I don't know if this is any help, but I wrote a vox recorder
program that runs under Linux and has been working well. It compiles
with gcc. Is there anything in Windows such as /dev/dsp? This is one
of the standard audio devices. It opens and closes like any file
except that when read from, it produces an endless stream of 8-bit
audio at 8,000 samples per second. When written to, it produces audio
in your sound card at 8,000 samples per second.
My program sits there, monitoring the sound card and looking
for samples that are either above or below the normal value for
silence which, in 8-bit audio is either 127 or 128. Usually, it kind
of hovers around 128 due to noise. When audio comes in, it opens an
output file called vx followed by numbers indicating the starting time
such as vx0410201121.raw. It just keeps adding to the file every time
there is more audio until you either kill the process or do a kill
-HUP which makes it close that file and start a new one.
If Windows doesn't have anything like /dev/dsp, then this
isn't going to help you. Also, the program puts itself in the
background when running. I am sure that Windows programs can do that
also, but I bet the mechanism isn't the same.
Mainly, I found that plus and minus 3 or 4 counts away from
silence is a good sensitivity level and about a quarter of a second
works well as a delay.
I am not familiar with programming in MS Windows, but the
concepts you have to deal with if you want to roll your own vox
program should be the same. You need to continuously receive the
audio stream from the sound card and only store the sound plus enough
delay to make speech sound fairly natural. One neat concept to keep
in mind is that the sampling rate is an excellent time base in your
program. If you want 8-k audio, 1/2 second = 4,000 samples of audio,
etc.
Martin McCormick WB5AGZ Stillwater, OK
OSU Information Technology Division Network Operations Group
Jeff Kenyon writes:
>Thanks Steve. Is there anyone out there that is using any other
>trunktracker software other then the BC245XLT's Interface? It is hard to
>get around because there is a visual representation of the keypad on your
>monitor, but it is useful for reading the radio's display when you want to
>know that unknown frequency or TG. I only use the 245 every now and then
>for monitoring Motorola type I or IIi hybrid systems and those are
>gradually being phased out in my area and everyone i either moving to at
>least type II or digital. I have found tt difficult to program in a type
>I fleet map on the BC250D and when reading the software manual for the
>E-scanner program it didn't impress me too much, and I think that the most
>I would do with the E-scanner program is just look at the dispaay if I
>can.
>
>
>
>
>
>On Tue, 19 Oct 2004, Steve Forst wrote:
>
>> Well, here is the link to the program I refered to:
>>
>> http://www.davee.com/scanrec/index.html
>>
>> It seems no different than any other windows sound recorder except that it
>> has a vox control. It would record audio from any source that has some sort
>> of audio output jack. I couldn't get to much out of it with jaws and if
>> everyone is using some other program for this purpose, I'd be happy to
>> hear about it.
>>
>> 73, Steve KW3A
>> ----- Original Message -----
>> From: "Jeff Kenyon" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Tuesday, October 19, 2004 3:19 PM
>> Subject: Re: Scanner recording
>>
>>
>> > Does anyone know how well this will work with JAWS, and what kinds of
>> > scanners it will work with I have a Uniden BC250D and a 245 and 235 and
>> > wouldn't mind recording some frequencies unattended.
>> >
>> >
>> >
>> >
>> >
>> > On Tue, 19 Oct 2004, Steve Forst wrote:
>> >
>> > > Hi Walt,
>> > > hope you're well. If you're talking about a tape recorder with vox,
>> that's
>> > > an option, but I'd rather stay within the pc. The Scanner Recorder
>> program
>> > > I saw would be perfect if I could get it to work. With the right
>> > > settings in the program it's supposed to do just what I want. Dont
>> want to
>> > > reinvent the wheel if something better is out there.
>> > >
>> > > 73, Steve KW3A
>> > > ----- Original Message -----
>> > > From: "Walt Sebastian" <[log in to unmask]>
>> > > To: <[log in to unmask]>
>> > > Sent: Tuesday, October 19, 2004 2:50 PM
>> > > Subject: Re: Scanner recording
>> > >
>> > >
>> > > > Hi ?Steve,
>> > > > How about a recorder with vox? 73.
>> > > > Walt
>> > > > WA4QXT
>> > > > Quaker Hill CT
>> > > > wa4qxt!myeastern.com
>> > > >
>> > > >
>> > > >
>> > >
>> >
>> >
>> >
>>
>
|
