Old Crow

On Tue, 11 Sep 2007 10:13:33 -0400, Mike Romain <romainm@sympatico.ca>
wrote:

>XS11E wrote:
>> jeff <jalowe44.invalid@hotmail.com.invalid> wrote:
>>
>>> Any chassis ground is as effective as a separate ground lead.
>>> Metal to metal anywhere on a jeep should be less than an ohm.
>>
>> And that's EXACTLY why one isolates the antenna and CB in a Jeep to
>> avoid ground loops. Jeeps are notorious for not having good grounds,
>> particularly back in the days when CBs were more common. It was very
>> difficult to get a good noise free signal in Wagoneers and Cherokees
>> leading to the development of isolated mountings to avoid ground loops.
>>
>> Grounding the antenna to the body (as most installations do) is
>> surprisingly unsuccessful when the body grounds are rusted away.
>>
>>
>>
>
>If you use the vehicle chassis as a ground in a new GM vehicle, you will
>void the warranty for 'all' on board electronics of the vehicle. This
>includes things like the ABS controller, ignition, etc...
>
>You need to isolate transmitters these days.
>

Ain't that hard in a GM truck these days...nothing but plastic to
mount to anyway.
--
Old Crow "Yol Bolson!"
'82 FLTC-P "Miss Pearl"
'95 YJ Rio Grande
BS#133, SENS, TOMKAT, MAMBM


--
Posted via a free Usenet account from http://www.teranews.com

Mike Romain

L. Ron Waddle wrote:
> Mike Romain wrote:
>> A 'ground plane' is a reflective area for amplifying the signal.
>>
>> An 'electrical' ground is a power path.
>>
>> The 'only' thing they have in common is the word 'ground', nothing else.
>
> Well, except for the fact that all mobile antennas other than the "no
> ground plane" designs use the body as the ground plane and the body also
> serves as electrical ground. The car body is rather common between the two.

But 'totally' separate!

No ground plane simply means the antenna doesn't need a reflecting
surface to set it's SWR, 'not' it doesn't need an electrical hookup....

>
> I'm sorry, but when I want to know about radio electronics I read my
> ARRL handbook and the handbooks of the antenna and radio manufacturers.
> When I want to know about cars, I read GM and Ford handbooks. What GM
> and Ford know about CB (11 meter) radios could fit in the palm of my hand.

I have personally seen many ABS systems crap out from a bad install as
well as the digital dash and gauges and ignition in one case every time
the gent transmitted. This is in the fleet of about 200 delivery
vehicles I serviced.

I have personally seen GM void the warranty on 'very' new GM vans and
voided on one Ford van that kept 'blowing' trannies.

These arrogant folks that 'knew better than GM' very quickly took the
time after that from their 'too busy' of a schedule to have me properly
wire the transmitters in rather than use the cigarette lighter socket
they were 'insisting' on using.

Their lawsuit against the parent company I worked for, for vehicle
damages got dropped before it started because they were shown to be at
fault for being lazy and warned in writing of the potential consequences
of using the lighter plug.

A bad install in a TJ was reported here on this group as making the
tranny go into neutral every time the gent keyed up.
<snip where you got lucky with bad installs>

>
> So, why did I not run the ground wire to the battery? Simple. Adding an
> additional ground path to the battery risks fire if the body ground
> comes loose, because the antenna end of the coax is grounded to the
> body.

No, you are mistaken. The coax cable is 'physically' isolated from the
body at the antenna, it does 'not' act as an electrical route for DC power.

Please go look close at your antenna base. You will see a nylon insert
isolating the antenna base from the bracket. If you unscrew the coax at
the antenna and use a multimeter on continuity and put one probe on the
coax plug's male antenna end threads and on the vehicle body, you will
show an open circuit.

That is why the negative wire must be fused so the ground can't run
through the CB's 'chassis' ground and back feed into it's power line.

I was transmitting data packets with error correction. It was extremely
obvious when anyone's coax got frayed and 'electrically' grounded to the
vehicle body by the number of retries in the packets. I would get a
service call from the mainframe techs.

> In short, I am both puzzled and baffled by your objections to what every
> major radio and antenna manufacturer recommends. Perhaps you simply
> misunderstood what I was posting the first time? Hopefully this
> clarifies things then.

No, I 'have' to go by the 'Vehicle' manufacturers booklets to avoid 'me'
personally voiding someone's warranty and being liable for the damages
or the deaths that can and 'does' occur when the ABS module or tranny
module fails. (think van loaded to the roof with newspapers in a panic
stop and the 'expected' ABS fails)

I also 'had' to use Ericsson Canada's transmitter wiring specs which are
the same as GM's which is two 10 ga. wires both fused at the battery or
right at the power tap and main ground cable bolt.

I also worked with RIM (Research In Motion transmitters, think
blackberry guts) and their isolated antenna specs and power line specs
were the same as Ericsson's.

The long and short of it is whatever works for 'you' is fine, but if you
want to be above board and to avoid expensive 'no warranty' fixes on
your vehicle, you gotta do it 'their' way.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Mike Romain

L. Ron Waddle wrote:
> Mike Romain wrote:
>> A 'ground plane' is a reflective area for amplifying the signal.
>>
>> An 'electrical' ground is a power path.
>>
>> The 'only' thing they have in common is the word 'ground', nothing else.
>
> Well, except for the fact that all mobile antennas other than the "no
> ground plane" designs use the body as the ground plane and the body also
> serves as electrical ground. The car body is rather common between the two.

But 'totally' separate!

No ground plane simply means the antenna doesn't need a reflecting
surface to set it's SWR, 'not' it doesn't need an electrical hookup....

>
> I'm sorry, but when I want to know about radio electronics I read my
> ARRL handbook and the handbooks of the antenna and radio manufacturers.
> When I want to know about cars, I read GM and Ford handbooks. What GM
> and Ford know about CB (11 meter) radios could fit in the palm of my hand.

I have personally seen many ABS systems crap out from a bad install as
well as the digital dash and gauges and ignition in one case every time
the gent transmitted. This is in the fleet of about 200 delivery
vehicles I serviced.

I have personally seen GM void the warranty on 'very' new GM vans and
voided on one Ford van that kept 'blowing' trannies.

These arrogant folks that 'knew better than GM' very quickly took the
time after that from their 'too busy' of a schedule to have me properly
wire the transmitters in rather than use the cigarette lighter socket
they were 'insisting' on using.

Their lawsuit against the parent company I worked for, for vehicle
damages got dropped before it started because they were shown to be at
fault for being lazy and warned in writing of the potential consequences
of using the lighter plug.

A bad install in a TJ was reported here on this group as making the
tranny go into neutral every time the gent keyed up.
<snip where you got lucky with bad installs>

>
> So, why did I not run the ground wire to the battery? Simple. Adding an
> additional ground path to the battery risks fire if the body ground
> comes loose, because the antenna end of the coax is grounded to the
> body.

No, you are mistaken. The coax cable is 'physically' isolated from the
body at the antenna, it does 'not' act as an electrical route for DC power.

Please go look close at your antenna base. You will see a nylon insert
isolating the antenna base from the bracket. If you unscrew the coax at
the antenna and use a multimeter on continuity and put one probe on the
coax plug's male antenna end threads and on the vehicle body, you will
show an open circuit.

That is why the negative wire must be fused so the ground can't run
through the CB's 'chassis' ground and back feed into it's power line.

I was transmitting data packets with error correction. It was extremely
obvious when anyone's coax got frayed and 'electrically' grounded to the
vehicle body by the number of retries in the packets. I would get a
service call from the mainframe techs.

> In short, I am both puzzled and baffled by your objections to what every
> major radio and antenna manufacturer recommends. Perhaps you simply
> misunderstood what I was posting the first time? Hopefully this
> clarifies things then.

No, I 'have' to go by the 'Vehicle' manufacturers booklets to avoid 'me'
personally voiding someone's warranty and being liable for the damages
or the deaths that can and 'does' occur when the ABS module or tranny
module fails. (think van loaded to the roof with newspapers in a panic
stop and the 'expected' ABS fails)

I also 'had' to use Ericsson Canada's transmitter wiring specs which are
the same as GM's which is two 10 ga. wires both fused at the battery or
right at the power tap and main ground cable bolt.

I also worked with RIM (Research In Motion transmitters, think
blackberry guts) and their isolated antenna specs and power line specs
were the same as Ericsson's.

The long and short of it is whatever works for 'you' is fine, but if you
want to be above board and to avoid expensive 'no warranty' fixes on
your vehicle, you gotta do it 'their' way.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Mike Romain

L. Ron Waddle wrote:
> Mike Romain wrote:
>> A 'ground plane' is a reflective area for amplifying the signal.
>>
>> An 'electrical' ground is a power path.
>>
>> The 'only' thing they have in common is the word 'ground', nothing else.
>
> Well, except for the fact that all mobile antennas other than the "no
> ground plane" designs use the body as the ground plane and the body also
> serves as electrical ground. The car body is rather common between the two.

But 'totally' separate!

No ground plane simply means the antenna doesn't need a reflecting
surface to set it's SWR, 'not' it doesn't need an electrical hookup....

>
> I'm sorry, but when I want to know about radio electronics I read my
> ARRL handbook and the handbooks of the antenna and radio manufacturers.
> When I want to know about cars, I read GM and Ford handbooks. What GM
> and Ford know about CB (11 meter) radios could fit in the palm of my hand.

I have personally seen many ABS systems crap out from a bad install as
well as the digital dash and gauges and ignition in one case every time
the gent transmitted. This is in the fleet of about 200 delivery
vehicles I serviced.

I have personally seen GM void the warranty on 'very' new GM vans and
voided on one Ford van that kept 'blowing' trannies.

These arrogant folks that 'knew better than GM' very quickly took the
time after that from their 'too busy' of a schedule to have me properly
wire the transmitters in rather than use the cigarette lighter socket
they were 'insisting' on using.

Their lawsuit against the parent company I worked for, for vehicle
damages got dropped before it started because they were shown to be at
fault for being lazy and warned in writing of the potential consequences
of using the lighter plug.

A bad install in a TJ was reported here on this group as making the
tranny go into neutral every time the gent keyed up.
<snip where you got lucky with bad installs>

>
> So, why did I not run the ground wire to the battery? Simple. Adding an
> additional ground path to the battery risks fire if the body ground
> comes loose, because the antenna end of the coax is grounded to the
> body.

No, you are mistaken. The coax cable is 'physically' isolated from the
body at the antenna, it does 'not' act as an electrical route for DC power.

Please go look close at your antenna base. You will see a nylon insert
isolating the antenna base from the bracket. If you unscrew the coax at
the antenna and use a multimeter on continuity and put one probe on the
coax plug's male antenna end threads and on the vehicle body, you will
show an open circuit.

That is why the negative wire must be fused so the ground can't run
through the CB's 'chassis' ground and back feed into it's power line.

I was transmitting data packets with error correction. It was extremely
obvious when anyone's coax got frayed and 'electrically' grounded to the
vehicle body by the number of retries in the packets. I would get a
service call from the mainframe techs.

> In short, I am both puzzled and baffled by your objections to what every
> major radio and antenna manufacturer recommends. Perhaps you simply
> misunderstood what I was posting the first time? Hopefully this
> clarifies things then.

No, I 'have' to go by the 'Vehicle' manufacturers booklets to avoid 'me'
personally voiding someone's warranty and being liable for the damages
or the deaths that can and 'does' occur when the ABS module or tranny
module fails. (think van loaded to the roof with newspapers in a panic
stop and the 'expected' ABS fails)

I also 'had' to use Ericsson Canada's transmitter wiring specs which are
the same as GM's which is two 10 ga. wires both fused at the battery or
right at the power tap and main ground cable bolt.

I also worked with RIM (Research In Motion transmitters, think
blackberry guts) and their isolated antenna specs and power line specs
were the same as Ericsson's.

The long and short of it is whatever works for 'you' is fine, but if you
want to be above board and to avoid expensive 'no warranty' fixes on
your vehicle, you gotta do it 'their' way.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

Mike Romain

L. Ron Waddle wrote:
> Mike Romain wrote:
>> A 'ground plane' is a reflective area for amplifying the signal.
>>
>> An 'electrical' ground is a power path.
>>
>> The 'only' thing they have in common is the word 'ground', nothing else.
>
> Well, except for the fact that all mobile antennas other than the "no
> ground plane" designs use the body as the ground plane and the body also
> serves as electrical ground. The car body is rather common between the two.

But 'totally' separate!

No ground plane simply means the antenna doesn't need a reflecting
surface to set it's SWR, 'not' it doesn't need an electrical hookup....

>
> I'm sorry, but when I want to know about radio electronics I read my
> ARRL handbook and the handbooks of the antenna and radio manufacturers.
> When I want to know about cars, I read GM and Ford handbooks. What GM
> and Ford know about CB (11 meter) radios could fit in the palm of my hand.

I have personally seen many ABS systems crap out from a bad install as
well as the digital dash and gauges and ignition in one case every time
the gent transmitted. This is in the fleet of about 200 delivery
vehicles I serviced.

I have personally seen GM void the warranty on 'very' new GM vans and
voided on one Ford van that kept 'blowing' trannies.

These arrogant folks that 'knew better than GM' very quickly took the
time after that from their 'too busy' of a schedule to have me properly
wire the transmitters in rather than use the cigarette lighter socket
they were 'insisting' on using.

Their lawsuit against the parent company I worked for, for vehicle
damages got dropped before it started because they were shown to be at
fault for being lazy and warned in writing of the potential consequences
of using the lighter plug.

A bad install in a TJ was reported here on this group as making the
tranny go into neutral every time the gent keyed up.
<snip where you got lucky with bad installs>

>
> So, why did I not run the ground wire to the battery? Simple. Adding an
> additional ground path to the battery risks fire if the body ground
> comes loose, because the antenna end of the coax is grounded to the
> body.

No, you are mistaken. The coax cable is 'physically' isolated from the
body at the antenna, it does 'not' act as an electrical route for DC power.

Please go look close at your antenna base. You will see a nylon insert
isolating the antenna base from the bracket. If you unscrew the coax at
the antenna and use a multimeter on continuity and put one probe on the
coax plug's male antenna end threads and on the vehicle body, you will
show an open circuit.

That is why the negative wire must be fused so the ground can't run
through the CB's 'chassis' ground and back feed into it's power line.

I was transmitting data packets with error correction. It was extremely
obvious when anyone's coax got frayed and 'electrically' grounded to the
vehicle body by the number of retries in the packets. I would get a
service call from the mainframe techs.

> In short, I am both puzzled and baffled by your objections to what every
> major radio and antenna manufacturer recommends. Perhaps you simply
> misunderstood what I was posting the first time? Hopefully this
> clarifies things then.

No, I 'have' to go by the 'Vehicle' manufacturers booklets to avoid 'me'
personally voiding someone's warranty and being liable for the damages
or the deaths that can and 'does' occur when the ABS module or tranny
module fails. (think van loaded to the roof with newspapers in a panic
stop and the 'expected' ABS fails)

I also 'had' to use Ericsson Canada's transmitter wiring specs which are
the same as GM's which is two 10 ga. wires both fused at the battery or
right at the power tap and main ground cable bolt.

I also worked with RIM (Research In Motion transmitters, think
blackberry guts) and their isolated antenna specs and power line specs
were the same as Ericsson's.

The long and short of it is whatever works for 'you' is fine, but if you
want to be above board and to avoid expensive 'no warranty' fixes on
your vehicle, you gotta do it 'their' way.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

L. Ron Waddle

Mike Romain wrote:
> L. Ron Waddle wrote:
>> Mike Romain wrote:
>>> A 'ground plane' is a reflective area for amplifying the signal.
>>>
>>> An 'electrical' ground is a power path.
>>>
>>> The 'only' thing they have in common is the word 'ground', nothing else.
>>
>> Well, except for the fact that all mobile antennas other than the "no
>> ground plane" designs use the body as the ground plane and the body
>> also serves as electrical ground. The car body is rather common
>> between the two.
>
> But 'totally' separate!
>
> No ground plane simply means the antenna doesn't need a reflecting
> surface to set it's SWR, 'not' it doesn't need an electrical hookup....

I'm not understanding what you're talking about. You seem to be
confused. SWR is a rating of how much power is reflected from the end of
the antenna back to the transmitter as harmonics instead of radiating to
the airwaves. Reflected power ("standing waves") a) causes the
transmission to sound garbled (since additional wavelengths are
introduced into the amplitude-modulated output), and b) can damage the
input capacitor or output amplifier on the transmitter. The secret to
avoid standing waves is to carefully tune the length of your
transmission chain in order that your power be radiated rather than
reflected back. A poor ground plane (reflecting surface) can certainly
cause SWR's to be high, since this causes power to be reflected back to
the antenna rather than out to the intended destination, but is not by
any means the only cause of high SWR's.

The biggest cause of high SWR's is the fact that typically other parts
of the transmission chain are radiating or are of a length that is
chopping up your waves as they head for the tip of the antenna. Thus if
your coax is not shielded with the shielding grounded properly at both
ends, your coax length should be a half-wave or quarter-wave in length.
For 11 meter band (CB radio), that's 8.25 feet if you want a quarter
wave coax. If the shielding on your coax is not grounded to a hard
ground at both ends, your coax becomes an antenna, and this makes it
harder to adjust your SWR's unless you are quite adept at tuning
combined cable-antenna combinations. That is why the "no ground plane"
setups require a specially tuned cable-antenna combination to work
properly, it isn't necessarily because of lack of a ground plane (I have
seen a regular Firestick work just fine on a 4-wheeler with very little
reflective surface), but, rather, because due to inability to pull a
hard ground on the shielding of the coax on both ends, the coax is now
part of the antenna.

>
>>
>> I'm sorry, but when I want to know about radio electronics I read my
>> ARRL handbook and the handbooks of the antenna and radio
>> manufacturers. When I want to know about cars, I read GM and Ford
>> handbooks. What GM and Ford know about CB (11 meter) radios could fit
>> in the palm of my hand.
>
> I have personally seen many ABS systems crap out from a bad install as
> well as the digital dash and gauges and ignition in one case every time
> the gent transmitted. This is in the fleet of about 200 delivery
> vehicles I serviced.

With a 5 watt CB radio? I'm going to call BS on you. Not that I'm
worried about that, since, like every Jeep TJ I've ever seen, my Jeep TJ
doesn't have ABS.


> I have personally seen GM void the warranty on 'very' new GM vans and
> voided on one Ford van that kept 'blowing' trannies.

Maybe that's legal in Canada. Here in the U.S., they have to prove that
your install caused the problem, or you have a lawsuit against them for
breach of the Magnuson-Moss Warranty Act.

>> So, why did I not run the ground wire to the battery? Simple. Adding
>> an additional ground path to the battery risks fire if the body ground
>> comes loose, because the antenna end of the coax is grounded to the body.
>
> No, you are mistaken. The coax cable is 'physically' isolated from the
> body at the antenna, it does 'not' act as an electrical route for DC power.

The *SHIELDING* of the coax cable is grounded at both ends. (Rolls
eyes). Otherwise the coax cable becomes part of the antenna and must be
carefully tuned in length. You are correct that the center portion is
isolated. Otherwise the antenna wouldn't work, since the whole point of
an antenna is to bounce AM-modulated radio waves off the end of the
thing, and if it's grounded obviously that's not happening! I realize
that American "English" and Canadian "English" are not identical, but we
appear to be speaking foreign tongues to each other here, from what
little understanding is making it out.

If the coax is not properly grounded at both ends (again, I am talking
about the SHIELDING part of the coax, not the CENTER part -- a coax has
*TWO* things in it that carry electricity, doh!), your likely result is
to be high SWR's. And the ground on both ends has to be to a ground
that's at the exact same potential on both ends and said ground has to
be the same ground as the transmitter because the transmitter is
bouncing its waves courtesy of said ground.

> I was transmitting data packets with error correction. It was extremely

On CB radio?! That may be legal in Canuckstan, but CB radio here in the
USA is only allowed to be used for voice transmission.

> obvious when anyone's coax got frayed and 'electrically' grounded to the
> vehicle body by the number of retries in the packets. I would get a
> service call from the mainframe techs.

If your coax ground is not the same as your body ground that certainly
can happen. (The coax ground is the *SHIELDING* ground, once again). You
are then flowing a current through your shielding and inducing
distortion in AC flow in the center conductor (doh, it's called
*induction*, and is the whole thing that makes AC power generation work!).

The best way to make sure this does not happen is to make sure that both
ends of your coax ground, and your CB radio ground, are grounded to a
common ground. Grounding it to the steel body of a Jeep TJ certainly
works to insure that all of these are using a common ground. But if you
add a second ground path for just two parts of the equation (i.e., for
the radio end of the coax and for the radio itself), you do not insure
that you have a common ground, thus can have a ground loop through the
coax shielding with resulting distortion. In particular, if the body
ground wire from the battery to the body goes bad, then everything
*else* grounded to the body is now going to use your radio ground
through the coax shielding. Coax shielding isn't designed to carry a lot
of power.

In non-metallic vehicles such as fiberglass boats, or on vehicles where
the frame cannot be used for grounding such as on aluminum-framed
motorcycles with steel components bolted to the frame (electricity
flowing through an aluminum-steel junction causes corrosion), generally
there is a separate "ground distribution panel" similar to the power
distribution panel. The ground from the battery goes to this "ground
distribution panel" from whence individual ground wires go to the
individual appliances that need power. This is how ground loops are
avoided on these kinds of vehicles. To avoid ground loops, you need
*ONE* wire to the battery ground to a distribution point, then *all*
appliances and applications must connect to that single distribution
point. On my Jeep TJ that single distribution point is the body itself
(or if you want to be picky, the point at which the cable from the
battery connects to the body). Adding additional ground paths is unwise
because, even with a fuse, it adds the possibility of fire if any point
in all possible ground loop paths will not carry enough power to blow
that fuse.

This is Electrical 101. This isn't rocket science. We've known this in
the electrical field ever since the days of ****-and-tube wiring in the
early days of the 20th century where it was discovered the hard way that
a common distribution ground panel was the only way to prevent the
"earth" from causing a fire (early ****-and-tube installations simply
had a ground "bus" that ran to the "earth" on all the plugs). It's
pathetic that anybody would even argue different 100 years after the
issue was settled conclusively.

>> In short, I am both puzzled and baffled by your objections to what
>> every major radio and antenna manufacturer recommends. Perhaps you
>> simply misunderstood what I was posting the first time? Hopefully this
>> clarifies things then.
>
> No, I 'have' to go by the 'Vehicle' manufacturers booklets to avoid 'me'

Somehow I think catching the vehicle on fire by installing it via a
method which violates 100 years of electrical codes might also voide the
warranty (grin!).

> I also worked with RIM (Research In Motion transmitters, think
> blackberry guts) and their isolated antenna specs and power line specs
> were the same as Ericsson's.

Please note that these are *NOT* the same as CB radios. You are talking
about cellular frequencies, which are very short waves compared to CB
waves. CB is in the 11 meter band. 850mhz (the longest-wavelength
cellular communication) is in the 0.35 meter band (yep, that's 35
centimeter band). The coax length in a CB installation is shorter than
the wavelength of the transmitted radio signal, the coax length in a
cellular radio is longer than the wavelength of the transmitted radio
signal. The end result is that it is much, much easier to tune the coax
length for ultra-shortwave frequencies, and you can dispense with the
grounded shielding required for good results with CB radio. In addition,
850mhz causes much more impact upon car electronics because this is
close to the frequency that modern computers operate at. This is *NOT*
true of CB radio, which operates on the 11 meter band (that's the 27
megahertz band in case you're wondering). You appear to be holding an
orange and declaring that all fruits are citrus. That is not, however,
the case. The needs of an 850mhz antenna install are far different from
those of a 27mhz antenna install, because the wavelengths (35cm vs. 11
meter) are far different.

> The long and short of it is whatever works for 'you' is fine, but if you
> want to be above board and to avoid expensive 'no warranty' fixes on
> your vehicle, you gotta do it 'their' way.

Please note that a) your "warranty" issues are specific to Canada and do
not apply to the United States where we have consumer protection laws to
prohibit manufacturers from arbitrarily denying warranty coverage for
irrelevant reasons, and b) your installation pointers are applicable to
the 35 centimeter band and do not apply to the 11 meter band, which
requires shielded coax grounded at both ends to a common ground with the
transmitter ground for best results. Please do not confuse the needs of
installing an 850mhz transmitter with the needs of installing a 27mhz
transmitter. Thank you.


-Elron

L. Ron Waddle

Mike Romain wrote:
> L. Ron Waddle wrote:
>> Mike Romain wrote:
>>> A 'ground plane' is a reflective area for amplifying the signal.
>>>
>>> An 'electrical' ground is a power path.
>>>
>>> The 'only' thing they have in common is the word 'ground', nothing else.
>>
>> Well, except for the fact that all mobile antennas other than the "no
>> ground plane" designs use the body as the ground plane and the body
>> also serves as electrical ground. The car body is rather common
>> between the two.
>
> But 'totally' separate!
>
> No ground plane simply means the antenna doesn't need a reflecting
> surface to set it's SWR, 'not' it doesn't need an electrical hookup....

I'm not understanding what you're talking about. You seem to be
confused. SWR is a rating of how much power is reflected from the end of
the antenna back to the transmitter as harmonics instead of radiating to
the airwaves. Reflected power ("standing waves") a) causes the
transmission to sound garbled (since additional wavelengths are
introduced into the amplitude-modulated output), and b) can damage the
input capacitor or output amplifier on the transmitter. The secret to
avoid standing waves is to carefully tune the length of your
transmission chain in order that your power be radiated rather than
reflected back. A poor ground plane (reflecting surface) can certainly
cause SWR's to be high, since this causes power to be reflected back to
the antenna rather than out to the intended destination, but is not by
any means the only cause of high SWR's.

The biggest cause of high SWR's is the fact that typically other parts
of the transmission chain are radiating or are of a length that is
chopping up your waves as they head for the tip of the antenna. Thus if
your coax is not shielded with the shielding grounded properly at both
ends, your coax length should be a half-wave or quarter-wave in length.
For 11 meter band (CB radio), that's 8.25 feet if you want a quarter
wave coax. If the shielding on your coax is not grounded to a hard
ground at both ends, your coax becomes an antenna, and this makes it
harder to adjust your SWR's unless you are quite adept at tuning
combined cable-antenna combinations. That is why the "no ground plane"
setups require a specially tuned cable-antenna combination to work
properly, it isn't necessarily because of lack of a ground plane (I have
seen a regular Firestick work just fine on a 4-wheeler with very little
reflective surface), but, rather, because due to inability to pull a
hard ground on the shielding of the coax on both ends, the coax is now
part of the antenna.

>
>>
>> I'm sorry, but when I want to know about radio electronics I read my
>> ARRL handbook and the handbooks of the antenna and radio
>> manufacturers. When I want to know about cars, I read GM and Ford
>> handbooks. What GM and Ford know about CB (11 meter) radios could fit
>> in the palm of my hand.
>
> I have personally seen many ABS systems crap out from a bad install as
> well as the digital dash and gauges and ignition in one case every time
> the gent transmitted. This is in the fleet of about 200 delivery
> vehicles I serviced.

With a 5 watt CB radio? I'm going to call BS on you. Not that I'm
worried about that, since, like every Jeep TJ I've ever seen, my Jeep TJ
doesn't have ABS.


> I have personally seen GM void the warranty on 'very' new GM vans and
> voided on one Ford van that kept 'blowing' trannies.

Maybe that's legal in Canada. Here in the U.S., they have to prove that
your install caused the problem, or you have a lawsuit against them for
breach of the Magnuson-Moss Warranty Act.

>> So, why did I not run the ground wire to the battery? Simple. Adding
>> an additional ground path to the battery risks fire if the body ground
>> comes loose, because the antenna end of the coax is grounded to the body.
>
> No, you are mistaken. The coax cable is 'physically' isolated from the
> body at the antenna, it does 'not' act as an electrical route for DC power.

The *SHIELDING* of the coax cable is grounded at both ends. (Rolls
eyes). Otherwise the coax cable becomes part of the antenna and must be
carefully tuned in length. You are correct that the center portion is
isolated. Otherwise the antenna wouldn't work, since the whole point of
an antenna is to bounce AM-modulated radio waves off the end of the
thing, and if it's grounded obviously that's not happening! I realize
that American "English" and Canadian "English" are not identical, but we
appear to be speaking foreign tongues to each other here, from what
little understanding is making it out.

If the coax is not properly grounded at both ends (again, I am talking
about the SHIELDING part of the coax, not the CENTER part -- a coax has
*TWO* things in it that carry electricity, doh!), your likely result is
to be high SWR's. And the ground on both ends has to be to a ground
that's at the exact same potential on both ends and said ground has to
be the same ground as the transmitter because the transmitter is
bouncing its waves courtesy of said ground.

> I was transmitting data packets with error correction. It was extremely

On CB radio?! That may be legal in Canuckstan, but CB radio here in the
USA is only allowed to be used for voice transmission.

> obvious when anyone's coax got frayed and 'electrically' grounded to the
> vehicle body by the number of retries in the packets. I would get a
> service call from the mainframe techs.

If your coax ground is not the same as your body ground that certainly
can happen. (The coax ground is the *SHIELDING* ground, once again). You
are then flowing a current through your shielding and inducing
distortion in AC flow in the center conductor (doh, it's called
*induction*, and is the whole thing that makes AC power generation work!).

The best way to make sure this does not happen is to make sure that both
ends of your coax ground, and your CB radio ground, are grounded to a
common ground. Grounding it to the steel body of a Jeep TJ certainly
works to insure that all of these are using a common ground. But if you
add a second ground path for just two parts of the equation (i.e., for
the radio end of the coax and for the radio itself), you do not insure
that you have a common ground, thus can have a ground loop through the
coax shielding with resulting distortion. In particular, if the body
ground wire from the battery to the body goes bad, then everything
*else* grounded to the body is now going to use your radio ground
through the coax shielding. Coax shielding isn't designed to carry a lot
of power.

In non-metallic vehicles such as fiberglass boats, or on vehicles where
the frame cannot be used for grounding such as on aluminum-framed
motorcycles with steel components bolted to the frame (electricity
flowing through an aluminum-steel junction causes corrosion), generally
there is a separate "ground distribution panel" similar to the power
distribution panel. The ground from the battery goes to this "ground
distribution panel" from whence individual ground wires go to the
individual appliances that need power. This is how ground loops are
avoided on these kinds of vehicles. To avoid ground loops, you need
*ONE* wire to the battery ground to a distribution point, then *all*
appliances and applications must connect to that single distribution
point. On my Jeep TJ that single distribution point is the body itself
(or if you want to be picky, the point at which the cable from the
battery connects to the body). Adding additional ground paths is unwise
because, even with a fuse, it adds the possibility of fire if any point
in all possible ground loop paths will not carry enough power to blow
that fuse.

This is Electrical 101. This isn't rocket science. We've known this in
the electrical field ever since the days of ****-and-tube wiring in the
early days of the 20th century where it was discovered the hard way that
a common distribution ground panel was the only way to prevent the
"earth" from causing a fire (early ****-and-tube installations simply
had a ground "bus" that ran to the "earth" on all the plugs). It's
pathetic that anybody would even argue different 100 years after the
issue was settled conclusively.

>> In short, I am both puzzled and baffled by your objections to what
>> every major radio and antenna manufacturer recommends. Perhaps you
>> simply misunderstood what I was posting the first time? Hopefully this
>> clarifies things then.
>
> No, I 'have' to go by the 'Vehicle' manufacturers booklets to avoid 'me'

Somehow I think catching the vehicle on fire by installing it via a
method which violates 100 years of electrical codes might also voide the
warranty (grin!).

> I also worked with RIM (Research In Motion transmitters, think
> blackberry guts) and their isolated antenna specs and power line specs
> were the same as Ericsson's.

Please note that these are *NOT* the same as CB radios. You are talking
about cellular frequencies, which are very short waves compared to CB
waves. CB is in the 11 meter band. 850mhz (the longest-wavelength
cellular communication) is in the 0.35 meter band (yep, that's 35
centimeter band). The coax length in a CB installation is shorter than
the wavelength of the transmitted radio signal, the coax length in a
cellular radio is longer than the wavelength of the transmitted radio
signal. The end result is that it is much, much easier to tune the coax
length for ultra-shortwave frequencies, and you can dispense with the
grounded shielding required for good results with CB radio. In addition,
850mhz causes much more impact upon car electronics because this is
close to the frequency that modern computers operate at. This is *NOT*
true of CB radio, which operates on the 11 meter band (that's the 27
megahertz band in case you're wondering). You appear to be holding an
orange and declaring that all fruits are citrus. That is not, however,
the case. The needs of an 850mhz antenna install are far different from
those of a 27mhz antenna install, because the wavelengths (35cm vs. 11
meter) are far different.

> The long and short of it is whatever works for 'you' is fine, but if you
> want to be above board and to avoid expensive 'no warranty' fixes on
> your vehicle, you gotta do it 'their' way.

Please note that a) your "warranty" issues are specific to Canada and do
not apply to the United States where we have consumer protection laws to
prohibit manufacturers from arbitrarily denying warranty coverage for
irrelevant reasons, and b) your installation pointers are applicable to
the 35 centimeter band and do not apply to the 11 meter band, which
requires shielded coax grounded at both ends to a common ground with the
transmitter ground for best results. Please do not confuse the needs of
installing an 850mhz transmitter with the needs of installing a 27mhz
transmitter. Thank you.


-Elron

L. Ron Waddle

Mike Romain wrote:
> L. Ron Waddle wrote:
>> Mike Romain wrote:
>>> A 'ground plane' is a reflective area for amplifying the signal.
>>>
>>> An 'electrical' ground is a power path.
>>>
>>> The 'only' thing they have in common is the word 'ground', nothing else.
>>
>> Well, except for the fact that all mobile antennas other than the "no
>> ground plane" designs use the body as the ground plane and the body
>> also serves as electrical ground. The car body is rather common
>> between the two.
>
> But 'totally' separate!
>
> No ground plane simply means the antenna doesn't need a reflecting
> surface to set it's SWR, 'not' it doesn't need an electrical hookup....

I'm not understanding what you're talking about. You seem to be
confused. SWR is a rating of how much power is reflected from the end of
the antenna back to the transmitter as harmonics instead of radiating to
the airwaves. Reflected power ("standing waves") a) causes the
transmission to sound garbled (since additional wavelengths are
introduced into the amplitude-modulated output), and b) can damage the
input capacitor or output amplifier on the transmitter. The secret to
avoid standing waves is to carefully tune the length of your
transmission chain in order that your power be radiated rather than
reflected back. A poor ground plane (reflecting surface) can certainly
cause SWR's to be high, since this causes power to be reflected back to
the antenna rather than out to the intended destination, but is not by
any means the only cause of high SWR's.

The biggest cause of high SWR's is the fact that typically other parts
of the transmission chain are radiating or are of a length that is
chopping up your waves as they head for the tip of the antenna. Thus if
your coax is not shielded with the shielding grounded properly at both
ends, your coax length should be a half-wave or quarter-wave in length.
For 11 meter band (CB radio), that's 8.25 feet if you want a quarter
wave coax. If the shielding on your coax is not grounded to a hard
ground at both ends, your coax becomes an antenna, and this makes it
harder to adjust your SWR's unless you are quite adept at tuning
combined cable-antenna combinations. That is why the "no ground plane"
setups require a specially tuned cable-antenna combination to work
properly, it isn't necessarily because of lack of a ground plane (I have
seen a regular Firestick work just fine on a 4-wheeler with very little
reflective surface), but, rather, because due to inability to pull a
hard ground on the shielding of the coax on both ends, the coax is now
part of the antenna.

>
>>
>> I'm sorry, but when I want to know about radio electronics I read my
>> ARRL handbook and the handbooks of the antenna and radio
>> manufacturers. When I want to know about cars, I read GM and Ford
>> handbooks. What GM and Ford know about CB (11 meter) radios could fit
>> in the palm of my hand.
>
> I have personally seen many ABS systems crap out from a bad install as
> well as the digital dash and gauges and ignition in one case every time
> the gent transmitted. This is in the fleet of about 200 delivery
> vehicles I serviced.

With a 5 watt CB radio? I'm going to call BS on you. Not that I'm
worried about that, since, like every Jeep TJ I've ever seen, my Jeep TJ
doesn't have ABS.


> I have personally seen GM void the warranty on 'very' new GM vans and
> voided on one Ford van that kept 'blowing' trannies.

Maybe that's legal in Canada. Here in the U.S., they have to prove that
your install caused the problem, or you have a lawsuit against them for
breach of the Magnuson-Moss Warranty Act.

>> So, why did I not run the ground wire to the battery? Simple. Adding
>> an additional ground path to the battery risks fire if the body ground
>> comes loose, because the antenna end of the coax is grounded to the body.
>
> No, you are mistaken. The coax cable is 'physically' isolated from the
> body at the antenna, it does 'not' act as an electrical route for DC power.

The *SHIELDING* of the coax cable is grounded at both ends. (Rolls
eyes). Otherwise the coax cable becomes part of the antenna and must be
carefully tuned in length. You are correct that the center portion is
isolated. Otherwise the antenna wouldn't work, since the whole point of
an antenna is to bounce AM-modulated radio waves off the end of the
thing, and if it's grounded obviously that's not happening! I realize
that American "English" and Canadian "English" are not identical, but we
appear to be speaking foreign tongues to each other here, from what
little understanding is making it out.

If the coax is not properly grounded at both ends (again, I am talking
about the SHIELDING part of the coax, not the CENTER part -- a coax has
*TWO* things in it that carry electricity, doh!), your likely result is
to be high SWR's. And the ground on both ends has to be to a ground
that's at the exact same potential on both ends and said ground has to
be the same ground as the transmitter because the transmitter is
bouncing its waves courtesy of said ground.

> I was transmitting data packets with error correction. It was extremely

On CB radio?! That may be legal in Canuckstan, but CB radio here in the
USA is only allowed to be used for voice transmission.

> obvious when anyone's coax got frayed and 'electrically' grounded to the
> vehicle body by the number of retries in the packets. I would get a
> service call from the mainframe techs.

If your coax ground is not the same as your body ground that certainly
can happen. (The coax ground is the *SHIELDING* ground, once again). You
are then flowing a current through your shielding and inducing
distortion in AC flow in the center conductor (doh, it's called
*induction*, and is the whole thing that makes AC power generation work!).

The best way to make sure this does not happen is to make sure that both
ends of your coax ground, and your CB radio ground, are grounded to a
common ground. Grounding it to the steel body of a Jeep TJ certainly
works to insure that all of these are using a common ground. But if you
add a second ground path for just two parts of the equation (i.e., for
the radio end of the coax and for the radio itself), you do not insure
that you have a common ground, thus can have a ground loop through the
coax shielding with resulting distortion. In particular, if the body
ground wire from the battery to the body goes bad, then everything
*else* grounded to the body is now going to use your radio ground
through the coax shielding. Coax shielding isn't designed to carry a lot
of power.

In non-metallic vehicles such as fiberglass boats, or on vehicles where
the frame cannot be used for grounding such as on aluminum-framed
motorcycles with steel components bolted to the frame (electricity
flowing through an aluminum-steel junction causes corrosion), generally
there is a separate "ground distribution panel" similar to the power
distribution panel. The ground from the battery goes to this "ground
distribution panel" from whence individual ground wires go to the
individual appliances that need power. This is how ground loops are
avoided on these kinds of vehicles. To avoid ground loops, you need
*ONE* wire to the battery ground to a distribution point, then *all*
appliances and applications must connect to that single distribution
point. On my Jeep TJ that single distribution point is the body itself
(or if you want to be picky, the point at which the cable from the
battery connects to the body). Adding additional ground paths is unwise
because, even with a fuse, it adds the possibility of fire if any point
in all possible ground loop paths will not carry enough power to blow
that fuse.

This is Electrical 101. This isn't rocket science. We've known this in
the electrical field ever since the days of ****-and-tube wiring in the
early days of the 20th century where it was discovered the hard way that
a common distribution ground panel was the only way to prevent the
"earth" from causing a fire (early ****-and-tube installations simply
had a ground "bus" that ran to the "earth" on all the plugs). It's
pathetic that anybody would even argue different 100 years after the
issue was settled conclusively.

>> In short, I am both puzzled and baffled by your objections to what
>> every major radio and antenna manufacturer recommends. Perhaps you
>> simply misunderstood what I was posting the first time? Hopefully this
>> clarifies things then.
>
> No, I 'have' to go by the 'Vehicle' manufacturers booklets to avoid 'me'

Somehow I think catching the vehicle on fire by installing it via a
method which violates 100 years of electrical codes might also voide the
warranty (grin!).

> I also worked with RIM (Research In Motion transmitters, think
> blackberry guts) and their isolated antenna specs and power line specs
> were the same as Ericsson's.

Please note that these are *NOT* the same as CB radios. You are talking
about cellular frequencies, which are very short waves compared to CB
waves. CB is in the 11 meter band. 850mhz (the longest-wavelength
cellular communication) is in the 0.35 meter band (yep, that's 35
centimeter band). The coax length in a CB installation is shorter than
the wavelength of the transmitted radio signal, the coax length in a
cellular radio is longer than the wavelength of the transmitted radio
signal. The end result is that it is much, much easier to tune the coax
length for ultra-shortwave frequencies, and you can dispense with the
grounded shielding required for good results with CB radio. In addition,
850mhz causes much more impact upon car electronics because this is
close to the frequency that modern computers operate at. This is *NOT*
true of CB radio, which operates on the 11 meter band (that's the 27
megahertz band in case you're wondering). You appear to be holding an
orange and declaring that all fruits are citrus. That is not, however,
the case. The needs of an 850mhz antenna install are far different from
those of a 27mhz antenna install, because the wavelengths (35cm vs. 11
meter) are far different.

> The long and short of it is whatever works for 'you' is fine, but if you
> want to be above board and to avoid expensive 'no warranty' fixes on
> your vehicle, you gotta do it 'their' way.

Please note that a) your "warranty" issues are specific to Canada and do
not apply to the United States where we have consumer protection laws to
prohibit manufacturers from arbitrarily denying warranty coverage for
irrelevant reasons, and b) your installation pointers are applicable to
the 35 centimeter band and do not apply to the 11 meter band, which
requires shielded coax grounded at both ends to a common ground with the
transmitter ground for best results. Please do not confuse the needs of
installing an 850mhz transmitter with the needs of installing a 27mhz
transmitter. Thank you.


-Elron

L. Ron Waddle

Mike Romain wrote:
> L. Ron Waddle wrote:
>> Mike Romain wrote:
>>> A 'ground plane' is a reflective area for amplifying the signal.
>>>
>>> An 'electrical' ground is a power path.
>>>
>>> The 'only' thing they have in common is the word 'ground', nothing else.
>>
>> Well, except for the fact that all mobile antennas other than the "no
>> ground plane" designs use the body as the ground plane and the body
>> also serves as electrical ground. The car body is rather common
>> between the two.
>
> But 'totally' separate!
>
> No ground plane simply means the antenna doesn't need a reflecting
> surface to set it's SWR, 'not' it doesn't need an electrical hookup....

I'm not understanding what you're talking about. You seem to be
confused. SWR is a rating of how much power is reflected from the end of
the antenna back to the transmitter as harmonics instead of radiating to
the airwaves. Reflected power ("standing waves") a) causes the
transmission to sound garbled (since additional wavelengths are
introduced into the amplitude-modulated output), and b) can damage the
input capacitor or output amplifier on the transmitter. The secret to
avoid standing waves is to carefully tune the length of your
transmission chain in order that your power be radiated rather than
reflected back. A poor ground plane (reflecting surface) can certainly
cause SWR's to be high, since this causes power to be reflected back to
the antenna rather than out to the intended destination, but is not by
any means the only cause of high SWR's.

The biggest cause of high SWR's is the fact that typically other parts
of the transmission chain are radiating or are of a length that is
chopping up your waves as they head for the tip of the antenna. Thus if
your coax is not shielded with the shielding grounded properly at both
ends, your coax length should be a half-wave or quarter-wave in length.
For 11 meter band (CB radio), that's 8.25 feet if you want a quarter
wave coax. If the shielding on your coax is not grounded to a hard
ground at both ends, your coax becomes an antenna, and this makes it
harder to adjust your SWR's unless you are quite adept at tuning
combined cable-antenna combinations. That is why the "no ground plane"
setups require a specially tuned cable-antenna combination to work
properly, it isn't necessarily because of lack of a ground plane (I have
seen a regular Firestick work just fine on a 4-wheeler with very little
reflective surface), but, rather, because due to inability to pull a
hard ground on the shielding of the coax on both ends, the coax is now
part of the antenna.

>
>>
>> I'm sorry, but when I want to know about radio electronics I read my
>> ARRL handbook and the handbooks of the antenna and radio
>> manufacturers. When I want to know about cars, I read GM and Ford
>> handbooks. What GM and Ford know about CB (11 meter) radios could fit
>> in the palm of my hand.
>
> I have personally seen many ABS systems crap out from a bad install as
> well as the digital dash and gauges and ignition in one case every time
> the gent transmitted. This is in the fleet of about 200 delivery
> vehicles I serviced.

With a 5 watt CB radio? I'm going to call BS on you. Not that I'm
worried about that, since, like every Jeep TJ I've ever seen, my Jeep TJ
doesn't have ABS.


> I have personally seen GM void the warranty on 'very' new GM vans and
> voided on one Ford van that kept 'blowing' trannies.

Maybe that's legal in Canada. Here in the U.S., they have to prove that
your install caused the problem, or you have a lawsuit against them for
breach of the Magnuson-Moss Warranty Act.

>> So, why did I not run the ground wire to the battery? Simple. Adding
>> an additional ground path to the battery risks fire if the body ground
>> comes loose, because the antenna end of the coax is grounded to the body.
>
> No, you are mistaken. The coax cable is 'physically' isolated from the
> body at the antenna, it does 'not' act as an electrical route for DC power.

The *SHIELDING* of the coax cable is grounded at both ends. (Rolls
eyes). Otherwise the coax cable becomes part of the antenna and must be
carefully tuned in length. You are correct that the center portion is
isolated. Otherwise the antenna wouldn't work, since the whole point of
an antenna is to bounce AM-modulated radio waves off the end of the
thing, and if it's grounded obviously that's not happening! I realize
that American "English" and Canadian "English" are not identical, but we
appear to be speaking foreign tongues to each other here, from what
little understanding is making it out.

If the coax is not properly grounded at both ends (again, I am talking
about the SHIELDING part of the coax, not the CENTER part -- a coax has
*TWO* things in it that carry electricity, doh!), your likely result is
to be high SWR's. And the ground on both ends has to be to a ground
that's at the exact same potential on both ends and said ground has to
be the same ground as the transmitter because the transmitter is
bouncing its waves courtesy of said ground.

> I was transmitting data packets with error correction. It was extremely

On CB radio?! That may be legal in Canuckstan, but CB radio here in the
USA is only allowed to be used for voice transmission.

> obvious when anyone's coax got frayed and 'electrically' grounded to the
> vehicle body by the number of retries in the packets. I would get a
> service call from the mainframe techs.

If your coax ground is not the same as your body ground that certainly
can happen. (The coax ground is the *SHIELDING* ground, once again). You
are then flowing a current through your shielding and inducing
distortion in AC flow in the center conductor (doh, it's called
*induction*, and is the whole thing that makes AC power generation work!).

The best way to make sure this does not happen is to make sure that both
ends of your coax ground, and your CB radio ground, are grounded to a
common ground. Grounding it to the steel body of a Jeep TJ certainly
works to insure that all of these are using a common ground. But if you
add a second ground path for just two parts of the equation (i.e., for
the radio end of the coax and for the radio itself), you do not insure
that you have a common ground, thus can have a ground loop through the
coax shielding with resulting distortion. In particular, if the body
ground wire from the battery to the body goes bad, then everything
*else* grounded to the body is now going to use your radio ground
through the coax shielding. Coax shielding isn't designed to carry a lot
of power.

In non-metallic vehicles such as fiberglass boats, or on vehicles where
the frame cannot be used for grounding such as on aluminum-framed
motorcycles with steel components bolted to the frame (electricity
flowing through an aluminum-steel junction causes corrosion), generally
there is a separate "ground distribution panel" similar to the power
distribution panel. The ground from the battery goes to this "ground
distribution panel" from whence individual ground wires go to the
individual appliances that need power. This is how ground loops are
avoided on these kinds of vehicles. To avoid ground loops, you need
*ONE* wire to the battery ground to a distribution point, then *all*
appliances and applications must connect to that single distribution
point. On my Jeep TJ that single distribution point is the body itself
(or if you want to be picky, the point at which the cable from the
battery connects to the body). Adding additional ground paths is unwise
because, even with a fuse, it adds the possibility of fire if any point
in all possible ground loop paths will not carry enough power to blow
that fuse.

This is Electrical 101. This isn't rocket science. We've known this in
the electrical field ever since the days of ****-and-tube wiring in the
early days of the 20th century where it was discovered the hard way that
a common distribution ground panel was the only way to prevent the
"earth" from causing a fire (early ****-and-tube installations simply
had a ground "bus" that ran to the "earth" on all the plugs). It's
pathetic that anybody would even argue different 100 years after the
issue was settled conclusively.

>> In short, I am both puzzled and baffled by your objections to what
>> every major radio and antenna manufacturer recommends. Perhaps you
>> simply misunderstood what I was posting the first time? Hopefully this
>> clarifies things then.
>
> No, I 'have' to go by the 'Vehicle' manufacturers booklets to avoid 'me'

Somehow I think catching the vehicle on fire by installing it via a
method which violates 100 years of electrical codes might also voide the
warranty (grin!).

> I also worked with RIM (Research In Motion transmitters, think
> blackberry guts) and their isolated antenna specs and power line specs
> were the same as Ericsson's.

Please note that these are *NOT* the same as CB radios. You are talking
about cellular frequencies, which are very short waves compared to CB
waves. CB is in the 11 meter band. 850mhz (the longest-wavelength
cellular communication) is in the 0.35 meter band (yep, that's 35
centimeter band). The coax length in a CB installation is shorter than
the wavelength of the transmitted radio signal, the coax length in a
cellular radio is longer than the wavelength of the transmitted radio
signal. The end result is that it is much, much easier to tune the coax
length for ultra-shortwave frequencies, and you can dispense with the
grounded shielding required for good results with CB radio. In addition,
850mhz causes much more impact upon car electronics because this is
close to the frequency that modern computers operate at. This is *NOT*
true of CB radio, which operates on the 11 meter band (that's the 27
megahertz band in case you're wondering). You appear to be holding an
orange and declaring that all fruits are citrus. That is not, however,
the case. The needs of an 850mhz antenna install are far different from
those of a 27mhz antenna install, because the wavelengths (35cm vs. 11
meter) are far different.

> The long and short of it is whatever works for 'you' is fine, but if you
> want to be above board and to avoid expensive 'no warranty' fixes on
> your vehicle, you gotta do it 'their' way.

Please note that a) your "warranty" issues are specific to Canada and do
not apply to the United States where we have consumer protection laws to
prohibit manufacturers from arbitrarily denying warranty coverage for
irrelevant reasons, and b) your installation pointers are applicable to
the 35 centimeter band and do not apply to the 11 meter band, which
requires shielded coax grounded at both ends to a common ground with the
transmitter ground for best results. Please do not confuse the needs of
installing an 850mhz transmitter with the needs of installing a 27mhz
transmitter. Thank you.


-Elron

twaldron

If the impedances are matched on the antenna, coax and connectors, the
length of the coax is insignificant. Cutting antenna coax to a specific
length to match wavelength in an otherwise matched system is an old
wives tale. Really old.

tw


L. Ron Waddle wrote:
SNIP
> The biggest cause of high SWR's is the fact that typically other parts
> of the transmission chain are radiating or are of a length that is
> chopping up your waves as they head for the tip of the antenna. Thus if
> your coax is not shielded with the shielding grounded properly at both
> ends, your coax length should be a half-wave or quarter-wave in length.
> For 11 meter band (CB radio), that's 8.25 feet if you want a quarter
> wave coax. sNIP