New Install of BC-T15 and BCD996T with Built in GPS

[KI6ABZ]

Originally Posted by davidmc36

Can't stand listening to music in the car. I don't listen to music a lot regardless of where I am. I will have to throw the deck back in and plug in the Sat Rcvr when we go on vacation this year, wife would refuse to go if it was not there, but that only takes 15 mins. or so, unplug one set of connectors and plug in another. Dash has four screws. Very slick car to work on actually.

Just get a power amp or amplified EQ (EBay: less than $40 if you look hard enough) and connect it directly to the Sirius deck by way of a dual-audio taper potentiometer. If you have the chops to hook up a GPS receiver, you can hook up an audio amplifier. This is how I used to run my CD player (and later, MP3 player) before I got a Pioneer stereo with a line-input.

I read a post somewhere a while back where a guy was talking about using two identical scanners tuned to slightly different freqs to get both channels of the stereo FM.

That won't work for more than one reason. First off, the audio is only broadcast on one FM carrier. The stereo information is encoded on a subcarrier inside of the audio signal (it's actually AMing the FM in the 23-53 KHz part of the audio signal.) The separate left and right signals are summed to mono on the main carrier and subtracted on the subcarrier. The receiver adds them together to get the left signal and subtracts them (reverses the phase of the difference signal) to get the right channel.

Essentially, audio that appears only in the mono signal goes to both speakes. If a copy of that audio is in the difference channel, then that audio ends up on the left side. If the audio is copied to the difference channel but in reverse phase, it'll end up only in the right speaker. This lets FM broadcasts work on every FM broadcast receiver ever made, not just modern receivers. This technique is also why FM stereo has a little more static than when you switch your radio to mono; the difference channel is being demodulated from (essentially) an AM signal in the audio stream; any noise that affects the original FM stream is going to be amplified by this second demodulation process.

So there is only one FM signal, not two, and you're not going to get stereo by using 2 radios on slightly different frequencies. If someone thinks he did that, he's fooling himself.

[davidmc36]

Originally Posted by yorkphotog

Did you buy the Uniden shell for both of your scanners? I remember that I bought one for the BCT15 that is mounted in my dash, but for some reason or other I wasn't able to mount it with the shell. As it stands, the BCT15 in the dash is basically unremovable..but it's not a big deal to me since I program the scanners via the front serial port.

I didn't buy anything extra. I didn't like the DIN sleeve that comes with them either. I went for the ISO mount option. I used the ISO brackets from the factory deck for one and had to make a set of brackets for the other. Essentially like you say, non removable but not an issue with the front port. It would acutally only take about an hour to remove both and put the CD player and storage compartment back in. The dash on new cars is so easy to work with compared to pre 90's stuff.

[davidmc36]

Originally Posted by KI6ABZ

Just get a power amp or amplified EQ (EBay: less than $40 if you look hard enough) and connect it directly to the Sirius deck by way of a dual-audio taper potentiometer.

I just may have to look into using one of the amps that I have sitting around. With the variable output of the Sirius Rcvr and the variable input of the amp that I am thinking of, plus a potentiometer setup it should work out good.

Great explanation of the stereo FM. Something I have never taken the time to learn about before. I would like to dig up that post that I read before and figure out what buddy was reffering to.

[RolnCode3]

I would consider putting a rubber grommet on the coax hole. The edges look sharp, and with movement of the vehicle you could cut through the coax.

[davidmc36]

Originally Posted by RolnCode3

I would consider putting a rubber grommet on the coax hole. The edges look sharp, and with movement of the vehicle you could cut through the coax.

Good point. That was an in progress shot and I wrapped a few wraps of electrical tape around the coax and polished up the hole for the final assy.

[N9JIG]

Originally Posted by kirka127

Wow that is cool the way you hooked up the GPS to both scanners.

On my install I have a single GPS receiver hooked to 3 scanners as well as an APRS radio. It works just fine!

http://www.radioreference.com/forums...t-install.html

Pilot Radio

[davidmc36]

So here is another update/question. Today was the first hot sunny day here since setting this up. I seemed to have toruble keeping a GPS lock. I think it was temperature related. If I cranked the AC and put a piece of paper over the antenna to direct cool air over the antenna the signal stayed locked on. Is that my imagination or is the cheapo antenna I got from Ebay breaking down in the heat? Why do they make those things black other than for asthetics if you put it on the top of your car? I'm not sure what to do. Get a better antenna, cover the one I have with something white that would keep the temp down without sheilding the RF, put it on top of the car so it gets airflow, duct the AC across it, or what. The antenna has tons of coax length to put it anywhere I want. I coiled the extra in a kind of figure eight under that dash. I wonder how much effect that would have on quality of signal? I know you can do things like make a balun by coiling coax but I don't know if there would be any applicable affect here.

Any sage advice with this?

[RolnCode3]

Originally Posted by davidmc36

Good point. That was an in progress shot and I wrapped a few wraps of electrical tape around the coax and polished up the hole for the final assy.

Cool. Nice job, looks like a cool hack.

[davidmc36]

Originally Posted by KI6ABZ

Just get a power amp or amplified EQ.

So I got to thinking and digging through some boxes and dug up this oldie. Had to pop the cover off to confirm the pinouts, though most of them follow the grey/green etc. common to a lot of automobile stuff. And I'm drinking a Diet Pepsi as I work and hear a voice in my head; "I see you are drinking a Diet Pepsi. Is there anything else from your youth that you would like to experience?" And I say; "Sure, how about some of those coooooooool LED audio level meters on my stereo."

So it seems to work OK. I twisted up a connector to a couple scanners in the house to check the fader etc. I think this will do the trick quite nicely for running the Sat Radio. Slip a potentiometer in the mix and voila! Coooooooooool LED's Not real huge either so it should hide away somewhere fairly easy. Just need to make a mount.

[davidmc36]

Originally Posted by davidmc36

So here is another update/question. Today was the first hot sunny day here since setting this up. I seemed to have toruble keeping a GPS lock. I think it was temperature related. If I cranked the AC and put a piece of paper over the antenna to direct cool air over the antenna the signal stayed locked on. Is that my imagination or is the cheapo antenna I got from Ebay breaking down in the heat? Why do they make those things black other than for asthetics if you put it on the top of your car? I'm not sure what to do. Get a better antenna, cover the one I have with something white that would keep the temp down without sheilding the RF, put it on top of the car so it gets airflow, duct the AC across it, or what. The antenna has tons of coax length to put it anywhere I want. I coiled the extra in a kind of figure eight under that dash. I wonder how much effect that would have on quality of signal? I know you can do things like make a balun by coiling coax but I don't know if there would be any applicable affect here.

Any sage advice with this?

Well I think the GPS signal issue is cured. I tried it this morning while it was still cool out and was still having trouble locking on.

So I tried a little experiment with a piece of tin foil. It went from zero signal on zero sattelites to a lock in about 10 seconds. So I went to the effort to put it on the rear roof where the Sat Radio antenna is. Getting pretty much full bars from 11/11 satellites now. The doo-dad that I made to hold down the coax on the roof is a bit cheesy so I need to get a piece of some nice black plastic and make a nice rounded retainer with a channel in it for the coax, something like what comes with the Sat Radio antenna.

I never had any issues before with handheld GPS or my Bluetooth reciever sitting on the dash so I think the Ebay antenna is a touch on the cheap side. Not a huge issue to overcome since the routing of the coax to the back is super easy on the both my Hyundai's.

More pics to follow when I get the sat radio amp set up, prolly later nex week.

[davidmc36]

Got the Amp installed. Attach brackets are a bit cheesy but will do until I find some black or grey plastic to make them from. But it works awsome!!! Just tested it with a scanner as input since the Sat rcvr is in the wifes car. Volume knob is beside the cup holder.

[KI6ABZ]

Nice!

If you add an A/B switch and a mini-phone jack next to the volume knob, you could use it with an MP3 player, too. At one point, I had an XM receiver, HD receiver, and iPod patched in to my Pioneer. I used a pair of DPDT switches in the dash to switch between them.

[Renegade631]

That looks like it was a lot of fun to install, not to mention the hours of enjoyment in the future.

Nice setup man!

[davidmc36]

Originally Posted by KI6ABZ

Nice!

If you add an A/B switch and a mini-phone jack next to the volume knob, you could use it with an MP3 player, too. At one point, I had an XM receiver, HD receiver, and iPod patched in to my Pioneer. I used a pair of DPDT switches in the dash to switch between them.

The switch is an excellent idea, along with putting the jack beside the volume. I did hook up the volume with an in-line jack so the amp can be used for MP3 or something else like you say but did not think of a permanent, switchable input. WATCH FOR UPDATES!

[Smerri]

That is quite the set up. Really great job!

[tekshogun]

Nice setup all around. Great to see people doing serious electronics work and not being scared of it. I found it quite interesting that you removed your radio for this setup, but you like what you like. Keep it up.

[DaveNF2G]

You should probably put a grommet in that coax hole on the back of the scanner. A few months of vibration and rubbing and you could start having some mysterious system problems.

[EDIT] The second page of messages in the thread did not show up until after I posted. I see someone else has already picked up on the coax issue.