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" <[email protected]>
Sent: Friday, April 14, 2017 12:29 PM
To: <[email protected]>
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
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
|
