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VE2HAR > MT63 15.03.05 17:37l 127 Lines 3586 Bytes #-7297 (0) @ WW
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Thanks to Patrick, F6IN, for bringing PathSim to our attention. This is =
truly a
nice application.
Building on what I believe Tomi or others have said, as well as my own th=
oughts
about having a "test" file. Also, looking at G4HPE's papers found at
http://www.rsgb.org/emergency/datamodesinfo.htm . And not to be left out=
, my
several E-Mails with Charles, G4GUO.
Back in Jan/Feb of 1990, the US TRANSCON began "testing", on-the-air, HF
transmissions of a file which became their standard. It was a 40KB file=
. The
modes being used were the MIL-STD-188-110 type. These were interesting t=
est.=20
The MD5 sum was used on each received file to verify that its was the sam=
e as
the original file. Throughput and accuracy were important.
G4HPE in his paper "A PRACTICAL EVALUATION AND COMPARISON OF SOME MODERN =
DATA
MODES" (http://www.rsgb.org/emergency/articles/datmodes2.pdf) Richard spe=
ak of
the test he did on MT63 and MFSK16.
Also, on page 17 of Rick=92s, KN6KB, presentation to the DCC last Septemb=
er
(2004), he shows throughput using an HF channel simulator from KC7WW=92s =
Oregon
Software Factory.
G4HPE=92s test concluded that MT63 had a throughput of 200 WPM at a =965 =
dB SNR on a
poor CCIR Channel. KN6KB=94s results for Pactor II/III indicate a simila=
r (if not
lower) throughput under the same signal conditions.
While I do not doubt these findings, I believe that as some in this group=
are
very technical, we need to develop a standard method of testing various n=
ew
modes under varying conditions using Moe Wheatley=92s, AE4JY, PathSim.
Here is my suggestion.
1) Create/develop a standard file of at least 400 words (5 characters one=
space
per word, 6 bytes =852.4KBPs).
2) Generate this file in the mode to be tested and store it electronicall=
y on a
computer hard drive, CD or other magnetic storage media.
3) =93Play=94 this file through the AE4JY=92s PathSim application at the =
following HF
Simulation parameters:
CCIR 520-2 Conditions SRN (in dB)
Good Conditions +10 +5 0 -5
Moderate Conditions +10 +5 0 -5
Poor Conditions +10 +5 0 -5
Flutter fading +10 +5 0 -5
Low-latitude quite +10 +5 0 -5
Low-latitude disturbed +10 +5 0 -5
Mid-latitude quite +10 +5 0 -5
Mid-latitude disturbed +10 +5 0 -5
High-latitude quite +10 +5 0 -5
High-latitude disturbed +10 +5 0 -5
4) Record output or =93play=94 it through the mode detector and capture t=
he output.
5) With software techniques to manually determine the throughput at each =
signal
condition.
6) Document the results and provide the results to interested parties.
I realize that this is just a rough draft of a testing process but think=
its is
within the capability of a number of list members and the results might b=
e VERT
INTERESTING.
You comments solicited.
Thanks & 73,
Walt/K5YFW
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