Sirius antenna locations?

[Don Lancaster]

We just installed a Sirius system on our SUV and it works just fine.

But for some reason, they recommend putting the antenna as far to the
REAR of the vehicle as possible.

Why would they do this?

The only credible reason I can think of is that it might work slightly
better inside a garage or a carport.

Engine shielding? Possible feedback from the control box?

Also, their inline insertion adaptor totally trashes AM when powered.
I would think this could be avoided somehow.


--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[Joel Koltner]

Gee, Don, did you try the satellite radio group and find that it's 90+% people
arguing over whether XM or Sirius is better at the maturity level of a 6 year
old?

I've wondered the same thing about the antenna location and, trying it at lots
of different positions without any significant effect, my guess always has
been that some tech write asked some engineer, "Where should the antenna be
placed?," received the answer "on the rear of the vehicle is good," and decide
it was a lot more important than it really is. Hopefully we'll hear from
someone who knows for certain...

Also, their inline insertion adaptor totally trashes AM when powered.
I would think this could be avoided somehow.

Use a head unit that has line-level inputs? You definitely lose some fidelity
going through the antenna insertion route...

---Joel

 

[Joerg]

We just installed a Sirius system on our SUV and it works just fine.

But for some reason, they recommend putting the antenna as far to the
REAR of the vehicle as possible.

Why would they do this?

The only credible reason I can think of is that it might work slightly
better inside a garage or a carport.

Engine shielding? Possible feedback from the control box?

Not so much noise from the engine but all those little controllers under
the hood.Many aAutomotive EEs don't seem to be the experts when it comes
to EMI. Then there are all those cell phone yappers and, unfortunately,
those are mostly sitting in the driver seat which happens to be up front.

I have seen some gross stuff in automotive. For example bang-bang PWM of
windshield wiper motors. Chokes? Capacitors? Zilch.

Also, their inline insertion adaptor totally trashes AM when powered.
I would think this could be avoided somehow.

Either the designer was incompetent or he hated Rush Limbaugh ;-)

 

[Vladimir Vassilevsky]

Many aAutomotive EEs don't seem to be the experts when it comes
to EMI. Then there are all those cell phone yappers and, unfortunately,
those are mostly sitting in the driver seat which happens to be up front.

I have seen some gross stuff in automotive. For example bang-bang PWM of
windshield wiper motors. Chokes? Capacitors? Zilch.

I develop the OEM stuff for the automotive. The EMC and EMI requirements are
really hard. FCC Class B is a joke compared to that.

The aftermarket products are the completely different story. SMPS trashing
AM band is pretty much de-facto situation.

Vladimir Vassilevsky
DSP and Mixed Signal Consultant
www.abvolt.com

 

[Joerg]

I develop the OEM stuff for the automotive. The EMC and EMI requirements are
really hard. FCC Class B is a joke compared to that.

That may be so but I've seen lots of horrible performance. We used to be
able to make cars sputter or stall using ham radio transmitters. When I
bought my car I asked the dealer for the version with the least amount
of electronics in there.

 

[mpm]

We just installed a Sirius system on our SUV and it works just fine.

But for some reason, they recommend putting the antenna as far to the
REAR of the vehicle as possible.

Why would they do this?

The only credible reason I can think of is that it might work slightly
better inside a garage or a carport.

Engine shielding? Possible feedback from the control box?

Also, their inline insertion adaptor totally trashes AM when powered.
I would think this could be avoided somehow.

--
Many thanks,

Don Lancaster � � � � � � � � � � � � �voice phone: (928)428-4073
Synergetics � 3860 West First Street � Box 809 Thatcher, AZ 85552
rss:http://www.tinaja.com/whtnu.xml� email: [email protected]

Please visit my GURU's LAIR web site athttp://www.tinaja.com

My "guess" would be that locating the antenna as recommended would
minimize the length of exposed coax, and thus, serve to minimize
damage from car wash machines and the like.

I don't see any electrical or EMI issues involved here.
None of any consequence, that is.

-mpm

 

[Joel Koltner]

That may be so but I've seen lots of horrible performance. We used to be
able to make cars sputter or stall using ham radio transmitters.

I have a "GW Instek" (made in Taiwan) power supply that goes nuts (loses
regulation, output often hits the rails!) when you key up a 1W handheld radio
(on 2m) within a couple feet of it. :-(

Hopefully GW doesn't OEM automotive parts...

As I've suggested before, I think a big downfall in today's EE curriculum is
that The Digital Kids are often never given a chance to play with a spectrum
analyzer and see all the havoc that they can readily create...

 

[Joel Koltner]

"My "guess" would be that locating the antenna as recommended would
minimize the length of exposed coax, and thus, serve to minimize
damage from car wash machines and the like."

They do provide a little plastic "cover" that snaps over the top of the (very
small -- even smaller than RG-174) coax that has a think strip of "sticky
tape" on the bottom to try to protect it.

 

[Joerg]

I have a "GW Instek" (made in Taiwan) power supply that goes nuts (loses
regulation, output often hits the rails!) when you key up a 1W handheld radio
(on 2m) within a couple feet of it. :-(

I think it's designed in Taiwan but made in mainland China. Got a scope
from them and that holds up quite well. Actually better than a major oh
so famous US brand which is why I bought it.

A really bad example was a TDS220 that was spewing out so much conducted
noise from its backlight inverter or whatever that it had us fooled for
almost an hour. We started chasing 40/80kHz noise until we found out
that it didn't come from my circuit. Changed scopes, noise gone. Turned
TSD220 back on, noise clearly visible in other scope. Pathetic.

Hopefully GW doesn't OEM automotive parts...

As I've suggested before, I think a big downfall in today's EE curriculum is
that The Digital Kids are often never given a chance to play with a spectrum
analyzer and see all the havoc that they can readily create...

And that brings us older folks tons of work. Problem is, some day we'll
be too old for that.

 

[[email protected]]

We just installed a Sirius system on our SUV and it works just fine.

But for some reason, they recommend putting the antenna as far to the
REAR of the vehicle as possible.

Why would they do this?

The only credible reason I can think of is that it might work slightly
better inside a garage or a carport.

Engine shielding? Possible feedback from the control box?

Also, their inline insertion adaptor totally trashes AM when powered.
I would think this could be avoided somehow.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss:http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site athttp://www.tinaja.com

My XM antenna is mounted at the front of the vehicle. It is a through-
glass design. On the same vehicle, the Sirius antenna is mounted on
the roof, but still near the front of the vehicle.