Message-ID: <24B011E2D7E840978C5188935F8138C7@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <4FC1126C.11635.CFA0D5@mike.dennison.ntlworld.com> <006c01cd3b8e$00d27600$4001a8c0@lark>
In-Reply-To: <006c01cd3b8e$00d27600$4001a8c0@lark>
Date: Mon, 28 May 2012 20:53:06 +0100
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Subject: Re: LF: Re: Opera QRM picture
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After some  investigations  by  those  using the  Op  system, General 
consensus is ,

The  posted  image is not a  Op transmission, for OP8  there should  be a  8 
second  cyclic modulation  with  approx  50 %  MK-SP  ratio.  or in the 
case of  OP32  32  seconds ,  the transmission  should last  8 or 32 
minutes.

The indicted stability would  prevent  a decode

The carrier placement routine seeks to  place the  carrier  at the  lowest 
s/n  point in the defined pass  band , to prevent  overlaying of 
transmissions

If under direct VFO control, the  operator is  responsible for the 
placement , noting that  when operating  at the  lower  levels , it  may not 
be possible to  see or  hear   the  signal's , this would  not appear to be 
the  case in this  instance.

As for  spectrum efficiency, up to  4 and possibly more  transmissions could 
be  fitted in the  space occupied by the  various  frequency dependant 
modes, so its most unlikely  that conflicts will  occur.

G..



--------------------------------------------------
From: "Alan Melia" <alan.melia@btinternet.com>
Sent: Saturday, May 26, 2012 10:18 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: LF: Re: Opera QRM picture

> Hi Mike yes but it doesnt mean that digital mode ops dont need to listen 
> on
> the frequency.....that old law of amateur radio :-))
>
> Alan
> G3NYK
> ----- Original Message ----- 
> From: "Mike Dennison" <mike.dennison@ntlworld.com>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Saturday, May 26, 2012 5:27 PM
> Subject: LF: Opera QRM picture
>
>
>> Here is a picture of an Opera signal on 137.695kHz accidentally
>> QRMing my QSO with a very weak DR650BAR - his DFCW10 can be seen
>> sending the 'V'of 'XDV' and the 'B' of 'BAR' in DFCW before the QRM
>> starts.
>>
>> Now, that's why we do bandplanning.
>>
>> Mike, G3XDV
>> ==========
>>
>
>
> ----------------------------------------------------------------------------
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>>    ---- File information -----------
>>      File:  Opera_QRM.jpg
>>      Date:  26 May 2012, 17:17
>>      Size:  50379 bytes.
>>      Type:  JPEG-image
>>
>
>