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!FRENCH FRY!
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ok, so i've had my xm radio for probably bout 2-3 months now, just had the antenna mounted on the dash in the corner of the windshield. figured it was the quickest/easiest way to do it and everyone around that said they'd done the same had no problems with reception...well here in the LA area there's radio stations on most frequencies, and i finally got tired of havin to play with the thing to get the fm transmitter to come through on a station, so i mounted the antenna on the back of the roof where the hatch opens.

yay! awesome reception! just cruisin around the neighborhood, the reception is almost 100% clear vs. a bit staticky all the time before.

just a bit of random info for everyone, mounting it on the roof is a great solution and does make a difference, just took bout 15 minutes to tuck the wire under all the plastic peices and headliner, can't see but an inch or two of the wire at the back, just where it comes into the car.

anyone know what it takes to hardwire the reciever to the radio? so that it plays through the aux function rather than over the fm transmitter?
 

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sounds like you had an issue with the antenna affecting the fm transmitter and reception

i'm in the LA area with the antenna on the dash in the corner and rarely have problems. Never static, only dropped signal in certain areas. I have a direct connection though, not a fm transmitter. It's connected via AUX input on my Clarion HU. The Sirius tuner has a line-out.
 

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The satellite radio works on different frequencies (2.3GHz) than the FM transmitter (89 to 107MHz) will. That shouldn't be the issue with clarity between the transmitter and the head unit.

Most of the time in areas where the signal is stronger that you are using to broadcast your Sirius on FM that will interfer.

I have also noticed that if someone with satellite radio is close to you and broadcasting on the same frequency it will interfer.

Not exactly sure why relocating the satellite antenna would improve fm reception.

I too have it connected directly to the head unit. Tuner has an aux out, connects to the aux in (through an adapter) to the Pioneer headunit.
 

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I get perfect reception and my antenna is stuck by the opening in my hatch. I also use an XM ready pioneer head unit, so I direct connect too.
 

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remmargorp said:

Not exactly sure why relocating the satellite antenna would improve fm reception.
The FM signal is broadcast through the XM’s car antenna, not from the XM unit it self (when the XM car antenna is connected). This is the case with all XM receivers as far as I know.

More on topic: I see under your user name you have an 05 focus. I would recommend the AUX interface made by PIE: PIE model FRD04-AUX. LINK. The MSRP on the pie site is $103.95. I don’t know what it goes for now but I got it for about $75 when it came out. As I understand it, the reason it is so expensive is because it’s a strange digital interface, not a standard line-in that just needs an adaptor. I don’t know if any other companies have come out with a similar adapter yet.

Anyway it works great for me.

One thing I want to make clear is that the quality is phenomenal compared to using a crap ass built in FM modulator.

This was the orignal thread: http://www.focusfanatics.com/forum/showthread.php?s=&threadid=38596

PS: This mount is great for the radio it self:
 

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remmargorp said:
The satellite radio works on different frequencies (2.3GHz) than the FM transmitter (89 to 107MHz) will. That shouldn't be the issue with clarity between the transmitter and the head unit.

Most of the time in areas where the signal is stronger that you are using to broadcast your Sirius on FM that will interfer.

I have also noticed that if someone with satellite radio is close to you and broadcasting on the same frequency it will interfer.

Not exactly sure why relocating the satellite antenna would improve fm reception.

I too have it connected directly to the head unit. Tuner has an aux out, connects to the aux in (through an adapter) to the Pioneer headunit.
that is correct - it is actually impossible for a GHz Freq. to effect the 95mhz freq of FM radio, unless you had a coil of wire near the radio which in turn was picking up other frequency and thus causing a RF 'magnent' even if you blasted 100w of GHZ into a FM radio I would question the effects on the recption of the radio.
 

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Maybe I didn’t explain well enough. The satellite signal comes down from outer space and into your little mag-mount XM antenna where it goes through a little black wire all the way to your XM receiver. The XM receiver uses extra special fairy dust, known to humans as an “FM Modulator”, to turn the XM signal with all it’s jiga-hurtz and digital bliss into an and-a-log signal. It sends this primitive, lo-fi signal back trough the black wire to your mag-mount XM antenna where it goes screaming through the air at 186,000 miles per second to your cars antenna.

If it (your satelite antenna) is sitting on your plastic dash, crammed next to a support pillar for your roof, instead of situated on your roof, trunk, whatever, in the middle of a metal surface (at least 6 inches from an edge in order to give it a proper grounding plane)… then you will have both crappier reception of the satelite signal and crappier re-broadcast, of the low quality FM-modulated signal, to your FM radio.

In short; for the best reception (and rebroadcast if you must use an FM modulator instead of a direct line in), place your satellite antenna on your roof at least or about six inches from the nearest edge and close to your FM radios antenna if it is practical. Realisticly; living in a megalopolis like L.A., New York, San Francisco, or whatever, you are unlikely to find a station that will work without interference. And anyway, the difference in audio quality between a direct line in and the FM modulator is, to me, about the same difference as there is between a 56kbs MP3 and a 192kbs MP3.

P.S. I already know I’m an impatient ass hole.
 

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actually i dont belive that is correct. the FM transmit antenna is in the unit, the XM antenna is not condusive for MHZ signal nore is the wire that the antenna is hooked up with. that woudl be poor engineering. i coudl be proved wrong with a owners book but enginerring isnt on your side with your re-explination.
 

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spudgunman said:
actually i dont belive that is correct. the FM transmit antenna is in the unit, ...
THIS LINK will take you to a PDF for the Delphi XM MyFi Users guide. Go to page 31 and read the second "tip" in the grey box at the bottom of the page. It doesn't explicitly say it but it should be clear enough. If you absolutely won't believe me I will hunt down some more specific text.

To make my self clear, the unit does have an FM transmitter antenna in it. When it is docked in the car it uses the mag mount antenna to transmit its FM signal.

spudgunman said:
... the XM antenna is not condusive for MHZ signal nore is the wire that the antenna is hooked up with. that woudl be poor engineering.
If you think the conductor in the wire from the antenna is incapable of carrying two signals of different frequencies in opposite directions I would cite examples such as the coaxial cables used for TV (starting at 54MHz for VHF,to 470MHz for UHF and digital TV channels), broadband internet (650MHz range), and sometimes FM signals (standard 88-108MHz) all at the same time. The cable from the car dock to the antenna is a mini-coaxial cable. Also consider that the antenna element in the car antenna may be a 1:1 Standing Wave Ratio antenna for the 2.3GHz signal of the XM feed and be a 25:1 SWR antenna for the FM signal. This would severally handicap the FM transmission but FCC rules prohibit you from being able to transmit more than a few feet with an FM modulator. There may be a second antenna element inside the little black casing for the FM transmission. I’m not willing to dismantle mine to find out.

spudgunman said:
i coudl be proved wrong with a owners book but enginerring isnt on your side with your re-explination.
What kind of engineering background do you have?
 

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You did not need to goto page 31 for this information.

Read page 2

The Delphi XM MyFi Satellite Radio Receiver incorporates an
FM transmitter and is therefore classified as an intentional
transmitter. Changes or modifications to the unit not expressly
approved by Delphi can void your authority to operate this
equipment.
This is the particular design on the Delphi XM MyFi Satellite Radio, not the case for all satellite radios (for example, the Delphi Roady does not have this feature, but the SkyFi and MyFi do, the Directed Audio Sportster, Streamer and Starmate do not have that paticular functionality). So if he indeed does have an xm tuner that re-broadcasts its FM signal using the satellite antenna, then yes, relocating would have an effect.
 

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yes that wasnt really the "debate" is was if the antenna is located in the XM antenna. i have a SkyFi2 with the same features, i just didnt know that the MiFi actually bounces the FM back up the XM antenna

it started with the relocation then moved to nerdy arguments over design of which i didnt read the book first and just assumed Soong wins this round, ill get him later on ;)
 

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remmargorp said:
You did not need to goto page 31 for this information.

Read page 2



This is the particular design on the Delphi XM MyFi Satellite Radio, not the case for all satellite radios (for example, the Delphi Roady does not have this feature, but the SkyFi and MyFi do, the Directed Audio Sportster, Streamer and Starmate do not have that paticular functionality). So if he indeed does have an xm tuner that re-broadcasts its FM signal using the satellite antenna, then yes, relocating would have an effect.
Regardless of whether your satellite radio receiver has any kind of transmitter built into it or whether it sends such a signal through an integrated broadcast antenna or an external one; Having a proper ground plane for the receiving external antenna does affect reception. This is why it is a bad idea to put the antenna on the corner of your dash (wedged by the support pillar and under the windshield), and why the instructions for both Sirius and XM units both tell you to put your antenna on a metal surface (trunk, roof), and at least 6 inches from the nearest edge of that metal surface.

Ground plane and antennas are radio 101.

Before anyone calls me on it there are types of antennas that do not require a ground plane; don’t bet on that black lump of plastic on your car being one of them.

Edit/P.S.:
The Delphi XM MyFi Satellite Radio Receiver incorporates an
FM transmitter and is therefore classified as an intentional
transmitter
When it says "The Delphi XM MyFi Satellite Radio Receiver" it is referring to the radio it self as a receiver, not the external antenna; therefore this is/was not relevant to the discussion on weather the FM signal is broadcast through the external satellite antenna when it is connected to the satellite radio.
 
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