Ultimate radio reception in an e46

Hi guys, I've been thinking about getting an MP3-capable HU to replace the Business CD unit in my 2000 323i. I'm on the road in the boonies a lot, and there are a few radio stations I really like in fringe areas,
especially during football season. If I do this, I'd like to get a unit with maximum radio sensitivity. So my questions:
Who do you think has the best radio reception, primarily on FM? I was thinking a Pioneer with Supertuner IIID, or a Blaupunkt Digiceiver... Those have the best specs, anyway. Anyone have any experience with those?
Would a new unit, even the best ones, really get stations better than the stock Business CD unit? For weeks I've had the horrible noise problem on AM that I've seen described before, but just today I tinkered with the amp in the driver side back c-pillar and it cleared right up. FM was never the worst... So would this be a waste of time? I *think* I could find something better, but I'm not sure. I don't even know what the specs on the Business CD model are, or even who the OEM manufacturer is.
Is there anything else I should consider?
I've got a harebrained idea for possibly trying to somehow put a VW Jetta/Golf antenna in place of the the roof cell antenna and tap into it somehow, but I'll save that one for later. :) Maybe the diversity antenna would work okay with a more sensitive tuner.
Thanks for reading. :)
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The problem with AM reception is usually related to the ground for the antenna. My AM reception in fringe areas goes to pot when I turn on the rear window defroster - some crossover in the ground and amps is the problem. The radio was replaced just before the warranty ran out and it improved things for a few months until the ground went bad again.

My guess is that ANY antenna other than the in-glass one will be better. The ground problem will continue to come back with the diversity antenna and amp.
FloydR
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What you need for good reception is a decent aerial.
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So is the diversity antenna really that inadequate?
I may actually try to substitute an AM/FM antenna for the stubby cell antenna on the roof and see what happens. It's not like the cell antenna has been or ever will be used anyway. :)
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IMO, any time you need an in-line amplifier between the antenna and receiver, it's inadequate. It's also inadequate in that every connection between the antenna and receiver has to be perfect: that's why *REAL* receivers use BNP, Coax or other connectors that aren't as subject to corrosion, broken wires, etc.
Floyd Rogers
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Here's another option if you REALLY like radio. I recently got an XM SKIFI 2 and I'm loving it! 200+ stations to choose from and you can pause, rewind, fast forward. The normal digital features. It will cost around $175 USD for a nice, clean install (did mine myself). The reception is great but if the "line-of-site" is blocked, the reception may fade for a second, but is tons better than any FM radio. It does require a subscription (what doesn't these days!) of around $13 USD/month but the reception is nation wide. At least in the US48.
Hope this helps.
Chris
wrote

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Does anyone here have XM radio? I love it and the reception issue is moot...most of the time! :)
wrote

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Floyd Rogers wrote:

Really... well, I'll need to inform our (overpaid) RF design engineers that there is no longer any need for a receiver preamp in any sensitive RF receiver design architecture. I'm sure that they will be relieved to learn this as those damn preamps are costing a whole lot of money...
The things you can learn on usenet... ;-)
--
-Fred W

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The question is really, where do you put the 1st amplification stage? Putting it near the antenna allows cheaper wires for the long run from the rear window to the head unit. It does, however, open up the SYSTEM to additional failure points..
Get real. Engineering is all trade-offs. In a perfect world, you'd have a full-wave antenna for every frequency you wanted to receive - we don't have that, do we? Nor do we have external full-wave antennas for our cell phones, nor do they have pre-amps between the antenna and receiver.
IMO, the current BMW design is flawed; and there's a lot of pissed customers out there to prove it. If BMW weren't now run by the stylists, and they had real antennas, they wouldn't need the pre-amp. If it weren't for the fact that my DirecTV antenna is more than the recommended 90' from my receiver, I wouldn't need a pre-amp there, and that's about as sensitive as an RF receiver needs to be.
Floyd
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Floyd Rogers wrote:

Actually, it improves the signal to noise ratio regardless of whether you are using cheap wire or not. So in that sense it is a *superior* design. Also, I seriously doubt that adding a preamp is less expensive that the amount they would save by using cheap antenna cable. Where they are able to save money is in the front end of the head unit receiver.
But you are correct in that adding a preamp does add to the complexity and is prone to failure as are all active electronic components.

Gee, thanks again for the lecture. Once again I learn something new... Engineering is all trade-offs. Who'd a thunk?
And here I thought it was in *design* that the trade offs were made...

That is your opinion and you are entitled to it. Yeah, there are pissed off BMW customers, but that does not mean that the design is flawed. Hell, they are pissed off about everything, not just the radios. Does that mean the design for the rest of the car is flawed too?
Do I think the BMW supplied radios are very good? No. But I think the weakness is in the stock POS head units (which is what necessitates them needing a preamp) not in the antenna preamplifier.

No. There are far more demanding RF receive applications out there than DirecTV (or any other entertainment receiver). Preamps are de-rigeur in those applications.
--
-Fred W

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Not that I want to get in the middle of this argument :), but do you think they'd still use an amp if they had a 32" whip antenna instead of the heating element for the back glass? Seems to me like that would be the reason instead of the weak front end in the HU, but what do I know.
BTW, that was a serious question, not a smart-aleck one. :) I don't know the answer.
Anyway.... Based on some posts in other forums, I've about decided on a Pioneer. Does anyone know of a Pioneer with orange or red buttons? All the current models seem to have green ones, which obviously doesn't match the rest of the dash at all.
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RP wrote:

Great question.
BTW - Do you happen to know the difference between a good question and a great one? Well... a great one is one for which I know the answer! ;-)
The "diversity" antenna in the rear window is perfectly capable of pulling in plenty of signal if the receiver is of reasonable sensitivity even without the use of an antenna preamp. I only know this through imperial evidence.
Have an older 3 series with the pre-amp and diversity antenna. Radio sucked the big one. Bad AM, Bad FM, and what are you supposed to do with a cassette deck these days? Bagged the head unit and replaced it with a Sony (not particularly expensive) in-dash CD receiver that had a good FM sensitivity spec. Works like a proverbial champ with no power going to the preamp.
--
-Fred W

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Thanks Fred, that's the kind of real-world experience I was hoping to hear about. One of my concerns is that I do all this and then reception isn't noticably better and I've lost my OEM look. So your case is very encouraging.
Do you have any idea who made your old radio? I think my version of the Business CD is made by Alpine, but I'm not absolutely sure.
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RP wrote:

I think mine was an Alpine too. I know there was a way to find out based on a code that would come up on the came when you pressed the buttons in a certain combination. Sorry I don't have more definite info on that. You know what they say about when you start to get old... The memory is the second thing to go, but I'll be damned if I can remember what the first thing is. ;-)
--
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Malt_Hound > wrote:

One more thing, the car I spoke of was a 1995, so this was pre-Business CD. Also, the Sony head unit I bought was one of the "explode series" that has a dark face plate and reddish graphics so it actually fits in with the orange illumination pretty well.
--
-Fred W

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My car before this one was a 1995 318i, so I probably had that exact same cassette unit. :)
I'd noticed that Sony series, too... It seems hard to find a unit that has orange or red lighting right now, but those do. If I really want a Pioneer that looks okay, I might have to get a discontinued model I saw that has it. But it's good to hear that the Sony's FM specs seem to be realistic.
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RP wrote:

Well, not all of the Sonys have the same receiver because the FM sensitivity specs vary.
Also, I saw where Blaupunkt has brought back the Montreal which a lot of folks have used in BMWs because they are good decks and match the dash well.
--
-Fred W

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I thought I would update this for anyone who might be interested...
The Pioneer I was thinking about was on sale at Circuit City, so I went ahead and had it put in last Friday. After a few days of careful listening, I'm somewhat disappointed. Reception isn't really better, and in some cases is worse. My sense is that raw sensitivity is somewhat better than the Blaupunkt Business CD that was in there, but losing the diversity and having two antennas to "choose" from has hurt performance. At times I'll get stations that I didn't get before, but my target station that is 90 miles or so away comes in even more erratically than before. And a couple of stations about 45 miles away that were very solid are now a more sporadic. I *suspect* this is because I now have a narrower reception range than I had before.
So now I wonder if a whip would help, especially since I've essentially lost half of the antenna I had (with the new radio only utilizing one of the available in-glass antennas)...
Does anyone have any more thoughts on that? Or what I could try next to improve reception?
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RP wrote:

What is the sensitivity of the radio you bought? Did you compare it to other available models? Not all decks are created equal.
But, all other things being equal, a whip antenna will outperform the diversity antenna.
By the way, are you powering the diversity antenna's remote amplifier? You typically use the switched 12V power that would go to an amplifier or power antenna for that.
--
-Fred W

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The Pioneers are at 8db sensitivity, which is the best you can get except for the Blaupunkts, which are listed at 6db. (And that number is so low, I doubt it's real.)
The question of whether the amp was still powered was something I thought of, too. I assume it still would be, as the amp is back in the c-pillar. But I guess it's possible that the other end of the power line to it is up by the radio, and the installer somehow disconnected it.
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