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VE2HAR > MT63 15.03.05 20:46l 219 Lines 5967 Bytes #-7297 (0) @ WW
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Subj: Re: [MT63]
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Point 1. Checking the byte size will not tell you anything other than if=20
a byte is added or missed. Checksum is the correct way to do that. It=20
adds all of the data together to creat a binary number. Filecheck also=20
works by doing a direct comparison byte by byte of the data and giving=20
an indication of where the error or discrepancy is.
Point 2. 3,000 words is not less than 3,000 bytes. That would be closer=20
to (8 bits/byte X 5 Bytes/word + spaces and puncuation) 144,000 which at=20
200WPM would take 12 minutes to send.
The file needs to be a bit smaller. I recommend a small gif or bmp file=20
of a test pattern. 1) so that it is able to be sent within 3 - 4=20
minutes, not over 10 minutes for ID purposes. 2) A quick visual=20
inspection of the file would show gross errors.
Steve/WM5Z
karl larsen wrote:
> Hi Walt, I agree we need to define our text that we send, the amount=20
>of bytes that are sent and then have a method to check the number of=20
>errors. The size can be more than 3 Kbytes but no larger is better. The=20
>text can be anything but it must conform with the ASCII text format. The=
=20
>test text must be sent to this list so everyone that is interested can=20
>get the accurate file. In linux you can check both files by knowing=20
>there total byte size. If they are the same, it's perfect. You get the=20
>byte size with ls -al.
>
>Using the Linux gMFSK I can send the test file directly with clicking=20
>File and then Send file. When I receive the test file I can simply cut=20
>it out of my lof file. I have my system set to log everything. Fun to=20
>look at later.
>
>I have a file we can use. It is the ARRL bandplan. It is way too long=20
>but I will cut it down to about 3,000 words.
>
>karl
>
>
>dubose@texas.net wrote:
>
> =20
>
>>Thanks to Patrick, F6IN, for bringing PathSim to our attention. This i=
s truly a
>>nice application.
>>
>>Building on what I believe Tomi or others have said, as well as my own =
thoughts
>>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 o=
ut, my
>>several E-Mails with Charles, G4GUO.
>>
>>Back in Jan/Feb of 1990, the US TRANSCON began "testing", on-the-air, H=
F
>>transmissions of a file which became their standard. It was a 40KB fi=
le. The
>>modes being used were the MIL-STD-188-110 type. These were interesting=
test.=20
>>The MD5 sum was used on each received file to verify that its was the s=
ame as
>>the original file. Throughput and accuracy were important.
>>
>>G4HPE in his paper "A PRACTICAL EVALUATION AND COMPARISON OF SOME MODER=
N DATA
>>MODES" (http://www.rsgb.org/emergency/articles/datmodes2.pdf) Richard s=
peak of
>>the test he did on MT63 and MFSK16.
>>
>>Also, on page 17 of Rick=92s, KN6KB, presentation to the DCC last Septe=
mber
>>(2004), he shows throughput using an HF channel simulator from KC7WW=92=
s Oregon
>>Software Factory.
>>
>>G4HPE=92s test concluded that MT63 had a throughput of 200 WPM at a =96=
5 dB SNR on a
>>poor CCIR Channel. KN6KB=94s results for Pactor II/III indicate a simi=
lar (if not
>>lower) throughput under the same signal conditions.
>>
>>While I do not doubt these findings, I believe that as some in this gro=
up are
>>very technical, we need to develop a standard method of testing various=
new
>>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 o=
ne space
>>per word, 6 bytes =852.4KBPs).
>>
>>2) Generate this file in the mode to be tested and store it electronica=
lly on a
>>computer hard drive, CD or other magnetic storage media.
>>
>>3) =93Play=94 this file through the AE4JY=92s PathSim application at th=
e 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=
the output.
>>
>>
>>5) With software techniques to manually determine the throughput at eac=
h 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 thi=
nk its is
>>within the capability of a number of list members and the results might=
be VERT
>>INTERESTING.
>>
>>You comments solicited.
>>
>>Thanks & 73,
>>
>>Walt/K5YFW
>>
>>
>>
>>
>>
>><< Try MT63 on 80m - great fun!>>
>>
>>- The MT63 Reflector -
>> MT63@egroups.com
>>
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>>MT63-unsubscribe@onelist.com)
>>
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>>
>>
>>
>>
>>=20
>>
>> =20
>>
>
>
>
><< Try MT63 on 80m - great fun!>>
>
>- The MT63 Reflector -
> MT63@egroups.com
>
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