Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: aux in to the car's audio? FM, aerial cable?  (Read 3198 times)
NEVBEN
Member

Posts: 43




Ignore
« on: March 15, 2012, 03:09:58 PM »

The downfiring built-in speaker in my mobile leaves a little to be desired, especially with the head unit mounted under the seat.  Rather than mounting a remote, I want to pipe the audio into the car's system.  Unfortunately, the head unit is fresh out of inputs since it has a built-in tape deck and aux-in is occupied by the disc changer.

I could rip out the disc changer and patch in, but it's kind of quaint and I actually still have a few CD's.

Instead I thought I'd either try a mini FM transmitter, or one of those deals that patches into the cable to the aerial at the back of the head unit.

I've heard the FM units in person working fine for personal audio devices and so on, but I've read accounts of them being noisy and flakey.

The accounts I've read report the aerial cable patches work better.

I know I don't want a tape-deck adapter because I don't want the cable hanging out the front of the deck.

I want to inquire what other's have had good results with.
Logged
NEVBEN
Member

Posts: 43




Ignore
« Reply #1 on: March 15, 2012, 03:38:39 PM »

I should clarify that when I heard the mini FM transmitter working well, it was like 18 years ago.  I heard the FCC regulated the power down on them and maybe that's why people get some poor results.  I don't know.
http://www.amazon.com/Monster-RadioPlay-Transmitter-MBL-FM-XMTR300/dp/B000E43GOO/ref=sr_1_10?m=ATVPDKIKX0DER&s=electronics&ie=UTF8&qid=1331851301&sr=1-10

The other option is a direct FM modulator.  They work on some frequency like 87.9, but instead of transmitting RF, they modulate right on an antenna cable patch.  Here's what I'm talking about for an example, not wanting to spam: http://www.amazon.com/Audiovox-FM100A-Modulator-Isolation-Transformer/dp/B0001KO7UI/ref=sr_1_4?m=ATVPDKIKX0DER&s=electronics&ie=UTF8&qid=1331851301&sr=1-4
« Last Edit: March 15, 2012, 03:50:08 PM by NEVBEN » Logged
KG4NEL
Member

Posts: 373




Ignore
« Reply #2 on: March 15, 2012, 04:01:15 PM »

How about a Y-cable on the aux-in?
Logged
NEVBEN
Member

Posts: 43




Ignore
« Reply #3 on: March 15, 2012, 04:31:34 PM »

It's a little tricky because it's not a proper aux-in, but a factory-engineered cd-changer to head unit interface cable.  There's signaling and control functions over a multi-pin interface and I'm concerned that if the head unit doesn't get a proper response from the changer, it will error out.  No doubt it could be tricked but it might not be the simplest way.

What I can think of is breaking out the audio signal cables from the changer and patching the VHF radio's output into those circuits (stereo) with resistors on each input, but then I might have to be listening to a CD to hear the VHF radio in the mix.

Come to think of it, I might try to patch the VHF radio into the circuit from the head unit to the amplifier.  I like that because then I can get a mix.  The only tricky thing is to stage the gain right.  Maybe instead of resistors, I'll use some potentiometers on the little mixer.
« Last Edit: March 15, 2012, 04:33:54 PM by NEVBEN » Logged
KCJ9091
Member

Posts: 0




Ignore
« Reply #4 on: March 16, 2012, 06:52:05 AM »

The FM transmitters work fine IF, and it is a big IF, you can find a clear channel to tune it to.

The other issue with using the car audio system is you can only listen to one at a time, no listening to the am for traffic reports on the commute and joining the ragchew on the repeater at the same time.
Logged
AA4PB
Member

Posts: 12638




Ignore
« Reply #5 on: March 16, 2012, 08:16:53 AM »

Its a lot simpler to just mount a small external speaker for the transceiver.
Logged
NEVBEN
Member

Posts: 43




Ignore
« Reply #6 on: March 16, 2012, 10:54:35 AM »

I live a hundred miles from traffic, but I do like to have both music and chatter at the same time mostly because I can have 30 minutes without 2m activity.  I like for 2m to break through any music if I so choose, which is why I thought of mixing it before the amp.  But retro-fitting the stock system with this is too complicated for the benefit.  Frankly I don't even want to wire a modulator.  I might have worked the mixer into a completely new system if I was willing to spend all that, but I'm not.  So I'm thinking I will either try the FM transmitter (no mix), or an external speaker.  I looked at using a quality 60W amp and car audio speaker, but the cost is a little too high.  I guess I'll browse through the eham reviews of external speakers.
Logged
KJ4OBR
Member

Posts: 103




Ignore
« Reply #7 on: March 16, 2012, 11:45:46 AM »

I tried the fm micro transmitter and was left seriously unimpressed. Spend $8 on a jetstream external speaker and shove it under the dash it's more than loud enough for most modern cars and enjoy. If you drive a diesel get an amplified Motorola from e- whereever.com for a few bucks more. Using the built in sound system is a good idea in theory, in practice no one I know who have tried it liked it enough to keep using it.

73
Dave


I live a hundred miles from traffic, but I do like to have both music and chatter at the same time mostly because I can have 30 minutes without 2m activity.  I like for 2m to break through any music if I so choose, which is why I thought of mixing it before the amp.  But retro-fitting the stock system with this is too complicated for the benefit.  Frankly I don't even want to wire a modulator.  I might have worked the mixer into a completely new system if I was willing to spend all that, but I'm not.  So I'm thinking I will either try the FM transmitter (no mix), or an external speaker.  I looked at using a quality 60W amp and car audio speaker, but the cost is a little too high.  I guess I'll browse through the eham reviews of external speakers.
Logged
KQ6Q
Member

Posts: 961




Ignore
« Reply #8 on: March 19, 2012, 01:45:14 PM »

If your vehicle has a height-adjustable headrest, with two chrome rods visible when it's raised, put a little extension speaker between the headrest rods, shooting right at the back of your head. Works very nicely. The little extensino from MFJ is inexpensive, and you cut the little mounting bracket in half with tin-snips, and use it to wrap each end around the chrome rods. MUCH better than a speaker muffled under the seat.
Logged
K0BG
Member

Posts: 9830


WWW

Ignore
« Reply #9 on: March 19, 2012, 03:26:38 PM »

Actually, muffling under the seat is a rather good idea when operating SSB. It helps cutoff the high frequency component we all have to deal with.

I know lots of people mount speakers on the headrest bars, but personally I think it is a bad idea. That is, besides the safety issues involved.
Logged

N0MKC
Member

Posts: 68




Ignore
« Reply #10 on: March 20, 2012, 11:05:59 AM »

Unfortunately, the head unit is fresh out of inputs since it has a built-in tape deck and aux-in is occupied by the disc changer.

Get one of the dummy cassettes with a cable that plugs into an MP3 player, ipod, etc. to output via the tape deck and use that; worst case, you'll need to make an adapter for mate the 1/8" stereo plug to whatever your radio uses for a "external speaker" jack.  Simple interface, easy to implement; I use one routinely.

Should be less that $15 at a truckstop; Radio Shack may have them also.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!