Southeastern Asterisk Radio Networks

Archive for September, 2007

Emergency Operations – Regulations

Sep 20

Posted by OPS in Communications, Emergency Response | No Comments

Emergency Operations – Regulations regarding radio communications.

A station in, or within 50 nautical miles of Alaska may transmit emissions J3E and R3E on the channel at 5.1675 MHz (assigned frequency 5.1689 MHz) for emergency communications. The channel must be shared with stations licensed in the Alaska-Private Fixed Service. The transmitter power must not exceed 150 W PEP. A station in, or within 92.6 km of, Alaska may transmit communications for tests and training drills necessary to ensure the establishment, operation, and maintenance of emergency communication systems.
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Asterisk app_rpt via USB

Sep 17

Posted by OPS in Asterisk, Asterisk RF, Communications, RF Gateways, Repeater Controllers | Comments off

A new low-cost way to interface Asterisk app_rpt to radio can now be used with a USB sound adapter. Some modifications are needed to bring out the PTT, block DC on the audio outputs, and attenuate the receive audio to match the microphone levels.
A new low-cost way to interface Asterisk app_rpt to radio can now be used with a USB sound adapter.
Some modifications are needed to bring out the PTT, block DC on the audio outputs, and attenuate the
receive audio to match the microphone levels.

From the qrvc.com web site the following features are mentioned:

chan_usb radio contains all of the interface code to interface app_rpt to a CM108 based USB sound fob.
In addition it contains DSP code to do CTCSS encoding and decoding, squelch, pre-emphasis and soft
limiting, de-emphasis, and audio level adjustments.

Basically, you only need to make 3 or 4 connections to your radio:

  • Discriminator audio, de-emphasized audio, or speaker audio.
  • Transmit audio (direct to modulator, or microphone)
  • PTT

A new doorway is quickly opening to continue the progression of Asterisk as the way to interconnectivity.

For more details about Asterisk app_rpt visit http://app-rpt.qrvc.com/

and information about Asterisk can be found at http://www.asterisk.org

ALE On-The-Air Week

Sep 12

Posted by OPS in Communications | No Comments

ALE On-The-Air Week
05-15 October AOTAW-2007
START:
0001 UTC 05 October 2007 Friday
END:
2359 UTC 15 October 2007 Monday

HFLINK sponsors this annual International Amateur Radio event.

All ham radio operators worldwide are invited to participate in 10 days of HF Automatic Link Establishment activity on the air. “AOTAW” is an open operating event for hams to explore ALE communications and equipment. The experience gained by operator participation in this readiness exercise is useful for HF Emergency/Disaster Relief communications.

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What are FXS & FXO?

Sep 5

Posted by OPS in Asterisk, Asterisk RF, Resources | No Comments

What are FXS & FXO?

FXS — Foreign Exchange Station

FXO — Foreign Exchange Office

An FXS device initiates and sends ringing voltage. FXS sends the voltage to an FXO device, which receives it.

Pitch Catch

The phone receiving the call is the last FXO device in the chain, and when it receives voltage from an FXS device, the phone will ring.

Connect the outside line to an FXO port on your Asterisk server to receive voltage from the outside lines.

Connect the phones to FXS ports on your Asterisk server. When the FXO module in your Asterisk Server receives the voltage, it will then generate voltage using the FXS module and send it to your analog phone.

CO PBX Phone

Hint: Remember the “to”… FXS = FX(to)Station and FXO = FX(to)Office.
       With “to” representing the direction taken by the signal.

PSKmail – Another Emergency Response Tool

Sep 4

Posted by OPS in Communications, Emergency Response | No Comments

PSKmail as described on http://pskmail.wikispaces.com/

PSKmail is a narrow band mail delivery system for use by amateur radio hams via short wave (HF) communication. It is only available for Linux (it is time to change to Linux anyway…). Unlike PACTOR, it does not use a special controller, you just need a computer with a sound card. PSKmail uses Fldigi in PSK125 mode.

PSKmail has a client/server architecture. Unlike Packet Radio (Q15X25) the PSKmail protocol only allows 1 connected client at the time. Bandwidth (3dB) is 129 Hz!!!

The PSKmail client is written in GTK2 perl. At this moment the applications is a Mailbox (port 24) allowing down/upload of mail from the internet, and downloading information from the web (ASCII text only), position update and station-to-station messaging via APRS(port26) and chat mode (TTY, port 87).

Version 0.4 has enhancements for emergency communications. This means that even if the internet backbone is down, you will still be able to send messages and files from client to client.

Pskmail now also works together with EVOLUTION and other Linux mail clients. You can then use the mail integrator you are used to (any mbox compatible system).

There’s a PSKLive (LiveCD) available to test with. The LiveCD allows one to operate the programs without accessing the hard drive on their computer.

As for Technicians … the 10m Band is the place we can use PSKmail on HF.

28.000 – 28.300 MHz: CW, RTTY/Data–
Maximum power 200 watts PEP

Be interesting to find out what kind of coverage is available.

Interview Audio Regarding PSKmail