Radio Signal Strength

[94_302]

What is the average signal strength for a properly functioning head unit? I just tested mine and on scan with FM stations it was mid 40's at best but ranged from 20's to 40's. A few AM stations hit 50's. Where is the ground for the antenna located? Or if the strength is this low and has that much static is it a lost cause and I just need a new head unit?

[Breadfan]

What do you mean by mid 20's 30's and 40s?

[94_302]

Press 3 + 6 on the factory head unit then press 3 and it will give you the signal strength. I just tried playing with some wires and it was right at mid to low 30's and had a ton of static.

[Bobmiddle]

My FM went out almost a year ago. Took it to the dealer and they said it was because of the tint( BS ). There are a couple other threads about it on here but no real answer on why. I thought about just gettin an aftermarket antenna that will run on the inside of the car(like the ones people use when they shave there oem antennas) But I have not done it yet.

[magindat]

I think this has been gone over in the past to the conclusion that the FM 'goes out' in the factory radios.

I have replaced radios with upgrades that had little to no FM reception. Used the factory glass antenna wire with no mods and have terrific FM.

Unless there is something else specifically wrong, I'd aim at replacing the HU.

[94_302]

As I suspect I guess I'll be looking for a new head unit. Are they typical plug and play with the OEM connectors? I'll also need a special unit to keep the steering wheel and 6 disc changer right?

[Blackmobile]

Don't feel alone, my FM signal is crapping out too, and I know others who have gone through this to.

[magindat]

As I suspect I guess I'll be looking for a new head unit. Are they typical plug and play with the OEM connectors? I'll also need a special unit to keep the steering wheel and 6 disc changer right?

If you go aftermarket, the changer no worky.

There are a number of SWI's depending on model/brand radio you buy.

Stock sub won't work either.

Let the fun begin!

[magindat]

I see you are Tally/Miami. Plan a layover in Vero and we'll get it done. Buy your stuff from John Kuhn.

[94_302]

I can deal with the stock cd changer not working, but the sub even though it's puny it's better than nothing I guess. I use my ipod through the cassette adapter everywhere. It's when other people drive it that they use the radio so I may just say oh well and let it be. I'm not ready replace everything at once.

Would another stock head unit be the way to go or is it a design defect and they are all just counting down till they stop working.

[magindat]

Would another stock head unit be the way to go or is it a design defect and they are all just counting down till they stop working.Some do and some don't. Seems to be pot luck.

[Bobmiddle]

There are a couple stock stereo's for sale on this board $150 for a used oem is not bad. I am waiting to replace with double din dvd nav unit.

[94_302]

Some do and some don't. Seems to be pot luck.


Hmmm then I guess I'll just wait till I'm ready to do everything at once.

[racorcey]

Press 3 + 6 on the factory head unit then press 3 and it will give you the signal strength. I just tried playing with some wires and it was right at mid to low 30's and had a ton of static.

Hey, I didn't know that these radios had any diagnostics built in! I went out and tried it, and you were certainly right on the money. Just so you know, most of the stations I tried were in the mid 40's to near 60. I assume this means the reading is in microvolts, since it usually takes at least 40 microvolts of receive energy to produce a useable FM stereo signal. For a mono signal, you can get away with about 20 microvolts. By means of comparison, a communications grade receiver (such as for emergency, etc.) has sensitivities down to .1 microvolt for a useable signal - but that's for narrowband FM. Our standard broadcast FM is known as wideband FM.

I did push some other numbered buttons to see what they would do, and they definately have some functionality. By any chance, would you have a list of diagnostic functions, or a reference guide, website, that has more on this, would you?

Thanks!

- Randy

[racorcey]

What is the average signal strength for a properly functioning head unit? I just tested mine and on scan with FM stations it was mid 40's at best but ranged from 20's to 40's. A few AM stations hit 50's. Where is the ground for the antenna located? Or if the strength is this low and has that much static is it a lost cause and I just need a new head unit?

Are you sure you aren't having a problem with the antenna amplifier, located, I believe, on the rear shelf package? I have seen references to this in past on CVN, although nothing recently.

If this amp quits working, or is only partially working, it will not give the necessary signal strength to the radio for good operation. The rear window antenna is bad enough to begin with....the antenna amplifier is next weak link in the chain.

[94_302]

http://www.mercurymarauder.net/forums/showthread.php?t=22146&highlight=radio+test

Do you have any pics of the antennas location or the amp as well as how to test it?

[racorcey]

http://www.mercurymarauder.net/forums/showthread.php?t=22146&highlight=radio+test

Do you have any pics of the antennas location or the amp as well as how to test it?

Thank you for the link. It gives me just enough to wet my appetite.

Not to sound flip, but I hope you have a service manual. The whole description, which is rather lengthy, can be found in section 415-02.

For 03-04, they have seperated out the FM and AM antennas. That is, the AM antenna is part of the Rear Defroster grid array, and the FM antenna is a single wire running just above the main Rear Def grid, very near the top of the rear window.

There is another device, called the "antenna isolator module." It is mounted under the rear shelf package tray trim panel. It is used to separate the AM signals, FM signals, and rear defroster power. This description from Ford is somewhat of a misnomer. While it does keep rear defroster power from appearing on the signal lead-in cable going to the radio, it really combines the AM and FM antenna signals into one that can be fed to the radio onto one coax cable. It also acts to amplify the two bands as well.

I don't know how to tell you test the unit, OTHER than to borrow an old, standard, external car antenna and hook it up to your radio in place of the car's regular antenna connection. If the signal dramatically improves, it could be anything from a broken rear window grid, a broken wire leading down to the isolator module, or even a break or bad connection coax wire - the one from the isolator module to the radio. And finally, the isolator module (nee amplifier) can also be bad.

You know how to use the signal strength meter test function of radio. I say hang an old style antenna to it and see if things improve. That might just eliminate the potential for a bad radio head. Of course, if nothing improves, then subbing another radio sounds like it might be the fix.

Talking to some of the Ford/Merc techies that I know (mostly module jockies), their experience has generally seen the rear window grid to be damaged more than a bad radio. They have also replaced a few isolator modules as well.

I hope this helps you.....

- Randy