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Setting up your Broadcasting Station

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Revision as of 14:16, 14 January 2010 by Bote (talk | contribs) (→‎Related Links: add Orban VU meter for PC)

There may be other methods but these instructions will work and provide a good quality feed.

These instructions assume that the feed owner has a standard computer card with stereo 1/8’ mini connectors and a radio with a mono 1/8’ mini connector for the headphone output.

Introduction

To set up a streaming scanner audio feed on the Internet you must pay attention to a number of things, but once these are done properly you can sit back and enjoy, along with all your adoring listeners.

You will:

  • Buy the proper audio and data cables to go between your scanner radio and your streaming audio computer.
  • Program your scanner to allow audio to flow to the Rec or Tape Out jack, if available.
  • Connect all the cables and adapters.
  • Configure your streaming audio software.
  • Set the audio levels properly for the best sounding feed possible.

Hardware Connections

There are two basic setups
  • A mono feed using a single radio
  • A stereo feed using two radios as follows:
    • One radio for the left side audio
    • One radio for the right side audio

For a Mono Feed (One Scanner)

Simple Method

You will need a cable with 1/8 inch (3.5mm) plugs on both ends, either stereo or mono will do fine. These can be purchased from various sites on the Internet or you can usually find them in stock at your local Radio Shack store, but check their web site for availability first.

Procure ONE of the following cables that best fits your specific needs.

  • RS #42-2497 - 1 Foot Long Shielded Stereo Cable; for installations where the scanner is close to the streaming computer
  • RS #42-2387 - 6 Foot Long Shielded Stereo Cable; for installations where the scanner is mounted away from the streaming computer
  • RS #42-2420 - 6 Foot Long Shielded Mono Cable; if above is not available

Follow these steps for connecting your scanner to the streaming audio computer:

  • Plug one end of the patch cable into the Line Out, Rec, or Tape Out jack (recommended) or else Headphone jack of your scanner.
  • Plug the other end of the patch cable into the blue Line In (recommended) or red Mic In jack of your streaming computer sound card.
  • Proceed to #Serial Data Connection

Universal Method

Procure the following cables. You will end up with two separate pieces that you will plug together to form one unit.

  • RS #42-2542 - 6 Inch Long Mono Y-Cable; "Cable A" ...OR...
    • RS #274-269 or #274-369 - alternative Y-adapter if above is not available; "Cable A"
  • RS #42-495 - 6 foot Y-cable, 1/8 inch plug to RCA phono plugs; connects to your computer Line In jack; "Cable B"

Follow these steps for connecting your scanner to the streaming audio computer:

  • Plug the 1/8 inch mono plug of Cable A into the radio's Line Out, Rec, or Tape Out jack or else the Headphone jack.
  • Plug the 1/8 inch stereo plug of the “Y” Cable B (42-495) into the streaming computer Line In (blue jack) or else Mic In (red jack).
  • Connect either RCA female of Cable A to the left (white) RCA plug of Cable B (42-495). The red is not used for mono feeds.
  • If you use the audio isolator, insert it between Cable A and Cable B.
  • Proceed to #Serial Data Connection

For a Stereo Feed (Two Scanners)

Procure the following cables. You will end up with three separate pieces that you will plug together to form one split Y-cable.

  • 2 x RS #42-2542 - 6 Inch Long Mono Y-Cable; "Cable A" ...OR...
    • 2 x RS #274-269 or #274-369 - alternative Y-adapter if above is not available; "Cable A"
  • RS #42-495 - 6 foot Y-cable, 1/8 inch plug to RCA phono plugs; connects to your computer Line In jack; "Cable B"
  • Plug the 1/8 inch mono plug of Cable A into radio #1's Line Out, Rec, or Tape Out jack or else the Headphone jack.
  • Plug the 1/8 inch mono plug of the other Cable A into radio #2's Line Out, Rec, or Tape Out jack or else the Headphone jack.
  • Plug the 1/8 inch stereo plug of the “Y” Cable B (42-495) into the streaming computer Line In (blue jack) or else Mic In (red jack).
  • Connect either RCA female of Cable A from radio #1 to the left (white) RCA plug of Cable B (42-495).
  • Connect either RCA female of Cable A from radio #2 to the right (red) RCA plug of Cable B (42-495).
  • If you use the audio isolator, insert it between both Cables A and Cable B, observing the correct left/right markings.
  • Proceed to #Serial Data Connection

Serial Data Connection

It is highly desirable to send the channel tags from your scanner along with the audio stream so that listeners know what they are hearing. If your scanner provides a serial data interface and you use the proper software on your streaming computer, you can add this channel tag data and greatly improve your feed.

For the Uniden BCD996T scanners you can use the cable that came with the scanner to connect from the mini-USB connector on the front of the scanner to the DB-9 on your computer, or you can use a traditional DB-9F to DB-9F cable from the rear of the scanner. The BC780XLT has a DB-9F on its rear apron, so you will need a cable with a DB-9M on one end to connect to the scanner and a DB-9F on the other end to connect to the computer.

If your computer has only USB ports, you can buy an inexpensive converter that provides a DB-9M connector for older serial cables. Install the driver software provided with the converter and select a COM port that is compatible with your streaming software. Then configure the streaming software for the same COM port that connects to the scanner. ScannerCast can talk directly to the BCD996T scanners. Talkgroup Monitor can talk to both BCD996T and BC780XLT scanners, but is more complex to set up.

Software Configuration and Audio Levels

Computer Audio Mixer Settings

Ideally you should use the streaming computer's Line Input since this more closely matches the audio level from your scanner.

If you only have a Mic Input:

  • Open the mixer software on your computer
  • Go to Recording properties
  • Look in Advanced Settings for a check box labeled "Microphone boost" or "20dB boost" or similar
  • Make sure that the boost check box is cleared since you do not want to amplify the strong audio from the scanner any more than it already is!

NEVER exceed 0dB level on your stream or it will sound distorted and awful, so people will not want to listen to it. Red-lining is no good at all for digital audio.

Measure the audio level from your scanner(s) by opening any sound processing software on your computer that has an audio meter display, such as SoundForge, Total Recorder, Audacity, or simply use the excellent Audio Level Meter PC software that displays the sound card input levels on screen.

  1. To set the proper audio level for your scanner stream, set your scanner to the local NOAA weather radio broadcast since they provide continuous transmissions. If they have particularly quiet audio or can not be received at your location, go to a conventional radio channel in the scanner and open the squelch to receive white noise.
  2. If you were forced to use the scanner's Headphone jack, adjust the scanner's volume control to between 1/4 (one-quarter) to 1/2 (one-half) volume level, no higher. You don't want to overload your sound card and potentially blow it up! Note the position of the volume knob in case it gets bumped in the future; you can make a mark on both the knob and the scanner housing to reset it quickly. Using the scanner's Line Out eliminates all this mess.
  3. Now that you have some audio coming from your scanner, adjust the Recording mixer control associated with your scanner input until the audio level meters peak around -3dB or so, NEVER let the peak indications hover around 0dB or your feed will sound crappy and nobody will listen to it. Most of the audio peaks should pop up to -3dB or -2dB on occasion, while the rest of the audio signal should fall significantly lower than this.
  4. Set your scanner to scan its normal scan list and listen to your stream under actual program conditions to ensure that you have configured it properly. Don't hesitate to tweak it to perfection, as nothing about this is plug-and-play! Just make sure never to exceed 0dB and you should do fine.
  5. If your stream has two scanners, then repeat the process for the second scanner and give it a test listen.

If you are certain that your hardware connections are correct and you don't get any indication of audio, go to your software mixer controls in the Recording settings to ensure that you have selected the input control matching the hardware input where the scanner is plugged in. If you plugged the scanner into the Line In, then the mixer must have a check box ticked in the Line In column.

Streaming Software Settings

ScannerCast will automatically retrieve the feed settings from Radio Reference once you identify your feed to the software.

Other packages such as SimpleCast, ProScan, Windows Media Encoder, and others should use the following settings for best results. For one scanner:

  • Channels = Mono
  • Bit rate = 16kbps
  • Sample rate = 22kHz
  • Format = MP3

For two scanners:

  • Channels = Stereo
  • Bit rate = 32kbps
  • Sample rate = 22kHz
  • Format = MP3

Configure the streaming software to use the correct sound card input. This is especially important if you have multiple streams running from one computer with multiple sound cards.

Notes

The typical radio output will be an 1/8 inch mono jack. Always use the Line Out, Record Out, or Tape Out when available on the scanner. This provides a constant audio level to the streaming computer and allows you to listen to the scanner's local speaker whenever you wish. Failing that, use the Headphone jack, not the speaker output. You can monitor your scanner via the streaming computer's speakers.

The typical computer sound card input will be an 1/8 inch stereo jack. The Line Input is desirable and is usually color-coded blue. Some computers, particularly laptops, only provide a Mic Input and this is usually color coded red.

Line output of the radio to line input on the computer is the best connection as this gives the cleanest audio and still allows you to listen to the scanner on its local speaker. Once you set the audio level, you don't have to touch it again since the volume control does not affect the line output.

Uniden scanners must be programmed properly so that each channel is set to Record = ON to allow audio to flow to the Rec or Tape Out jack. If you skip this step, the feed will not get audio from the scanner on those channels.

Newer Uniden scanners label the line output “Rec” (for Record out) and is located on the rear of the radio and is color coded green. The Record output needs to be turned ON via the software to activate it for use.

If you need to connect the headphone output of the radio to Mic in on the computer you will need to watch your audio levels on both the radio and computer. It is very easy to overdrive the audio.

Avoid using the speaker output of the radio because the output level maybe too high for the computer input and cause distortion. If this is all you have, keep the volume level low, between 1/4 to 1/2 volume.

The use of an audio isolator can help to eliminate hum between radio and computer due to different a.c. power grounds. Radio Shack has an isolator listed in #Related Links. It is an audio transformer that blocks d.c. continuity between the scanner housing and the computer case.

Monitor the desired frequencies to ensure that the scanner does not receive radio interference from computers and computerized equipment nearby. If necessary, move the scanner around or re-orient the power, audio, and data cables to avoid picking up stray radio energy from devices in your shack. You'd be surprised how dirty some devices are.

Scanner to Computer connection 12-04-09.jpg

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