Message-ID: <8CE7B218E1414CCF948FDAAF7F315812@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
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Date: Fri, 20 Apr 2012 19:46:44 +0100
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Subject: Re: LF: Re: 136 propagation a QRO  secret  ?
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R Alan,

Yes  a lot of myths linked to the 'Bright light's' of 136 , but I think the 
UK/VK   full  decode is  yet to be achieved ?  ive seen   wiggles  and 
squiggles down under ,  bit  like  starting a old  vintage  engine, spark 
plugs in the  oven, that  sort of  thing , but  not firing  on all 
cylinders yet ?

I did know  about the  previous tests , must of taken  some  setting  up as 
well , we  could  do  with a  little of that old time  pioneering  spirit 
now, but  I assume  the  same  arguments  must of  accompanied  the  change 
from cw to slow ?

The  Op beacon and  QSO mode  ( 15  chrs  120 second  tx  -20 dB s/n)  ,is 
certainly  taking a  can opener to the  established norm's   round  s/n 
measurement  and propagation observations at  VHF and  MF/LF , for  example 
the day light  path  decodes from  PA/RA  on 136 , I for  one always 
assumed , you  needed near total  darkness , not  3 or 4  hours  of 
daylight in the  path ! sure wspr would  do the  same thing , but  thats 
not a  MKC  mode  (Morse key  compatible), using   the 'Peoples Beacon' 
anyone  can  join in and get a  set of  results  with any set up and  with 
the  longer tx times , the  s/n is considerably  lower , OP2 is about the 
same as  wspr , with  -3 db for every   X2 in time ,  OP8 is  -6 dB lower, 
and that's a  lot of  PA amps saved !  (power amps)

USA stations  are  running  on 145 MHz over a  250 mile  path, using the 
OP0.5    (30 seconds)  mode with  good  results as well. (showing as  70 MHz 
on the psk map, to prevent confusion , until a  frequency can be defined)

s/n  'mode'  comparative  measurements   also  are  not  always  indicating 
the  observed performance either , may  be  linked to the  pulsed nature of 
the  transmission , everything  is  referenced  to  'average'  in the  Op 
system, the  s/n reading is  calibrated to the  sim-path  propagation 
software  and  takes the  average of  ' all ' the  received  data  pulses , 
so  if you  loose  50% then the  s/n is  reported -3dB lower , its 
reporting  the  path  usability  rather than the  max/min  signals (ROS Hf + 
MF)  gives a  s/n  and margin , which is  the fade difference, between the 
lower  and  higher levels , ie  two values  are  presented.

4 months  in and  it looks  quite  stable , number of  false  decodes  are 
quite  low , usually  linked to  500 Khz  operation , which sort of 
confirms , its a  noisy place  for  some reason! at least its given a good 
justification  for the  experimental 500 licence  as  development  for 
ROS-MF and  Opera  where  both initiated  by the  500 band allocation  and 
operations  !

73 -G..



--------------------------------------------------
From: "Alan Melia" <alan.melia@btinternet.com>
Sent: Friday, April 20, 2012 6:20 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: LF: Re: 136 propagation a QRO  secret  ?

> Hi Graham you may not be aware that the only modes that were available in
> the early days when the 1st TAs were achieved was QRSS3. Robert Horne,
> author of Spectrogram saw now use or reason for a slower
> waterfall.....remember he is a biologist and this suite was written for
> recording and analysing animal and marine mammal sounds. The results were
> obtained in a period or high geomagnetic activity just after the peak of 
> the
> last Solar max (Geomag activity trails sun-spots by about a year) We have
> just had the quietest minimum for years and the level of activity is
> relative to the last max still quite low.
>
> The modern digital modes are around 20dB more sensitive than QRSS3  this
> accounts for the difference between 100s watts and less that 10 watts, 
> even
> allowing for quieter conditions. I think this is what you usually call
> "progress"  :-))
>
> Alan
> G3NYK
>
>
> ----- Original Message ----- 
> From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
> To: <rsgb_lf_group@blacksheep.org>
> Sent: Friday, April 20, 2012 11:32 AM
> Subject: LF: 136 propagation a QRO secret ?
>
>
> Have the high power operators on 136  been  keeping  the  real  potential
> of  136 propagation   a  secret  ?  writing you  name in neon light is one
> thing , but  behind the  glow  of the sign , previously  un seen, the data
> recording  Op beacon system is  starting to  reveal  some  interesting
> features of this  band.
>
> Results  from the  first  'plug and play'  'peoples'  beacon,  seem  to
> show , DX operation  on 136  is  not quite as  difficult  as was  perhaps
> made out , from the  first  TA  decode  of  OP8  , using a
> Parasol-on-a-Stick  , with a few  hundred watts  , to  RA3AGC long wire 
> to
> the  trees , with  similar  power and PA0A 'small array' .. 2000 Kmtr  +
> decodes  are showing up on a  quite  regular basis , may be more  than 
> that
> offered  by  500 KHz ?
>
> VK  136 operators  have expressed  interest in  setting  up  sked's  to
> make, what  could be the  first full  call  sign  decode  , to down under,
> but to  date, it  seems  there  are no   transmit  takers this  side ,
>
> Technically, the  processing  gain of OP32  , is  very  close to the
> estimated   -40 dB  path  loss  , EU-VK and  should  require  16  mins  of
> carrier  above the  s/n threshold in 32 mins   to  decode  ...
>
> Anyone  tempted to make  a sked  ?
>
> G,,
>
> 24 hour  usage from   http://pskreporter.info/pskmapn.html
>
>      Txmtr Rcvr Band Mode Distance Time (UTC)
>      7L1RLL 7L1RLL 2200m OPERA 0 kms 09:54:58
>      PA3BHT PA3BHT 2200m OPERA 0 kms 09:53:41
>      PA0WMR PA0WMR 2200m OPERA 0 kms 09:45:35
>      JH1ARY JH1ARY 2200m OPERA 0 kms 09:43:42
>      UA0SNV-1 UA0SNV-1 2200m OPERA 0 kms 09:36:19
>      JP1ODJ JP1ODJ 2200m OPERA 0 kms 09:34:55
>      JF1PSS JF1PSS 2200m OPERA 0 kms 07:38:29
>      UA0SNV UA0SNV 2200m OPERA 0 kms 07:33:19
>