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" <[email protected]>
Sent: Friday, April 20, 2012 6:20 PM
To: <[email protected]>
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" <[email protected]>
To: <[email protected]>
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
|
