Message-ID: <B59EEC22DC694CC283155855E91ED90E@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <33CE58375F0E485AA41770E0C8552335@AGB> <21C25792F3E84B2CA4CA3AEBCB7D4011@AGB> <71a26ccf-2a24-26d0-9a7e-aa1485ab1630@n1bug.com> <6E4F585DCCD348E9B106EF92AB646B4A@AGB> <4b309ff5-66c9-10e4-48d9-b158fb68bf06@n1bug.com>
In-Reply-To: <4b309ff5-66c9-10e4-48d9-b158fb68bf06@n1bug.com>
Date: Fri, 14 Apr 2017 15:04:22 +0100
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Subject: Re: LF: 136 OP32 LAST 24HR
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Status: O

Good  set of  results from last night Paul, !

Quite  interesting , that  the  system is  decoding at the  lower end 
f  -30 dB  most of the  time.

136  was a band , spent some time  going over previous qrss  plots ect to 
try and  draw a line through ,  signal  levels ,  qsb  , as to  what signal 
levels and  fade  could be  reasonably expected   over the the TA   path , 
guess the  parameters  set  are not too  far off ...

The  path  window will  shorten , but  should  still  see spots from UK / 
EU, or your side , may be  from VE7 ?

73-Graham
G0NBD

--------------------------------------------------
From: "N1BUG" <paul@n1bug.com>
Sent: Friday, April 14, 2017 12:29 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: 136 OP32 LAST 24HR

> Thanks for the additional explanations Graham. That helps clarify things 
> for me.
>
> I had five full decodes of 2E0ILY last night with no more than 5% fade on 
> the worse of them. Looks like Opera is going to keep the trans-Atlantic 
> season going for a while.
>
> 73 Paul
>
>
> On 04/13/2017 12:14 PM, Graham wrote:
>> Thanks  Paul,
>>
>> Yes , that's  a  full  decode ,  -40 is round the  switch over point ,
>> The  % fade is  the  amount of lost  'bits'  along  the  time  line , 
>> the
>> graphic , simply  shows , 'where'  the  bits  where 'lost'
>> A decode or Dynamic  spot  may be achieved with a  loss  up to approx 
>> 60%
>> of the  data ,  either randomly , or  in block's   along the  time line .
>> The  displayed  s/n  is the  average over the  Tx period , as  is  the
>> Frequency [ recovered  audio] average  of the  Tx
>>
>> Using Manchester coding ,  There  are  no  synch requirements ,  each 
>> bit
>> contains ''data  and  sync''  , so  its  impossible  for the  system to
>> loose  lock,  ie,  any bit that  is  recovered is  usable , so  interim's 
>> of
>> static  / noise ,  the  duration of the  Tx pulse  compared to the  noise
>> bursts is  'very long' , this coupled with tailored dsp  routines , 
>> provides
>> good  performance on the  lower bands ,  as  dose  the 'dispersed' 
>> decoder
>> version , deployed at VHF , which provides  immunity  to Doppler  , Luis
>> EA5DOM ,  used the  Op1  [ 60 second ]  to achieve  EME on 23 cm , with
>> round 50% data loss ,
>>
>> 73-Graham
>> G0NBD
>
>
> -- 
> Paul
> N1BUG  160m-2m         DXCC Honor Roll
> WI2XTC 2200m-630m Experimental license
> FN55mf      ME      Piscataquis County
> http://www.n1bug.com
> http://www.aurorasentry.com
> 

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