 137 beacon going

["Graham" <g8fzk@g8fzk.fsnet.co.uk>]

Ok Andy

No problem , may  be some  one will  take a look  for  you ?
you  may need  to  drop  to  Op31 , but what  ever the  decode
you  can  work  back  over the min  power req

GL -G.

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From: "Andy Talbot" <andy.g4jnt@gmail.com>
Sent: Tuesday, January 10, 2012 10:01 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: opera 137 beacon going

> No, the only Tx I have for LF these days is the 700 Watt job.   Its
> switch mode .
> Changing taps may bring it down to 300 watts, but no less.
>
> I'll have a look though the junk-junk box (stuff destined for rallies
> / dismantling  etc)  -  may still have a QRP Tx from years gone by,
> probably a 73kHz one that should go at 137
>
> But it would be nice to be copied in the US using the QRO.   Something
> I'd never thought likely with this antenna ever before.
>
> Andy
> www.g4jnt.com
>
>
> On 10 January 2012 21:21, Graham <g8fzk@g8fzk.fsnet.co.uk> wrote:
> > Opps
> >
> > Spent  so  long  on op2  , just realises  your  OP8
> > OP8 -32dB Op31 -38 dB S/N Mean (not peak) 21:07 136 G8IMR de G4WGT Op8 
> > 314
> > km -18 dB in Coppull, nr Preston
> >
> > That is  +20 dB over the  s/n  limit .. you  should  be ok  down to 600 
> >  >>
> > 60 >>  .... 6 watts
> > Can  you reduce  to  that  level ?
> >
> > G..300
> >
> >
> >
> >
> > --------------------------------------------------
> > From: "Andy Talbot" <andy.g4jnt@gmail.com>
> > Sent: Tuesday, January 10, 2012 8:04 PM
> > To: <rsgb_lf_group@blacksheep.org>
> > Subject: Re: LF: opera 137 beacon going
> >
> >
> > > 600 Watt of Rf to 7m high Tee with Gnd loss about 80 ohms.   I reckon
> > > about -40dBi gain so call it a few tens of mW
> > >
> > > Andy
> > >
> > > On 10 January 2012 19:58, Graham <g8fzk@g8fzk.fsnet.co.uk> wrote:
> > > > Reaching  Gary  with   +7 dB  in hand , what  is the  carrier  power ?
> > > >
> > > > Be  very interesting  to see  what  the s/n  would  be  from MAL
> > > > over similar  range  and  similar  path , with  all  that  wire out
> > > > should  be able to  catch  Andy's  beacon into the  +dB scale
> > > >
> > > > G..
> > > > 18:49 136 G8IMR de G4WGT Op8 314 km -19 dB in Coppull, nr Preston
> > > >
> > > > --------------------------------------------------
> > > > From: "Andy Talbot" <andy.g4jnt@gmail.com>
> > > > Sent: Tuesday, January 10, 2012 4:06 PM
> > > > To: <rsgb_lf_group@blacksheep.org>
> > > > Subject: LF: opera 137 beacon going
> > > >
> > > > > Having had to modify a 137kHz source to be able to generate on-off
> > > > > keying, I'm transmitting a signal using 2.048s symbol mode on 137420Hz
> > > > > 33% duty cycle (for now)
> > > > >
> > > > > This is based around my PIC generator for the mode
> > > > > Details at   http://www.g4jnt.com/PIC_Opera_Source.pdf  and
> > > > > http://www.g4jnt.com/OperaBeacon.zip
> > > > >
> > > > > As its an independent source, with no PC in the Tx chain - no IP
> > > > > packets will be sent to t'web showing the details
> > > > >
> > > > > and its definitely gettign out....
> > > > >
> > > > > 15:46 136 G8IMR de F6CNI Op8 391 km -28 dB in 136 kHz dial nr Paris
> > > > >
> > > > >
> > > > > Andy
> > > > > G4JNT