ARLA/CLUSTER: Como receber os boletins da Second Generation Amateur Radio Network

[João Costa > CT1FBF]

Receiving SGARN Multicasts


The Second Generation Amateur Radio Network (SGARN) transmits
bulletins of interest to amateur radio operators, daily.

These bulletin transmissions are sent via AMP, Amateur Multicast
Protocol, which allows an unlimited number of Client (receiving)
stations to receive bulletins from a single multicast server at the
same time, with 100% accurate copy.

This is very similar to what the ARRL's W1AW station does, the
difference being that SGARN's AMP transmissions allow for errors in
reception to be corrected for verified 100% accurate copy.

Software:

SGARN has adopted W1HKJ's programs FLDIGI and FLAMP as the best
possible software for our use on HF.

To receive the SGARN multicasts, you will need the current version of
FLDIGI and FLAMP from the W1HKJ website.

w1hkj.com

At the top of the page there is a DOWNLOAD link. Go there and download
FLDIGI and FLAMP for your operating system. There are versions
available for Windows, Linux and OSx.

Software Setup:

To operate a Client (receiving) station, you must run FLDIGI, then
FLAMP so that they run together. Consequently, the SGARN-specific
setup for FLDIGI will be described first, then the setup for FLAMP,
then a few notes about running them together to receive the SGARN
multicasts.

FLDIGI:

You may already be using FLDIGI, as it is the most popular digital
multimode program for amateurs at this writing. Many new users of
FLDIGI can get started by placing their computer's microphone close to
the radio speaker in order to decode the digital transmissions, but
best performance is obtained by using a ham radio soundcard interface
which connects your computer and radio together so that they may hear
each other directly.

Any of the popular soundcard interfaces will do... Pick your favorite,
what somebody you trust uses, what is cheapest, or what works best
with your equipment. Mine is a home-brew haywired Frankenstein's
monster, but it works and that's the main thing.

When you first start a new installation of FLDIGI, there is a setup
routine that all must go through, where you enter your callsign and
choose your preferences. It is recommended that you set up and use
FLDIGI normally in order to familiarize yourself with its use before
going on to utilize it for receiving SGARN transmissions. It is a
great program that will do a lot.

Use it to read the mail on PSK31 QSOs on 14.070 USB as a good way to
test your setup. Or better yet, use FLDIGI for a few PSK31 QSOs of
your own.

--- SGARN-specific setup recommendations for FLDIGI:

Be sure the RxID button in the upper right corner of the FLDIGI window
is check marked, and its green light is glowing.

Click on Configure, then click IDs. In the resulting window, change
the "Allow errors" box to 'Low', check only the "Disable freq change"
box, then click Save and close.

Disabling the automatic frequency change will prevent a new signal on
the waterfall from pulling you off-frequency in the middle of
receiving a file. It also means that you must click onto the SGARN
hamcast manually, but mode changes will still be automatic.

These settings help to ensure that the proper mode will be selected
automatically for your receiving station.



FLAMP:

Setup of FLAMP for receiving SGARN transmissions is more involved than
setting up FLDIGI - but not by much. It is still fairly simple.

In FLAMP, click the "Configure" tab for the Configure menu. Here you
enter your callsign and if you like, some brief info about your
station.

Below, there are a number of check-boxes, only one of which should be
checked: Check the box that says "Auto sync flamp to fldigi mode
selector"

This will cause FLAMP to automatically follow FLDIGI's advice as to
which mode to utilize, so that both programs work smoothly in concert.

No other box should be checked.

Now, just click the "Receive" tab at the top of the FLAMP window - and
assuming you already have FLDIGI running too, you are now ready to
receive the SGARN transmissions.

SGARN Multicast Reception:

>From here, it is assumed that you have a basic working knowledge of
FLDIGI, have the RxID activated, have FLAMP running and set up as
indicated above, and are tuned in to an ongoing SGARN multicast
transmission.

Times and frequencies for SGARN transmissions are listed here: SGARN
Servers and Schedules

They are also listed periodically on the NBEMS, fldigi-windows, and
linuxham Yahoo! e-groups.

When you first tune into an ongoing SGARN transmission, nothing much
will happen until the current file has been sent, and the next file to
be sent comes up to be transmitted. - At this time, a TxID will be
sent that FLDIGI will respond to by changing to that mode. The mode in
both FLDIGI and FLAMP will change to the proper mode, if they are not
already there. As the file information is received at your station,
your FLAMP "Recieve" tab screen will show the blanks being filled in
for the new file.

At this writing, the mode being used is MT63-500L. Note that MT63-500L
mode does not start to decode data for about ten seconds, but when it
does start decoding, it will be quite robust.

File, Date/Time, etc. will be filled in and as the first DATA
statement is received, you will see a block indicated in the FLAMP
Recieve "Blocks" pane. - You will also see data in the "DATA" pane
when the entire file is received with 100% accuracy.

After all of the blocks for a particular file are received, it will be
created on your system 100% accurate, and will show in the "Receive
Queue" pane.

When you click a file in the "Receive Queue" pane, you can choose
whether to SAVE or REMOVE it.

For SGARN use, ignore the "To TxQ" and "Report" buttons. SGARN does
not take or respond to reports, instead re-transmitting the files in a
continuous loop so that an unlimited number of stations can access and
use the data stream at any time. - If you miss a block on a particular
file, just leave it as it is and the next time that file is
transmitted, the block will most likely be filled.

The best system is to tune into a SGARN data stream and let it go
until all of the files are intact on your system, then save the files
and you are done for the day. Since the present SGARN multicast starts
at 0200 UTC and continues until 1100 UTC, it is recommended that you
let your system listen overnight, and then see what you have in the
morning.

At present the current ARRL bulletins, categories X,P,K,D,S and B are
being sent, along with brief SGARN bulletins in Text and HTML format.
As new ARRL bulletins are released, the SGARN files are updated so
that by receiving the SGARN transmissions, you will always have the
latest from ARRL HQ.

In the future, other content will be added. Check back here to see
what will be added. The PART97 restriction upon what may be
transmitted via multicast is that it be information "of interest to
amateurs". SGARN will be interpreting "of interest to amateurs" as
being information released by recognized amateur radio news and
information sources - not what somebody might want to get up on a
soap-box and rant about.

Signal reports are requested, and greatly appreciated. If you receive
a SGARN transmission, let us know about it by sending an eMail using
the address given in the SGARN bulletins.

Please see more in http://www.sgarn.org