CB Radio or PRS
#241
Guest
Posts: n/a
Re: CB Radio or PRS - Update -(long & semi OT)
Well, never could turn down a Keith's! Even if I do end up buying. ;-)
I can see what you are saying, if done right no issues.
I guess I just see a lot of crappie installs that 'do' interfere with
onboard systems and am used to the 900 mhz stuff.
I also have a big ball of antenna cable stuck in-between the fiberglass
body layers I wouldn't mind getting rid of.
Mike
Howard Eisenhauer wrote:
>
> Mike, I hope I didn't come across the wrong way on this, I have no
> desire to start a flame war over this. You have, IMHO, a well
> deserved reputation on this group for knowing your stuff, but I still
> think you're wrong.
>
> My position on this comes from being an electronics technician
> working in the radio field for somewheres on the upper side of 30
> years. An awful lot of that time has been spent testing &
> troubleshooting antenna & transmission lines on everything from
> microwave relay links to CBs, with a bunch of cell tower & military
> stuff in between. I think by now I'm pretty well grounded in both the
> theory & the practice.
>
> As far as CBs are concerned, if your antenna is properly designed &
> installed then the length of the coax line & whether or not the coax
> is coiled up is immaterial to the operation of the system. If there's
> a problem with the installation then you may well have problems with
> the coax radiating the reflected power that was supposed to go out the
> antenna. You may also experience the signal trying to get to ground
> through you power cabling instead of the coax shield. In this case
> you may well have interferance problems inside the vehicle & changing
> the length of the coax may affect your SWR meter's reading, but
> changing the length to make the meter read "right" is really only
> covering up the problem. The best way to check the SWR is with the
> meter inserted into the line right at the antenna, unfortunately the
> way most antennas are built makes this difficult. To get the real
> picture of whats happening from the radio end of the line requires an
> antenna line analyzer ($$$- google "Anritsu Sitemaster" for one model,
> did I mention "$$$"?).
>
> I saw what you said about the problems you were having with your fleet
> vehicles & the data systems, I've seen it too. When the digital
> "TDMA" vehicle mount cell phones came out, we really had to crack down
> on the installers to get the VSWR down as far as possible, otherwise
> the bit error rate went crazy. We also made them trim the coax to
> "just long enough" in order to eliminate the loss from the extra
> length, which admittedly is a lot worse @ 850 Mhz than 27 ;>.
>
> If your SWR is high & you can't do anything about the antenna then you
> can reduce to problems inside the vehicle by (gasp) looping the coax a
> few times at the antenna to form an rf choke, this prevents the
> reflected signal from travelling back down the outside of the coax.
> Another trick that works is to get one of those ferrite sleeves that
> you see showing up on power & telephone cables these days. Stick it
> over the coax at the base of the antenna & it'll do the same thing as
> the loops. Running the power leads through one of these things
> wouldn't hurt either.
>
> Tell ya what- next time you're in Halifax drop me a note, I'll get
> some test equipment togeather & I'll try to show to prove to you in
> person what I'm saying is right. If I'm wrong I'll buy you a 24, If
> I'm right you do the buying, How's that?
>
> -Howard.
>
> p.s.- I drink Keith's :).
>
> On Tue, 13 Apr 2004 10:10:35 -0400, Mike Romain <romainm@sympatico.ca>
> wrote:
>
> >You are mistaken.
> >
> >The coil can act as a pickup for noise and it can put out RF.
> >
> >You should really read the TSB out on how to install a transmitter into
> >a new modern vehicle or you will void your vehicle warranty.
> >
> >The antenna cable can and will interfere with the vehicle's onboard
> >electronics. It 'Will' cut out anti-lock brakes. It 'will' cut out a
> >Jeep automatic tranny module so every time you key up you go into
> >neutral. It also will interfere with the fuel injectors.
> >
> >GM, Chrysler and all the rest have booklets out now on how to properly
> >wire a transmitter in order to avoid voiding the vehicle warranty.
> >
> >GM insists on minimum 10 ga. power and ground run right to the battery
> >and double fused there on the opposite side of the vehicle from the
> >wiring harness. The antenna must run on the opposite side from the
> >harness too.
> >
> >So for the power lines, to have a CB on the center or passenger side of
> >a GM van, the wires have to run up the passenger side fender to the
> >front of the vehicle, across the front of the radiator supports and back
> >to the battery. If you run them across the firewall, you void the
> >warranty for the vehicle's electronics, all of them.
> >
> >Mike
> >86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >88 Cherokee 235 BFG AT's
> >
> >Howard Eisenhauer wrote:
> >>
> >> TW, another old wive's tale about the coiled coax thing. If
> >> everything is working the way it should all the signal travels through
> >> the coax between the center conductor & the inside of the braid, not
> >> along the outside where coiling it would have any effect. Coiling it,
> >> tying it up or crocheting it for that matter will not make any
> >> differencet :). There are actually some situations where coiling it
> >> up would make a system work better, but you won't run into them in a
> >> jeep using a commercially available antenna.
> >>
> >> Howard.
> >>
> >> On Mon, 12 Apr 2004 14:40:20 GMT, twaldron
> >> <thomas@OBVIOUSrubicons.com> wrote:
> >>
> >> >The rule of thumb is to be 3 ft. from any other antennas. Shortening
> >> >your coax run in your TJ is not going to help your transmit range. Just
> >> >make sure you don't leave a coil of coax somewhere.
> >> >
> >> >TW wrote:
> >> >
> >> >> I went out and bought an AM CB radio (Uniden Pro 510XL). Now the weekend
> >> >> will be spent installing it.
> >> >>
> >> >> I was thinking how would it look if I could somehow install the CB antenna
> >> >> on the exact opposite side of the radio antenna (same height and spot). My
> >> >> radio antenna is on the right side of the TJ, CB antenna on the left side
> >> >> would ensure coax is shortest and the antenna would be somewhat in the
> >> >> middle of the truck (though to one side). Any ideas or photos of such an
> >> >> install?
> >> >>
> >> >> Thanks for all the help guys. Its much appreciated.
I can see what you are saying, if done right no issues.
I guess I just see a lot of crappie installs that 'do' interfere with
onboard systems and am used to the 900 mhz stuff.
I also have a big ball of antenna cable stuck in-between the fiberglass
body layers I wouldn't mind getting rid of.
Mike
Howard Eisenhauer wrote:
>
> Mike, I hope I didn't come across the wrong way on this, I have no
> desire to start a flame war over this. You have, IMHO, a well
> deserved reputation on this group for knowing your stuff, but I still
> think you're wrong.
>
> My position on this comes from being an electronics technician
> working in the radio field for somewheres on the upper side of 30
> years. An awful lot of that time has been spent testing &
> troubleshooting antenna & transmission lines on everything from
> microwave relay links to CBs, with a bunch of cell tower & military
> stuff in between. I think by now I'm pretty well grounded in both the
> theory & the practice.
>
> As far as CBs are concerned, if your antenna is properly designed &
> installed then the length of the coax line & whether or not the coax
> is coiled up is immaterial to the operation of the system. If there's
> a problem with the installation then you may well have problems with
> the coax radiating the reflected power that was supposed to go out the
> antenna. You may also experience the signal trying to get to ground
> through you power cabling instead of the coax shield. In this case
> you may well have interferance problems inside the vehicle & changing
> the length of the coax may affect your SWR meter's reading, but
> changing the length to make the meter read "right" is really only
> covering up the problem. The best way to check the SWR is with the
> meter inserted into the line right at the antenna, unfortunately the
> way most antennas are built makes this difficult. To get the real
> picture of whats happening from the radio end of the line requires an
> antenna line analyzer ($$$- google "Anritsu Sitemaster" for one model,
> did I mention "$$$"?).
>
> I saw what you said about the problems you were having with your fleet
> vehicles & the data systems, I've seen it too. When the digital
> "TDMA" vehicle mount cell phones came out, we really had to crack down
> on the installers to get the VSWR down as far as possible, otherwise
> the bit error rate went crazy. We also made them trim the coax to
> "just long enough" in order to eliminate the loss from the extra
> length, which admittedly is a lot worse @ 850 Mhz than 27 ;>.
>
> If your SWR is high & you can't do anything about the antenna then you
> can reduce to problems inside the vehicle by (gasp) looping the coax a
> few times at the antenna to form an rf choke, this prevents the
> reflected signal from travelling back down the outside of the coax.
> Another trick that works is to get one of those ferrite sleeves that
> you see showing up on power & telephone cables these days. Stick it
> over the coax at the base of the antenna & it'll do the same thing as
> the loops. Running the power leads through one of these things
> wouldn't hurt either.
>
> Tell ya what- next time you're in Halifax drop me a note, I'll get
> some test equipment togeather & I'll try to show to prove to you in
> person what I'm saying is right. If I'm wrong I'll buy you a 24, If
> I'm right you do the buying, How's that?
>
> -Howard.
>
> p.s.- I drink Keith's :).
>
> On Tue, 13 Apr 2004 10:10:35 -0400, Mike Romain <romainm@sympatico.ca>
> wrote:
>
> >You are mistaken.
> >
> >The coil can act as a pickup for noise and it can put out RF.
> >
> >You should really read the TSB out on how to install a transmitter into
> >a new modern vehicle or you will void your vehicle warranty.
> >
> >The antenna cable can and will interfere with the vehicle's onboard
> >electronics. It 'Will' cut out anti-lock brakes. It 'will' cut out a
> >Jeep automatic tranny module so every time you key up you go into
> >neutral. It also will interfere with the fuel injectors.
> >
> >GM, Chrysler and all the rest have booklets out now on how to properly
> >wire a transmitter in order to avoid voiding the vehicle warranty.
> >
> >GM insists on minimum 10 ga. power and ground run right to the battery
> >and double fused there on the opposite side of the vehicle from the
> >wiring harness. The antenna must run on the opposite side from the
> >harness too.
> >
> >So for the power lines, to have a CB on the center or passenger side of
> >a GM van, the wires have to run up the passenger side fender to the
> >front of the vehicle, across the front of the radiator supports and back
> >to the battery. If you run them across the firewall, you void the
> >warranty for the vehicle's electronics, all of them.
> >
> >Mike
> >86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >88 Cherokee 235 BFG AT's
> >
> >Howard Eisenhauer wrote:
> >>
> >> TW, another old wive's tale about the coiled coax thing. If
> >> everything is working the way it should all the signal travels through
> >> the coax between the center conductor & the inside of the braid, not
> >> along the outside where coiling it would have any effect. Coiling it,
> >> tying it up or crocheting it for that matter will not make any
> >> differencet :). There are actually some situations where coiling it
> >> up would make a system work better, but you won't run into them in a
> >> jeep using a commercially available antenna.
> >>
> >> Howard.
> >>
> >> On Mon, 12 Apr 2004 14:40:20 GMT, twaldron
> >> <thomas@OBVIOUSrubicons.com> wrote:
> >>
> >> >The rule of thumb is to be 3 ft. from any other antennas. Shortening
> >> >your coax run in your TJ is not going to help your transmit range. Just
> >> >make sure you don't leave a coil of coax somewhere.
> >> >
> >> >TW wrote:
> >> >
> >> >> I went out and bought an AM CB radio (Uniden Pro 510XL). Now the weekend
> >> >> will be spent installing it.
> >> >>
> >> >> I was thinking how would it look if I could somehow install the CB antenna
> >> >> on the exact opposite side of the radio antenna (same height and spot). My
> >> >> radio antenna is on the right side of the TJ, CB antenna on the left side
> >> >> would ensure coax is shortest and the antenna would be somewhat in the
> >> >> middle of the truck (though to one side). Any ideas or photos of such an
> >> >> install?
> >> >>
> >> >> Thanks for all the help guys. Its much appreciated.
#242
Guest
Posts: n/a
Re: CB Radio or PRS - Update
Are you sending data over CB, or are you saying that 18' cables is magic for all
cable runs, no matter what frequency band?
alan
Mike Romain wrote:
> That is one person's opinion Jerry and I don't know that person from a
> hole in the ground.
>
> Though I did notice the reception seemed better at 12' than 18' and that
> having a cable 'not' in one of those multiples really messes up data
> packets. Transmitter makers like Ericsson also call for the 12' or 18'
> lines and warn not to coil them which can 'short' the RF out.
cable runs, no matter what frequency band?
alan
Mike Romain wrote:
> That is one person's opinion Jerry and I don't know that person from a
> hole in the ground.
>
> Though I did notice the reception seemed better at 12' than 18' and that
> having a cable 'not' in one of those multiples really messes up data
> packets. Transmitter makers like Ericsson also call for the 12' or 18'
> lines and warn not to coil them which can 'short' the RF out.
#243
Guest
Posts: n/a
Re: CB Radio or PRS - Update
Are you sending data over CB, or are you saying that 18' cables is magic for all
cable runs, no matter what frequency band?
alan
Mike Romain wrote:
> That is one person's opinion Jerry and I don't know that person from a
> hole in the ground.
>
> Though I did notice the reception seemed better at 12' than 18' and that
> having a cable 'not' in one of those multiples really messes up data
> packets. Transmitter makers like Ericsson also call for the 12' or 18'
> lines and warn not to coil them which can 'short' the RF out.
cable runs, no matter what frequency band?
alan
Mike Romain wrote:
> That is one person's opinion Jerry and I don't know that person from a
> hole in the ground.
>
> Though I did notice the reception seemed better at 12' than 18' and that
> having a cable 'not' in one of those multiples really messes up data
> packets. Transmitter makers like Ericsson also call for the 12' or 18'
> lines and warn not to coil them which can 'short' the RF out.
#244
Guest
Posts: n/a
Re: CB Radio or PRS - Update
Are you sending data over CB, or are you saying that 18' cables is magic for all
cable runs, no matter what frequency band?
alan
Mike Romain wrote:
> That is one person's opinion Jerry and I don't know that person from a
> hole in the ground.
>
> Though I did notice the reception seemed better at 12' than 18' and that
> having a cable 'not' in one of those multiples really messes up data
> packets. Transmitter makers like Ericsson also call for the 12' or 18'
> lines and warn not to coil them which can 'short' the RF out.
cable runs, no matter what frequency band?
alan
Mike Romain wrote:
> That is one person's opinion Jerry and I don't know that person from a
> hole in the ground.
>
> Though I did notice the reception seemed better at 12' than 18' and that
> having a cable 'not' in one of those multiples really messes up data
> packets. Transmitter makers like Ericsson also call for the 12' or 18'
> lines and warn not to coil them which can 'short' the RF out.
#245
Guest
Posts: n/a
Re: CB Radio or PRS - Update
Are you sending data over CB, or are you saying that 18' cables is magic for all
cable runs, no matter what frequency band?
alan
Mike Romain wrote:
> That is one person's opinion Jerry and I don't know that person from a
> hole in the ground.
>
> Though I did notice the reception seemed better at 12' than 18' and that
> having a cable 'not' in one of those multiples really messes up data
> packets. Transmitter makers like Ericsson also call for the 12' or 18'
> lines and warn not to coil them which can 'short' the RF out.
cable runs, no matter what frequency band?
alan
Mike Romain wrote:
> That is one person's opinion Jerry and I don't know that person from a
> hole in the ground.
>
> Though I did notice the reception seemed better at 12' than 18' and that
> having a cable 'not' in one of those multiples really messes up data
> packets. Transmitter makers like Ericsson also call for the 12' or 18'
> lines and warn not to coil them which can 'short' the RF out.
#246
Guest
Posts: n/a
Re: CB Radio or PRS - Update
I got confused a while ago and have no idea what is 'right' for what...
Mike
Alan wrote:
>
> Are you sending data over CB, or are you saying that 18' cables is magic for all
> cable runs, no matter what frequency band?
>
> alan
>
> Mike Romain wrote:
>
> > That is one person's opinion Jerry and I don't know that person from a
> > hole in the ground.
> >
> > Though I did notice the reception seemed better at 12' than 18' and that
> > having a cable 'not' in one of those multiples really messes up data
> > packets. Transmitter makers like Ericsson also call for the 12' or 18'
> > lines and warn not to coil them which can 'short' the RF out.
Mike
Alan wrote:
>
> Are you sending data over CB, or are you saying that 18' cables is magic for all
> cable runs, no matter what frequency band?
>
> alan
>
> Mike Romain wrote:
>
> > That is one person's opinion Jerry and I don't know that person from a
> > hole in the ground.
> >
> > Though I did notice the reception seemed better at 12' than 18' and that
> > having a cable 'not' in one of those multiples really messes up data
> > packets. Transmitter makers like Ericsson also call for the 12' or 18'
> > lines and warn not to coil them which can 'short' the RF out.
#247
Guest
Posts: n/a
Re: CB Radio or PRS - Update
I got confused a while ago and have no idea what is 'right' for what...
Mike
Alan wrote:
>
> Are you sending data over CB, or are you saying that 18' cables is magic for all
> cable runs, no matter what frequency band?
>
> alan
>
> Mike Romain wrote:
>
> > That is one person's opinion Jerry and I don't know that person from a
> > hole in the ground.
> >
> > Though I did notice the reception seemed better at 12' than 18' and that
> > having a cable 'not' in one of those multiples really messes up data
> > packets. Transmitter makers like Ericsson also call for the 12' or 18'
> > lines and warn not to coil them which can 'short' the RF out.
Mike
Alan wrote:
>
> Are you sending data over CB, or are you saying that 18' cables is magic for all
> cable runs, no matter what frequency band?
>
> alan
>
> Mike Romain wrote:
>
> > That is one person's opinion Jerry and I don't know that person from a
> > hole in the ground.
> >
> > Though I did notice the reception seemed better at 12' than 18' and that
> > having a cable 'not' in one of those multiples really messes up data
> > packets. Transmitter makers like Ericsson also call for the 12' or 18'
> > lines and warn not to coil them which can 'short' the RF out.
#248
Guest
Posts: n/a
Re: CB Radio or PRS - Update
I got confused a while ago and have no idea what is 'right' for what...
Mike
Alan wrote:
>
> Are you sending data over CB, or are you saying that 18' cables is magic for all
> cable runs, no matter what frequency band?
>
> alan
>
> Mike Romain wrote:
>
> > That is one person's opinion Jerry and I don't know that person from a
> > hole in the ground.
> >
> > Though I did notice the reception seemed better at 12' than 18' and that
> > having a cable 'not' in one of those multiples really messes up data
> > packets. Transmitter makers like Ericsson also call for the 12' or 18'
> > lines and warn not to coil them which can 'short' the RF out.
Mike
Alan wrote:
>
> Are you sending data over CB, or are you saying that 18' cables is magic for all
> cable runs, no matter what frequency band?
>
> alan
>
> Mike Romain wrote:
>
> > That is one person's opinion Jerry and I don't know that person from a
> > hole in the ground.
> >
> > Though I did notice the reception seemed better at 12' than 18' and that
> > having a cable 'not' in one of those multiples really messes up data
> > packets. Transmitter makers like Ericsson also call for the 12' or 18'
> > lines and warn not to coil them which can 'short' the RF out.
#249
Guest
Posts: n/a
Re: CB Radio or PRS - Update
I got confused a while ago and have no idea what is 'right' for what...
Mike
Alan wrote:
>
> Are you sending data over CB, or are you saying that 18' cables is magic for all
> cable runs, no matter what frequency band?
>
> alan
>
> Mike Romain wrote:
>
> > That is one person's opinion Jerry and I don't know that person from a
> > hole in the ground.
> >
> > Though I did notice the reception seemed better at 12' than 18' and that
> > having a cable 'not' in one of those multiples really messes up data
> > packets. Transmitter makers like Ericsson also call for the 12' or 18'
> > lines and warn not to coil them which can 'short' the RF out.
Mike
Alan wrote:
>
> Are you sending data over CB, or are you saying that 18' cables is magic for all
> cable runs, no matter what frequency band?
>
> alan
>
> Mike Romain wrote:
>
> > That is one person's opinion Jerry and I don't know that person from a
> > hole in the ground.
> >
> > Though I did notice the reception seemed better at 12' than 18' and that
> > having a cable 'not' in one of those multiples really messes up data
> > packets. Transmitter makers like Ericsson also call for the 12' or 18'
> > lines and warn not to coil them which can 'short' the RF out.
#250
Guest
Posts: n/a
Re: CB Radio or PRS - Update -(long & semi OT)
Yeah, thats the problem for sure. To work properly the ground plane,
i.e. Jeep, should extend 1/4 wavelength away from the antenna base in
all directions.
That would be one whacking big Jeep :>.
Even at that you need a matching system (loading coil) to bring the
impedance to 50 ohms, which will compromise the bandwidth & burn off
some of the signal with resitive losses. There just ain't no free
lunch :(.
I've got a Lil'Wil stuck to the top of my Durango, tuned to something
that isn't too indecent-, ~1.3-1@ ch. 20. Just opening one door
drives it up over 2:1.
It's a small miracle that the things work at all :).
Howard.
On Tue, 13 Apr 2004 16:00:52 -0400, FrankW <fworm@mxznorpak.ca> wrote:
>I concur!
>What you describe is absolutely correct by my experience.
>The real trick is to get the antenna to match the xmtrs' rated load
>Typically 50 ohms unbalanced.
>
>
*Snip*
i.e. Jeep, should extend 1/4 wavelength away from the antenna base in
all directions.
That would be one whacking big Jeep :>.
Even at that you need a matching system (loading coil) to bring the
impedance to 50 ohms, which will compromise the bandwidth & burn off
some of the signal with resitive losses. There just ain't no free
lunch :(.
I've got a Lil'Wil stuck to the top of my Durango, tuned to something
that isn't too indecent-, ~1.3-1@ ch. 20. Just opening one door
drives it up over 2:1.
It's a small miracle that the things work at all :).
Howard.
On Tue, 13 Apr 2004 16:00:52 -0400, FrankW <fworm@mxznorpak.ca> wrote:
>I concur!
>What you describe is absolutely correct by my experience.
>The real trick is to get the antenna to match the xmtrs' rated load
>Typically 50 ohms unbalanced.
>
>
*Snip*