VoIP, setting up the equipment-Basics

FMROB · Post by **FMROB** » Thu Apr 01, 2004 8:01 pm

Hi all.
Here is my question, maybe a user of this type of equipment could answer. My buddy lives about 18 mi. away. I work where he lives and I need to hear low band portable traffic from where I live, which I currently can't do...So here is what I propose.

I would like to setup a lowband maxtrac as a reciever only at his house, and be able to hear the low band traffic at my house via a uhf maxtrac transmitter at my house (at very, very low power) so I can hear it on my portable. I would like to link this project via the VOIP stuff.

I looked at the IRLP stuff, and echo link...How does it all go together?
I noticed that the IRLP works on linux, I would prefer a windows base.
Is the hardware easy to interface to the maxtrac radio?
What software should I use to run this?

Any real basic help from a user would be great.....

d119 · Post by **d119** » Fri Apr 02, 2004 2:06 am

I don't think either setup is really going to help you unless it's amateur traffic you want to relay.

Not knowing anything about IRLP, I can't really comment on it. However, with EchoLink, your callsign is registered and verified before you are granted access to the network.

There is a VoIP interface that connects between the radio and the PC that handles all the signalling - COS, PTT, Receive Audio, Transmit Audio. It generally consists of a box with a serial interface on it, and earphone-type jacks that your TX Audio, RX Audio, COS, PTT, etc. plug into. There are several different companies that manufacture these interfaces (also known as "Rig-to-Soundcard" interfaces). Several of them are listed as compatible with Echolink. I use the unit manufactured by DRF Technologies. I have no idea what IRLP's interface looks like.

You could try just running a streaming audio server at the location that's within range of the lowband traffic, and use a PC at your house to listen to that streaming audio with some sort of VOX unit attached to your low-power UHF radio that keys it up when traffic is heard.

Like I said, unless it's Amateur stuff, I'd stay away from EchoLink. Again, I don't know about IRLP so I don't know if you can use it for commercial purposes (which I am assuming is what you are wanting to listen to, though I could be and probably am mistaken).

Thanks and good luck.

D119

FMROB · Post by **FMROB** » Fri Apr 02, 2004 5:03 pm

Thankyou for the reply,,,,But what I am really looking for is someone that actually uses this stuff for a quazi-commercial application. I am not a ham, nor do I want to use any service associated with the amateaur radio stuff. I saw the echolink site, and the verification for a valid license.

I would assume there is some sort of program that allows this type of use from computer user to computer user...no middle man so to speak. I just want to set the equipment up and run the two computers over the high speed internet (if possible)....

If someone has any insight on this please let me know... Thanks, Rob

ASTROMODAT · Post by **ASTROMODAT** » Sat Apr 03, 2004 7:13 pm

DVSI has a very nice VoIP box that will do the job quite nicely. You'll need a box at each end.

Larry

kc2eus · Post by **kc2eus** » Sat Apr 10, 2004 9:44 am

ASTROMODAT wrote:DVSI has a very nice VoIP box that will do the job quite nicely. You'll need a box at each end.

Larry

IRLP also produces a commercial version of the software. http://www.irlp.net mentions they have installed versions for commercial applications.

Andrew
KC2EUS

ASTROMODAT · Post by **ASTROMODAT** » Sat Apr 10, 2004 4:48 pm

The DVSI box is a lot more than just software. Quite pricey, though. Works very nice! Unlike IRLP and other Ham VoIP products, the DVSI box is a complete stand alone unit (e.g./, you do not need a PC attached with a sound card, etc.).

Larry

kb4mdz · Post by **kb4mdz** » Sat Apr 10, 2004 8:09 pm

Look at the JPS NXU-2; http://www.jps.com Neat boxes, I've been involved in a project with them, but only from the 'hook this wire here, program these settings' aspect; not the theory, so I'm not sure about what's behind them. I think they're a proprietary coding or something, so they'll be secure enough.

TX Audio, RX Audio, and maybe PTT & COR depending on your application. Forget some of the details.

Work pretty well.

Chuk G.

ASTROMODAT · Post by **ASTROMODAT** » Sat Apr 10, 2004 9:56 pm

The problem with the NXU-2 is the same issue that virtually all other such analog systems have when interworking with P25 radios in the digital (IMBE) mode: Double Vocoding.

For old analog FM technology radios, this is less of an issue since the voice channel is analog. With P25 IMBE radios operating in the digital IMBE mode, there is NO need to D/A and A/D over the internet. DVSI's VoIP box streams the IMBE audio directly over the Internet in VoIP mode, so double vocoding is avoided.

The DVSI VoIP box is the only unit I am aware of (at this time) that supports direct VoIP with IMBE, and thus avoids the double vocoding of all these other systems, whether it's the JPS box, IRLP, etc.

The only problem with the DVSI VoIP box is that you can not tie it into the DIU's MRTI port, since that is analog and would then entail double vocoding for IMBE ops. Yoiu have to catch the IMBE audio inside of the DIU3000, ahead of the MRTI port, and run this digital path to the DVSI box, where it is then streamed for transmission over the internet.

Larry

Quarterwave · Post by **Quarterwave** » Wed Apr 21, 2004 11:37 am

Since in this configuration the UHF transmitter on your end would require a license anyway, why don't you just set up a uni-directional cross band repeater (VHF Lo in = UHF out) at your buddies place and use a Yagi for transmit pointed your direction? Same amount of radio equipment less one power supply, no IP equipment or service, the radios (Maxtrac or Radius) only need a 4 conductor cable to do this (16p to 16P or a 16P to Mic Port). If you only need it to be one during certain hours - put it on a timer. Alot of fire dept's I know of have some form of this in service until they completely switch systems over to UHF or 800.

ASTROMODAT · Post by **ASTROMODAT** » Wed Apr 21, 2004 11:41 am

NextTel DirectConnect will work fine.

Larry