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
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