[FADCA] Transmittal speed

[bud thompson]

Bob:

The HF transfer of the 32K message was done on PacTOR 3.  The link to WB5KSD
in Dallas was good and the transmission speed reached an indicated 3200BPS
for most of the file transfer. PacTOR modes are adaptive and change rates
depending on throughput/conditions. Once the transfer started, my Airmail
screen indicated it would take less than one minute. (<1 min)

The upper rates of PacTOR 3 require a 2.4KHz bandwidth. It is a multi-tone
mode, not just two-tone M/S.

PacTOR 2 can attain up to 800BPS and PacTOR 1 maxes out at 200BPS. Both are
only two-tone M/S modes and work within a 500Hz bandwidth.

3200 is the max rate for PacTOR 3. It steps down from there to 2800, 1400,
(1200?), 800, 600, 200 - ( think that is the progression) depending on
conditions.  Most of the PacTOR 3 links on my WL2K are 1400 or greater... Of
course I don't know this unless I'm watching which isn't all the time. After
almost two months of WL2K operation now, I'd estimate that 15 percent of the
P3 transfers are at max speed, 60 percent at the next step down. This is on
any band 40,30,20, 17,and 15M where I allow P3 connects.  My regular users
are at distances from 100 miles to more than 3500 miles.  In January I had a
regular user while he took a week or more crossing the Indian Ocean in his
sailboat, but he was using PacTOR 2.

My stats show that since Jan 1 about 40-45% of the connects are PacTOR 3,
35% PacTOR 2 and the rest PacTOR 1.

I assume the rate that is shown on my screen during the transfers is the
ASCII transfer rate, so the effective throughput would be faster yet
depending on how much compression is being used. At a 40% compression, a
3200 rate would be 1.4x that much effective or nominally 5KB.  I also assume
the posted rate is the actual transmission rate which would have to be
reduced when the effective rate is determined as these are QRQ modes, not
full duplex.

Of course the 80 seconds on my transfer to Dallas  included all the
systematic overhead as well.

Rick KN6KB can weigh in here to straighten out any kinks I just made.

bud

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----- Original Message -----
From: "Stacey & Bob H." <stacey.bob@gte.net>
To: <fadca@mailman.qth.net>
Sent: Sunday, February 16, 2003 09:49
Subject: [FADCA] Transmittal speed


> Bud Wrote:
>
> Yesterday I sent a ham-to-e-mail message with two attachments. One was an
MS
> Word file (a 30K binary file), the other a small DOS.txt file. The actual
> text in the e-mail message was only a reference to the testing. The total
> e-mail message was just over 32Kbytes. From my home Airmail set up in
> Deltona on 20M I linked with WB5KSD, a frequency/band scanning WL2K
station
> near Dallas, TX. I got lucky and made the link in about 15 seconds - it
> would have taken 45 seconds had I missed his scanning the frequency the
> first time. Once linked the entire 32K message was sent and we were
> disconnected in about 80 seconds. I then walked across the shack about 10
> ft to my XYL's computer and the e-mail message was in her in folder.
>
> Bob: Bud at what baud rate did you pass a 32k file in 80sec? At 1200 baud
it
> would approximately 9 minutes.
>
> Bob N4WFH
>
>
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