Broadcast Equipment Recommendations

[dannas]

Hello, I would like to setup a live feed for my county. The current county feed has been unusable for a little over a week and even when it is online, there is a good bit of delay from the live audio via our local radios. As such, I was thinking that allowing users to connect directly to a feed instead of relaying it through Radio Reference might be a good local solution.

I have access to a datacenter facility with plenty of low-latency symmetrical bandwidth, redundant power, and static IPs to handle direct connections to the stream. Additionally, I already have server equipment in place that could run the recommended application.

Here is what I need help with:

1.) Best scanner system to buy that will follow the trunked system for Guilford County, NC. (dispatch, ops, and tac channels)
2.) Best server software to utilize for broadcasting
3.) Best client for smartphones (droid and iphone)

I would think that the only latency in the boradcast should be my Internet latency plus the smarthphones network latency which should really be less than a second total delay for the audio feed of the devices can simply connect directly to the server. This would be a huge benefit for volunteers relying on this audio feed.

Any help is greatly appreciated.

 

[kb8zxe]

I will throw my 2 cents worth in.

As far as delay goes it really has nothing to do with Broadcastify. It has to do with the MP3 encoding. The delay is from the device encoding the audio into MP3. The Broadcastify servers may only add a few hundred milliseconds to the delay. MP3 was designed to buffer to prevent hick ups when the internet link was not perfect. With radio we don't care if we lose a split second of audio, as long as it comes right back.

Clients never connect directly to the MP3 audio encoder. The MP3 encoder connects to an MP3 server such as Icecast, clients then connect to that. Both programs may be running on the same server so it can be a bit confusing. If you choose to go with MP3 whether you use Broadcastify or not you can tweek settings to reduce delay. The standard for MP3 streaming in my opinion is Darkice as an MP3 encoder and Icecast as an MP3 client server.

You have a valid point with so many agencies going digital and responders not being able to hear anything after the initial call on the pager. I am on a local fire dept so I am in the same boat.

Two solutions come to mind. First would be to use a different protocol, such as SIP. No buffering is done in SIP and is darn near real time. This would require some APPS written for smart phones. This is actually a solution that could be deployed all over the country. You could even have it auto start on your phone if you use something like CADPAGE.

Second would be to create your own patch to VHF or UHF and have the responders listen on a radio. You would have to get a frequency to use and set some type of interface up. The dispatch center and county should provide this service but I know it's not happening in a lot of places. I have a friend who has tried this and it works well. Of course you would need to get the okay of the dispatch center and that may not happen. In theory this would be the easier way to go but there is always red tape with things like this.

Since this applies to my agency too I will continue to look into the SIP solution.

Bob

 

[dannas]

SIP... now we are talking

kb8zxe, I didn't think about the transcoding delay; however, I am very familiar with SIP as I work for a VoIP provider. We could even use something like open source asterisk and simply setup a conference room that the scanner would output to 24x7. Users could dial into the conference room via the PSTN and access the feed with no software installed or we could simply create a SIP registration and they could register to the asterisk server using one of many open source softphone clients on their droid, iphone, or PC. This would allow them to dial the conference room extension and we would not incur any toll charges to provide the service.

Furthermore, I could centrally host the conference rooms and create one for each feed. You would simply speed dial the conference room number that you wanted to drop into. Likewise, we could have folks stream their local feed using something like an ATA registered to the system and let them moderate the conference/stream that they were responsible for hosting.

Now the side I am not very familiar with is the scanner side/programming. Is there a scanner that you would recommend that would be capable of picking up all of the repeated/trunked tac channels? I was looking at something like the BCD536HP from Uniden. Is there a better option? Does anyone make a scanner that is a USB or PCI card since we'll likely be feeding this into a server anyway?

 

[kb8zxe]

Asterisk would be a great idea. This would also allow the few people out there that don't have smart phones to listen. It could also allow them to talk to each other if you didn't mute the audio.

Let me do some thinking, I may want to give this a shot.

 

[dannas]

I have this working and have had it in service for our department for a little over a week now. It seems to be a great solution and very easy for our members to use. I ended up getting the BCD536HP scanner and have been pretty happy with that thus far as well. I'm putting a few finishing touches on the solution but will soon offer it to other departments as well.