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AM Radio Reception
- Thread starter Pantera Dude
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- Roadster
wiztecy
Active Member
Thanks vfx. I don't like that new antenna location at all. Its not a clean look and not the place to put it on a $100k+ car, it really bugs me. I'm going to find some other alternative for it and as a last resort toss it back under the dash. I really was looking for just the booster not to have the antenna moved to a funky location. It looks like a black band-aid running up the window column.
wiztecy
Active Member
I did a quick experiment and pulled the column mounted antenna down and threw it down flat across the dash and my radio station immediately came in with some static. So the relocation does appear to help. I'm going to look at the ribbon antenna that's ran up the column and see if the entire ribbon is used as for reception or just the 2mm circle tube the runs up it. If its just the circle tube, I can cut the fat ribbon off, it then appears the column has enough space between it and the window where I can stuff the modified antenna out of sight. I'll be happy then since it will be out of my sight.
TonyWilliams
Active Member
The Rav4 EV has a lot of AM radio noise. When the motor is coasting (neither producing power, nor regen), the AM radio becomes very clear. Otherwise, it follows a pattern of noise that matches the power used/produced.
When I first got my Roadster some 17 months ago, the radio reception issue drove me crazy. I represent radio broadcasters in my day job and therefore I have more than a passing interest in optimum automobile radio reception. Also, I was moving from owning a BMW in which the radio reception was superb. The radio reception on my Roadster was marginal on FM, and unlistenable on AM.
I tried all sorts of things with the antenna including a temporary mounting of a Wilson fiberglass AM/FM stick antenna, and the installaaion of shielding over the PEM. I concluded after much experimentation that the TESLA antenna running up the side of the windshield with the connected booster yielded just as much AM reception quality as the Wilson fiberglass stick antenna, or anything else I tried (I tried a variety of antennas).
The issue with AM radio reception in the Roadster is the same issue that caused Porsche to ditch the AM radio in its new 918 Spyder. It is the lack of a ground plane for the antenna due to the the car being made of carbon fiber and aluminum. Vehicle owners have been blessed with good AM radio reception since the dawn of radio broadcasting largely because of the great ground plane created by the steel in a normal car. An AM antenna has two parts -- the part the stick up in the air, and the ground. In the TESLA Roadster, and the Porsche 918 Spyder, there is no ground plane and thus very lousy AM radio reception.
Now, add a lack of shielding around the electronic components in the car, and the inherent noise that is generated by a large electric motor, to this lack of a ground plane, and this only further diminishes the AM listening experience. I might add in TESLA's defense, however, that while 20 years ago superb radio reception in most cars was a design and manufacturing imperative, auto manufacturers have moved away from making radio reception a priority as vehicle owners have cared less and less about the quality of radio reception.
Many high-end cars used to and still do have diversity antennas for FM reception which are two FM antennas that electronically switch back and forth to get the best signal and no multipath. Today, it is impossible to find an after-market receiver that accommodates diversity antennas. For AM reception, the stick antenna up in the air with the car as a ground plane gave the best reception although many auto manufacturers found ways to tune their antennas in rear windows to deliver high quality AM reception.
The radio in the Model S seems to work a lot better when I took a drive in it last month. I noticed no noise in the AM section and i suppose the antenna has a ground plane due to the steel in the car. The FM section with HD radio in the Model S is one of the better implementations of the HD radio technology from a consumer use standpoint (i.e. ease of use) that I have seen.
The replacement of the Alpine double-DIN receiver in my later model Roadster with another unit does appear to somewhat improve the radio reception, particularly on FM. I chose the Kenwood DNX-6990HD which I am reasonably happy with (I posted my experience with this swap of radios in another thread). AM reception on the Kenwood for whatever reason is also marginally better, but it is certainly not to the extent that AM is enjoyable to listen to.
In conclusion, due to the carbon fiber and aluminum construction of the Roadster, and the apparent lack of noise filters and chokes at the noise sources in the car, it does not appear that there is much that can be done to improve Roadster AM reception to any appreciable degree.
I tried all sorts of things with the antenna including a temporary mounting of a Wilson fiberglass AM/FM stick antenna, and the installaaion of shielding over the PEM. I concluded after much experimentation that the TESLA antenna running up the side of the windshield with the connected booster yielded just as much AM reception quality as the Wilson fiberglass stick antenna, or anything else I tried (I tried a variety of antennas).
The issue with AM radio reception in the Roadster is the same issue that caused Porsche to ditch the AM radio in its new 918 Spyder. It is the lack of a ground plane for the antenna due to the the car being made of carbon fiber and aluminum. Vehicle owners have been blessed with good AM radio reception since the dawn of radio broadcasting largely because of the great ground plane created by the steel in a normal car. An AM antenna has two parts -- the part the stick up in the air, and the ground. In the TESLA Roadster, and the Porsche 918 Spyder, there is no ground plane and thus very lousy AM radio reception.
Now, add a lack of shielding around the electronic components in the car, and the inherent noise that is generated by a large electric motor, to this lack of a ground plane, and this only further diminishes the AM listening experience. I might add in TESLA's defense, however, that while 20 years ago superb radio reception in most cars was a design and manufacturing imperative, auto manufacturers have moved away from making radio reception a priority as vehicle owners have cared less and less about the quality of radio reception.
Many high-end cars used to and still do have diversity antennas for FM reception which are two FM antennas that electronically switch back and forth to get the best signal and no multipath. Today, it is impossible to find an after-market receiver that accommodates diversity antennas. For AM reception, the stick antenna up in the air with the car as a ground plane gave the best reception although many auto manufacturers found ways to tune their antennas in rear windows to deliver high quality AM reception.
The radio in the Model S seems to work a lot better when I took a drive in it last month. I noticed no noise in the AM section and i suppose the antenna has a ground plane due to the steel in the car. The FM section with HD radio in the Model S is one of the better implementations of the HD radio technology from a consumer use standpoint (i.e. ease of use) that I have seen.
The replacement of the Alpine double-DIN receiver in my later model Roadster with another unit does appear to somewhat improve the radio reception, particularly on FM. I chose the Kenwood DNX-6990HD which I am reasonably happy with (I posted my experience with this swap of radios in another thread). AM reception on the Kenwood for whatever reason is also marginally better, but it is certainly not to the extent that AM is enjoyable to listen to.
In conclusion, due to the carbon fiber and aluminum construction of the Roadster, and the apparent lack of noise filters and chokes at the noise sources in the car, it does not appear that there is much that can be done to improve Roadster AM reception to any appreciable degree.
Thank you for the xlnt writeup John. I guess maybe it's time to start listening to something other than AM.
Art
Art
My main interest in all of my experimenttion with the OEM Alpine Roadster radio was the FM reception rather than the AM reception as I am not generally an AM listener although do enjoy it occasionally. So I did not delve as deeply into trying to improve the AM reception as I could have.
If I was to take trying to improve the AM reception in the Roadster a step further, I would try experimenting by leaving the radio antenna as-is, and trying to create a ground plane in the car. I guess I would start by, as a test, finding two sheets of thin steel that, as an experiment and not for permanent installation, fit under the front and rear hatches and use jumper cables to try grounding them to the electrical ground in the car (like the radio chassis or some other ground), and see if that significantly improves the AM radio reception. If it does, then I would permanently install some sort of copper foil on the underside of the front and rear hatches, and anywhere else I could find to put it where it is not visible, and tie it all together with grounding straps. 3M makes a lot of specialty products for such applications - see, for instance: http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UF6EVsSyXTtnxTynXfEEVtQEVs6EVs6EVs6E666666--&fn=EMI_EMCSolBroch_DMR_6004536.pdf. Digi-Key is a good place to buy such adhesive copper foil in wide sheets: http://www.digikey.com/product-highlights/us/en/3m-emc-products/716.
Another step to take would be to try to install chokes and filters at the noise sources on the car. This is now getting far out of my league but you might try calling around to radio install shops until you find one that has someone there who has been around for a long time and knows a lot about AM noise supression in automobiles. Since you are in the LA area, I suspect there are more than a several good local engineers who work for the AM stations who might also give some advice. Or you might find a radio ham operator who has wresteled with the automobile noise issue. Basically, you are likely looking at acquiring a bunch of noise chokes (like those walnut size things that are often put on power and computer cables but for this application might be larger) and clamping them over the cables running to the Roadster motor, the cooling fan motors and to and from the PEM. It will be a lot of work but if you come up with something that works to eliminate the whine and electrical noise from the Roadster motors and electronics, please share it!
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Also, depending upon the resources that you want to put into this, you might want to consider hiring as a consultant Grady Moates out of Boston who has great knowledge of AM reception issues: http://www.loudandclean.com/. He can be reached at: [email protected] I have known Grady long enough to know that if he agrees to assist you, he will look at this as a challenge and given the right resources, he will figure out a way to get good and clean AM reception in the Roadster for you. My concern about having an automobile radio shop tech go at it would be that they would not have a clue what to do about the different design characteristics of the TESLA. Grady will appreciate the uniqueness of the car and the issues presented.
Not to beat this subject to death, but I shared with Grady my posts and observations above (see above for who Grady is) and this is what he said:
The problem is actually pretty simple, probably stemming from
having unshielded wiring and unfiltered goze-intas and comes-outas
where the wiring enters and leaves the various components in the
engine/controller system. (Like my high-tech terminology?)
Amateur radio operators have become very, very good at reducing
this kind of noise problem, because their hobby (when taken mobile),
is particularly vulnerable to this kind of EMI (electro-magnetic
interference). If you know any old ham radio enthusiasts, or can
get on a blog or list-serve with a bunch of them, I'd bet you can
get some help pretty fast, and the hams would love to get under
the hood of your wheels.
There are reasons why the automobile manufacturer didn't shield,
ground and filter the car well. . . it reduces performance and adds
production costs! The additional filtering and shielding add weight
to the car, and the actual filtering components have an effect on
acceleration. There are two ways of filtering to reduce this kind
of noise, shunt (capacitance) and series (inductance). Either one
alone is only partially effective, one needs to employ both methods
to fully remediate such a problem. Each of these methods can possibly
have a detrimental effect on performance, since the shunt capacitors
slow down the rise- and fall-times of the A. C. waveforms in the
system, and adding series inductances reduces the available energy
to the motor through the insertion of resistance in the wiring,
which reduces the power that can be delivered to the motor during
acceleration. Certainly anything that is done to remediate the
noise problem will have an effect on performance, and the primary
goal of anyone attempting to improve your AM radio reception should
be to minimize this hit on performance.
Anyway, that's Grady's take on the electrical noise in the AM radio from the Roadsters's electronics. Now I will go away and leave this subject alone. :smile:
The problem is actually pretty simple, probably stemming from
having unshielded wiring and unfiltered goze-intas and comes-outas
where the wiring enters and leaves the various components in the
engine/controller system. (Like my high-tech terminology?)
Amateur radio operators have become very, very good at reducing
this kind of noise problem, because their hobby (when taken mobile),
is particularly vulnerable to this kind of EMI (electro-magnetic
interference). If you know any old ham radio enthusiasts, or can
get on a blog or list-serve with a bunch of them, I'd bet you can
get some help pretty fast, and the hams would love to get under
the hood of your wheels.
There are reasons why the automobile manufacturer didn't shield,
ground and filter the car well. . . it reduces performance and adds
production costs! The additional filtering and shielding add weight
to the car, and the actual filtering components have an effect on
acceleration. There are two ways of filtering to reduce this kind
of noise, shunt (capacitance) and series (inductance). Either one
alone is only partially effective, one needs to employ both methods
to fully remediate such a problem. Each of these methods can possibly
have a detrimental effect on performance, since the shunt capacitors
slow down the rise- and fall-times of the A. C. waveforms in the
system, and adding series inductances reduces the available energy
to the motor through the insertion of resistance in the wiring,
which reduces the power that can be delivered to the motor during
acceleration. Certainly anything that is done to remediate the
noise problem will have an effect on performance, and the primary
goal of anyone attempting to improve your AM radio reception should
be to minimize this hit on performance.
Anyway, that's Grady's take on the electrical noise in the AM radio from the Roadsters's electronics. Now I will go away and leave this subject alone. :smile:
wiztecy
Active Member
I found out the antenna wire runs inside the tube of that ribbon that's affixed or band-aided to the passenger window column. I pulled the ribbon down and the gooo-eee tar that held it there, pulled the antenna out, and slide the antenna behind the crevice between the window and the column jam. I don't know why they didn't do that in the 1st place. I stuck some of the tar balls I pulled off up in there to use as a temporary sticky pad so that the wire doesn't pop back out. Will find something better as a sticky, then that'll make the Roadster look like a $100,000 car again 
[QUOTE= The problem is actually pretty simple, probably stemming from
having unshielded wiring and unfiltered goze-intas and comes-outas
where the wiring enters and leaves the various components in the
engine/controller system. (Like my high-tech terminology?)
electronics.
That's about as high tech as I get. :biggrin: I think it was in the old Andy Griffith movie, "No Time For Sergeants", where Andy is being interviewed by the psychiatrist, (Don Knotts), about his education, (math), Andy says that he was pretty good at his "Guzintas". :biggrin: For the old guys in the group.
having unshielded wiring and unfiltered goze-intas and comes-outas
where the wiring enters and leaves the various components in the
engine/controller system. (Like my high-tech terminology?)
electronics.
That's about as high tech as I get. :biggrin: I think it was in the old Andy Griffith movie, "No Time For Sergeants", where Andy is being interviewed by the psychiatrist, (Don Knotts), about his education, (math), Andy says that he was pretty good at his "Guzintas". :biggrin: For the old guys in the group.
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