Weak FM radio reception in 2010 Prius?

OK thats what I thought. Unfortunately all that poves is that there is metal in the antenna rod..... The problem is further downstream than that.

NO, this is what I am tying to point out. The coax that brings the RF to the Antenna Pre amp could be bad, bad crimps on the connectors, the preamp could be bad, or the coax from the Preamp could be bad. The Preamp itself coud be putting out TOO much signal, thus overloading the front end of the receiver. This will give EXACTLY the same results as NOT enough signal!
It coud be even as simple as the antenna cable is not plugged firmly into the antenna jack on the radio itself!!!

Yes I will agree with you there, the problem is before the switching system. AND before the OUTPUT of the AM/FM portion of the unit.

At the point the FM output gets to the switching point where it switches between FM, CD etc, it is at "Line level".. like you thought, the problem is upsteam of this. Either the FM receiver portion of the package is crap, or the antenna system is crap. This is where the output of the antenna system needs to be checked to figure how much level is actually getting to the receiver. This is why I brought up the idea of plugging a completely DIFFERENT antenna into the radio to figure out if the Antenna System is the problem, or is it the FM Receiver thats bad..
This problem seems to be in some Prii and not others. Like I mentioned in an earlier post, my coworkers V/AT works just fine. If anyone would notice a problem like this, he would.
Sounds like a batch of BAD somethings got thrown into the assembly line!!!

 

Not to further generalize the problem - but it is clearly shown in different radios (stock, JBL/nav, aftermarkets), and changing the antenna does not seems to help.

That leaves everything in between - coax, amp, routing path.

It's darn near impossible to get at the places in between, so we are stuck and at the mercy of Toyota.

 

This is why I am saying again - write to Toyota about it!

 

I too am experiencing weak FM reception in my Prius, purchased in late July. I will also write to Toyota to complain.

 

Would anyone consider hooking up a different type antenna at the back of the radio to check? I don't want to take my dash apart until I get my new head unit.
I was thinking like those tape type you stick along the outside edge of your windshield. I did that for one of my cars long ago and it really helped.
I think many, many people still use FM across the country and worldwide so this really is a substantial issue.

 

This test wil only be VALID for those folk with the problem. My Gen II works fine, My pal's V/AT works fine, one of you that has the problem and are slightly technicaly inclined, go to PepBoys, Kragen etc. and BUY a whip antenna. They usually come with 10 ft of coax, a premade Motorola plug, just pull out existing cable out, plug the new one in!!! If you are going to do the test you have to use a REAL antenna, and not some Radio Shack type of crap!

Just plug it into the back of the radio and see what happens. If the system now works fine, the cars antenna system is crap. If you get the same signal results as the stock antenna, the radio is crap.
Until this test is performed we are NO closer to resoving the problem. At some point you have to define the problem to a repeatable demonstration so the dealer has a specific item to repair.

If some one in the LA area wants to try this test, I will offer my assistance to help you . PM me!

 

I just changed my radio and before I did my reception was bad and now it is great with the new JVC I installed.

 

This is the radio I installed http://priuschat.com/forums/gen-iii-2010-prius-audio-electronics/72065-just-installed-new-dvd-nav-unit.html#post1001389

 

OK there you go people... while this is the more EXPENSIVE way to run the test I suggested, it CLEARLY tells me that the Antenna system is OK.
It certainly points to the receiver being the PROBLEM.

Now all you have to do is convince the Dealer to swap out your receiver with a new one. I would program all the worst reception stations you can find into the radio, now matter what preset the dealer tech picks, the problem will be very obvious.

NEW RADIO..hopefully with a better receiver!!!

Of course how many radios are you going to have to go through until you find one that works properly!!!

 

Add me to the list of people with crappy reception. On my other and previous car I could pick up local stations with no static...I get static quite often now. I live right in the middle of LA and can see the radio towers from my house...another sub-par aspect of my Prius. :-/

 

I'm wondering if anybody has replaced their receiver just to find the problem is still there?

No matter how good the receiver is, if the antenna is not installed right its still a no go.

I'm almost suspecting a problem with the coax crimping technique or tool used since its so common.. maybe a crimp too deep or sloppy in which either case there is a short from ground to lead on the coax making the antennae basically invisible.

Another poss problem is if the coax used did not come in a kit where its pre-cut to a certain length that could be an issue.
The coax needs to be cut to a harmonic of the frequency used. Random lengths could cause random results.

Seals being bad allowing water to get inside and "stay" where the antennae connects to the coax on the roof could cause a high resistance short too.

Then of course we have loose connections on the back of the head unit or even jammed extreme kinks in the coax causing breaks or shorts.

Just a thought.... or maybe a few.

That should be easy to troubleshoot with an ohm meter once you have access to the coax when you disconnect it from the head unit.

I"m guessing that antennae is a 50ohm setup but could be wrong.
If that's right, there should be 50ohms between ground on the shell of the coax and the center conductor when the other end is hooked to the antennae.. if its disconnected from the antennae, it should be zero, or there is a dead short somewhere in the line.

These are all things the mechanic at the dealership should check out.. but knowing the way they work.. they no longer know how to do the simple things.

If it doesn't show up on a computer screen somewhere that tells them the problem, they just start replacing things until its fixed.

That way, they make more money and has less labor time to be free to do the same thing on another job.... at the end of the day, they make more money than doing honest troubleshooting.

Thats the reason they have to literally get permission from Toyota to do certain things so as to not rack up the bill at Toyota's expense.

Of course if you don't have insurance or warranty.. they have no problem passing the cost to you!

But then of course.. maybe its the head unit and lets just replace that first!....... How much do those cost again?

 

Carefully READ Post 67, AND 69......

Any Questions.....????

 

Missed that... thats encouraging... sure makes me wonder what the problem part is and whether its something that will go bad soon in those units that do ok right now.

If your in an area with decent signal, its really hard to determine if you've even got a problem.

 

I would say yes to that. When I get into the downtown area, most of my stations come in good, no static. Leave the general area and the reception becomes unbearable. Turn off the radio and the CD comes on.

 

ad Windstring long post:
1. The coax cable can be of any leght - no harmonic freq or so. Longer cable will have just a bigger attenuation and you will get the lower signal level at the aerial radio input.
2. 50 Ohm is not a resistance, but impedance (a/c resistance) - ohm meter will show you the indefinite resistance in case the cable is not shorted, because DC voltage.
3. Toyota installs car radios for tens years, they know how to crimp cables, I'm sure. They simple choosed a crapy model of receiver for 2010. They have to find the reason and fix it. But the unit is working, only has a low sensitivity or other important parameters are out of borders. If the radio doesn't work at all, it will be easy - warranty process and 3rd party Toyota supplier responsibility. There is no exact specification for the receiver in the car - hard to compain exactly. BTW. there was an issue with XM receiver - TSB said replace it.

 

YES

Now here is a lad who "Gets" the idea!!!

 

Keep in mind, the issue has been reported on both stock, and "JBL Eclipse" units - both made by differing companies.

I'm running the stock radio right now, and last week went to the beach (Laguna) - could not use the radio *at all* - even most AM stations were staticy

 

These may be different types of antennas that have self contained grounds, but many need the coax to act as the ground portion to match the radiating portion which is the antenna itself.

Dealing with radios that only receive, its harder to see the problems with mismatched antennas, but when they transmit too, the problem becomes more obvious as any mismatch causes reflections for power back to the final transmitters in the form of standing waves.... this ratio not only determines how fast those final transmitters heat up, but proportionately power that's reflected back is not transmitted and so wasted as dangerous heat that can toast the final transmitters.

Nevertheless.. antennas that are tuned bad for transmit, correspondingly have bad receive.

You dont notice it much unless your in a fringe area and then you really need to suck up every bit of signal you can.. then it can make all the difference.

It sounds like this is not an antennea problem anyway and I cant imagine the cables not being precut at the factory if it does make a difference.. , the factory never knows what rig they are going in and may depend upon the tech to cut the proper coax length to reach the head unit.

I used to rig up high powered mobile installations with linear amplifiers and coax length made all the difference in the world as to whether the power would all go out the antennae or some would get reflected back to toast the radio or at best give it a short life.

Those antennas that were tuned to transmit the best, also received the best.

It sounds like its going to be hard to tell if you have a bad setup unless you now cant get stations that you used to could.

 

There's a new thread on someone else who installed the high-end Kenwood 2DIN. He states that the reception is just as bad with his new HU. All this really does is show yet again that the issue is not with the stock radio. He also sees a slight degradation with his sharkfin - compared with stock antenna.

All these things point a something between the antenna and the radio - not the radio itself, and not (I believe) the antenna itself.

http://priuschat.com/forums/gen-iii...ius-ii-new-double-din-stereo-new-17-rims.html Post #9

 

He also stated that he doesn't listen to FM/AM normally so perhaps his comparison isn't reliable. In any case, we really need someone to perform a more accurate comparison before we will really know for sure.
I was thinking the Pioneer 4100DVD... any feedback on that unit?