Message-ID: <5254A7912F1343C6AFD6C789BC6A0F3E@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <CAA8k23STzh0z0=AqAXBhz-AEpcT67y-5CSazZny-QT=wuDPhoQ@mail.gmail.com><2BB40A231A1A4EF8B2DB14786249FA35@AGB> <CAA8k23TRgCp7tui+P=M4ZpEZBQys8LCyM73ko5mMPDCBPiD5uA@mail.gmail.com>
In-Reply-To: <CAA8k23TRgCp7tui+P=M4ZpEZBQys8LCyM73ko5mMPDCBPiD5uA@mail.gmail.com>
Date: Tue, 17 Jan 2012 23:03:46 -0000
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Subject: Re: LF: Opera continuous changes
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Yes  that  was the thinking  , s/n is not  everything in this situation , 
rn3agc  second   OP50  did seem  to  give  negative result to  OP32  , but 
tonight , OP8  is  decoding  in the uk  quite  early . 3 db is  about  right 
for the  x2  time , but that against a  constant  noise  source, which  is 
'now  looking a little  controversial, with the  level/quantity  of 
decodes.

We did  see one  missed decode  in 4x4 , but with the  50/60  min  period 
and nothing to  show ... 32  is  back.

I'm  not  sure  on the  2:1  ratio  for the  Hf bands at the  moment , but 
beacon  collisions  are reducing  the  decode  rate  with the  longer  1:4 
time  select , but  as perhaps hf  path  losses  are not as high  , then the 
reduction  in collisions is  preferable to  allowing  a 6  dB  gain  ,  1 
watt to  4  say  as opposed  to  LF where 6 dB could be  300  to  1200  w ,

G..


--------------------------------------------------
From: "Andy Talbot" <andy.g4jnt@gmail.com>
Sent: Tuesday, January 17, 2012 10:14 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: Opera continuous changes

> yes, 50 mins is somewhat long.  But the 16s symbol period is, to a
> first approximation,  3dB more sensitive than the 8s of OP32
>
> Andy
>
>
> On 17 January 2012 21:06, Graham <g8fzk@g8fzk.fsnet.co.uk> wrote:
>> All  seismic  activity  has  aftershocks ..
>>
>> It was  felt the  Op50 /64  was  perhaps  too  long  a  capture period 
>> for
>> 136Khz
>> with  max  33% data  loss  this  was still  40mins  , which , was 
>> possibly
>> a little  too  long.
>>
>> OP32  , will  reduce to  20  mins capture  window and is  perhaps more
>> realistic?
>>
>> Any views  on this would be  appreciated
>>
>> Tnx G..
>>
>>
>>
>> --------------------------------------------------
>> From: "Andy Talbot" <andy.g4jnt@gmail.com>
>> Sent: Tuesday, January 17, 2012 9:12 AM
>> To: "o_p_e_r_a_" <O_P_E_R_A_@yahoogroups.com>;
>> <rsgb_lf_group@blacksheep.org>
>> Subject: LF: Opera continuous changes
>>
>>> Just after I'd spent yesterday morning reprogramming the PIC code,
>>> re-writing the documentation and uploading to website for general
>>> access, the coding has been changed again.
>>>
>>> That's it. I'm not changing again until something has stabilised.
>>> The version posted only yesterday will now be removed, and not
>>> replaced for the time being.
>>> If you want an independent PIC based source, you're on your own
>>>
>>> If fundamental changes are going to me made like this, please at least
>>> warn us in advance.
>>>
>>> Andy
>>> www.g4jnt.com
>>>
>>
>