Scanner Audio Out to Cell Phone Headset Audio In

[Renegade631]

I thought this would be a lot simpler than it is turning out to be...

I want to be able to listen to my scanner, over the phone, so I need not be carrying it around all the time but can call in when I want to listen.

I have a spare cell phone with auto answer, and thought I could maybe just cut off one ear of some headphones, and the microphone off a cell phone headset and connect them, not so simple, it did nothing.

I'm speaking of a wired headset of course, I read a similar thread about someone using bluetooth that might fit my application, but I'd rather not spend that much money, and of course bluetooth will have battery life limitations.

Any ideas?

[KI6ABZ]

This won't work well because the microphone-level input for your cell phone is MUCH higher than the audio level your scanner puts out.

Have you considered setting up a streaming audio server? Products like Shoutcast and Windows Media Encoder are free and let you set up a much higher quality stream than a telephone; you can plug your scanner's headphone output in to your computer's line in jack.

If you really want to use the phone, you can patch your cable through something like this to lower the audio level down to something that won't overdrive your cell phone's mic input: Gold-Plated Volume Control Cable for Stereo Headphones - RadioShack.com

[Renegade631]

Originally Posted by KI6ABZ

This won't work well because the microphone-level input for your cell phone is MUCH higher than the audio level your scanner puts out.

Have you considered setting up a streaming audio server? Products like Shoutcast and Windows Media Encoder are free and let you set up a much higher quality stream than a telephone; you can plug your scanner's headphone output in to your computer's line in jack.

If you really want to use the phone, you can patch your cable through something like this to lower the audio level down to something that won't overdrive your cell phone's mic input: Gold-Plated Volume Control Cable for Stereo Headphones - RadioShack.com

Thanks for the input.

I already have shoutcast installed, listening via internet is a non-issue, I can do it at will and have done it a few times. The goal here is so that I may call in at will from my phone.

My cell phone can't pick up a shoutcast feed (Motorola RAZR V3m)

As far as the volume controlling part you linked to, my headphones actually have a volume control on them already, and if I turn it, and the volume up on my scanner I can hear it just a little bit, turning it down gives me nothing at all.

Thanks in advance for any further feedback on the subject.

[Renegade631]

Made a little progress...

Both the headphones I had, and the headset I ripped apart had those thin braided sorta wires with like thread inside (you know what I mean?).

I found the mini-usb adapter for the wired headset, cracked it open.
I also found an extension cable for a microphone I had, cut one end off and stripped the wires.

I attached the wires to (alligator clips for now, will solder later when it works right) then to where the jack for the headset plugged into the min-USB adapter.

Now I can hear but it is very distorted, lowering the volume only makes it harder to hear.

I was reading into putting a discriminator cap on, and I'm thinking if I put a 10k ohm resistor in line, it may do the trick.

I'll update this thread when I find one.

[Renegade631]

Photo of current rig attached

[davidmc36]

Couldn't you just do like a Red Green type of setup and tape (for experimenting) the cell phone with the mic right on top of the speaker of the scanner? If it was that close I would think it should work. Then when you get the volume right, make a little mount that they slide into to marry them up.

[davidmc36]

Originally Posted by davidmc36

Couldn't you just do like a Red Green type of setup and tape (for experimenting) the cell phone with the mic right on top of the speaker of the scanner? If it was that close I would think it should work. Then when you get the volume right, make a little mount that they slide into to marry them up.

This works quite well actually. Had to space the mic a half inch or so from the speaker. Audio is pretty clear.

[Renegade631]

I did something like that, and it works ok. Just not quite geeky enough

[davidmc36]

Originally Posted by Renegade631

I did something like that, and it works ok. Just not quite geeky enough

I'm with ya there!

http://www.radioreference.com/forums...ml#post1061489

[scansalot52]

Bluetooth for both scanner and cell phone?

[daveMICU]

To match the audio from your scanner to your phone without distortion, you first need to properly load the audio amplifier from your scanner. This can be done by using an 8-ohm power resistor across the audio output from the scanner (rated for the output power of your scanner's audio amplifier), or use an audio transformer which usually has an 8-ohn primary and a 600-1000 ohm secondary (usually center-tapped for feedback when designing oscillator/amp circuits). The audio must then be fed thru a couple of resistors or a variable resistor "pot". The circuit might look something like this...

IN ------R-----------POT
..........R...........POT------------------- OUT
..........R...........POT
IN ------R-----------POT------------------- OUT

(ignore the dots...)

R is an 8 ohm resistor and the POT is a 10k ohn variable resistor

This will allow you to properly adjust the audio levels to match your cellphone without causing clipping or over-modulation of the signal.

Good luck!

-Dave

[firetaz834]

I was going to suggest that if your phone had internet access then you could access your shoutcast to listen to your scanner. Your install looks intriguing, just thought I would throw that out.

[load_nikon]

I ran into this about the same time as the OP posted but solved it and went a little farther for about $10 at radio shack. I was actually trying to create a super cheap, low tech interoperability solution for our Fire Department. Initially I wanted to connect a radio to a cell phone. Then to a laptop for recording and playback on air. The only thing required that the high-end interoperability hardware already had built in was someone to key the mike.

A 3.5mm to 3.5mm male to male stereo audio cable paired with
a 3.5mm to 2.5mm adapter connected radio to phone.


A 3.5mm stereo female to dual 3.5mm mono female connected radio to laptop.

Not like we'll be transmitting in stereo anyway. Also note, cannot connect all three... yet.

Just a quick patch to record fireground or dispatch radio traffic to mp3 (which makes for very disorenting ringtones) or to listen to local radio traffic while on the road.

A cheaper solution for you... try Live Police, Fire, and EMS Scanners on RadioReference.com