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SGARN HF Multicast SYSOP Guide
« on: September 17, 2013, 05:04:09 PM »
SGARN HF Multicast SYSOP Guide

Mission and Philosophy:

The Second Generation Amateur Radio Network (SGARN) is an attempt to build a global, all-amateur radio network that will succeed where the Packet network failed, by avoiding the miscalculations which affected the Packet network so adversely.

See the article "SGARN Basics and Philosophy" elsewhere in the SGARN section here at USPacket to see the big picture. Here the discussion is narrowed down to the HF section of the SGARN network, and how to participate as the SYSOP of one of the HF multicast servers.

The SGARN HF network is a self-organizing multicast network, generating data streams that an unlimited number of amateurs can tap into at any time to receive the latest information of interest to amateurs. The information will come from recognized and respected sources, not some fellow ranting on a soap-box, and the SGARN multicast network model has a reasonable expectation to achieve wider coverage than the old Packet net at its peak, by several orders of magnitude. Global coverage is not an unreasonable goal for a self-organized multicast streaming data network.

Apart from amateur radio operators, no other group has a reasonable expectation to build and maintain an independent global information network. This is our unique privilege and challenge as hams.

This guide is set up in sections, covering first the software, then the equipment, then at last an operation and content guide.

Read the whole thing.


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

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


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 Server (transmitting) 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 transmit the SGARN multicasts.


You may already be using FLDIGI, as it is the most popular digital multimode program for amateurs at this writing. You will need a ham radio soundcard interface which connects your computer and radio together and operates the Radio's push-to-talk or activates its VOX so that you can transmit data.

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 originating SGARN multicast transmissions. It is a great program that will do a lot.

To get started and to verify that your setup is working properly, use FLDIGI for a few PSK31 QSOs at 14.070 USB, the PSK31 watering hole.

This is good practice, as SGARN servers also operate within a watering hole type environment, so that amateurs know where to look for the data streams and can choose the one that they can receive best from their location.

To begin the SGARN-specific setup of FLDIGI, click the "TxID" button at the top of the FLDIGI screen, so that your station will automatically send TxID transmissions. When the TxID button has a green light, TxID is activated.

Now, under the "Configure" menu item, choose the "IDs" section, then check the "End of xmt ID" box at the bottom right.


Setup of FLAMP for SGARN transmissions is just as easy as setting up FLDIGI for them.

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

Below, there are a number of check-boxes, only two of which should be checked: Check the box that says "Auto sync fldigi to flamp mode selector", and check "Change fldigi mode just prior to transmit".

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

No other box should be checked.


Whatever kind of radio and equipment you use, you will be making long, continuous transmissions. The enemy here is heat build-up, which can damage your radio if you do not monitor and control it carefully.

I have been experimenting with HF multicast for close to twenty years, and until recently I was the only amateur who had ever done so. In all of this time I have never damaged or destroyed a radio, all because of a few simple precautions that I have followed.

I have used solid-state radios ( Usually a Kenwood TS-450sat ) and have developed a rule of thumb for these...

* Grasping the heat-sink on the back of the rig firmly, if it is too hot for my hand, it's also too hot for the radio.

By following this one standard faithfully, I have never damaged a radio.

Reach back there and check often, especially whenever you change anything or try something new. ( New mode, new antenna, new cooling fan, new frequency, etc. )

I check every five minutes for the first half hour, and every half-hour or so thereafter. I have found that usually it will be as warm as it is going to get after a half-hour of transmitting, but if you have nothing better to do, it never hurts to check it again, every once in a while.

-- Heat Reduction Strategies:

The primary heat-reduction strategy is to keep the power down. On my 100 watt TS-450sat, I never run more than 25 watts while making a multicast transmission, and quite often I run 20 watts if trying a new mode, frequency etc..

Your radio may run cooler or hotter than mine. Remember that if you firmly grasp and hold the heat sink and it is uncomfortable for you, then it is probably uncomfortable for the radio too.

A good general rule of thumb here is to be sure that your radio is well-ventilated, not crammed in a tight space. Use 2" sections of 1" PVC pipe over the feet to get it up off of the desk-top. Make sure there is plenty of room around at the back, and use a small fan to keep a constant movement of air over the heat-sink.

Be certain that your antenna is resonant, and that reflected power is kept as close to zero as you can get it. Reflected power is a heat source that you can minimize or eliminate.

Run the radio in a cool area.

Your first reaction to the radio getting too hot should be to either stop transmitting or reduce power while you check to see what might be wrong.

This is how I have managed to do this for decades without damaging or frying a rig.


This section assumes that you have the software set up, your radio set up for continuous operation, preferably with a small fan blowing across the heat-sink, your antenna tuned on your frequency of choice and you are ready for your first multicast transmission.

--- Content:

SGARN policy is to only send news and information of interest to amateurs, originating from established, respected sources. That generally means the various ARRL bulletins, an HTML version of Southgate Radio News eMails, AMSAT bulletins, etc..

No soap-box BS. - Save all of that for the internet, this is ham radio.

It is recommended that you start with the ARRL bulletins, which will generally add up to 20-30kb. - If you try to send much more than that with a digital mode that will not fry your rig at 25 watts output, it will take so long for all of it to be sent - and then sent again so that recipients can get fill-ins on blocks that they may have missed - that you will defeat the error-detection and correction feature of Amateur Multicast protocol. (AMP)

In general, faster modes are wider, and wider modes generate more heat build-up. Lately I have been using Domino X22 to good effect. It is reasonably fast without being so bad about generating heat as many of the other digital modes. Experimenting with various digital modes is encouraged, but if you start off with DOMX22 you won't go far wrong.

Choose DOMX22 in the FLAMP "Transmit" tab and it will automatically change FLDIGI over to DOMX22 as well.

The idea here is to send a stream of data that amateurs can tap into at any time, not on a particular schedule, and within a reasonable amount of time get all of the data being sent, and get fills where necessary for 100% accurate copy of that data.

You can get the files by listening to another SGARN server if you have no internet, or you can get them via eMail from the ARRL, Southgate Amateur Radio News, etc.. W1AW is not a good source because errors will creep in, even if you usually get good copy. There is no error detection or correction for the W1AW transmissions so any kind of interference will result in garbled reception.

Convert from email to Text or HTML files, and put the files to be sent in the FLAMP Tx folder. If you choose the FILE menu item in FLAMP, then choose FOLDERS, you will see the Tx folder in there. Go to the FLAMP Tx folder and right-click it for its properties. That should show its location in your computer. Make a shortcut on your desktop, as you will be updating the files in there regularly.

In addition to the bulletins, include a brief text file that has information about your station and SGARN. - I send a text and an HTML version of this file, mixed in with the bulletins.

-- Transmission Setup:

Now your software is set up, your radio is set up, your files are waiting in the FLAMP Tx folder, and you are ready for the final setup before transmitting.

First check to be sure that in FLDIGI, the "TxID" button at the top is turned on and green.

In FLAMP, Click the "Transmit" tab. There are number of settings here that I will recommend. - Start off with my recommendations, but do not hesitate to experiment with them later.

Blk size: 128

Xmt Rpt: 1

Hdr Rpt: 1

Comp: base64 and check the Comp box for bulletins, but not for your brief Station Info text files so that hams can "read the mail" on those.

Now click the "Add" button and it will display the FLAMP Tx folder. Choose a file, and it will appear in the "Transmit Queue" pane at the bottom of the FLAMP window. Keep adding files in the order that you want them to transmit until you are done.

On longer files, do not forget to check the "Comp" box.

Before making any transmission, check to be sure the frequency is clear on the waterfall. If there is activity in your preferred spot either move over a bit,  or just wait until the frequency is clear.

When you are ready to start transmitting, go to FLDIGI, click the "Tune" button at the top and adjust your rig for 20-25 watts output with no ALC action.

Now go back to FLAMP, click the "Events" tab, make sure the "Continuous repeat of transmission" box is checked, and click "Start Events" to begin the transmission.

-- Stop Transmission:

Under the FLAMP "Events" tab, click "Stop Events" at the bottom, then under the "Transmit" tab, click the "Cancel" button. This will cause FLDIGI/FLAMP to gracefully end the transmission within about ten seconds or so.

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« Last Edit: September 19, 2013, 05:53:48 PM by USPacket »