Mobile Rigs - Static, interference, and thoughts on these issues...

[Marconi]

SM, I promise to check out the thread HIGH SWR) by M0GVZ using his SWR meter to chart the effectiveness of bonding while he installs his bond connections.

Right off the bat, such a process sounds like it would be a very tedious effort to chart.

I would also think if noise abatement was the goal and one used his radio and his hearing to gauge the noise, as one installs each bond, that would also be tedious to chart.

Then we have the quoted comment I posted above to consider regarding the possible AGC circuit effects. Guess who made that statement?

At the bottom of Bonding "Basics" http://www.k0bg.com/bonding.html

Best I remember years ago, as I drove around with my mobile CB on, the noise would come and go, and sometimes, it was worse than others, and sometimes it was better. We referred to it as Mother Nature is pissed or just Static.

There were areas and some streets around that always seemed noisy. Some of my DX buddies use to hunt for hot spots, the opposite of noise, where the conditions were generally quite as well.

I always got the impression while mobile...that location made a lot of difference and it was not hard to tell the results...if you were in a good area or not.

On the base station I also found that sometimes conditions seemed bad at times and everybody complained...and other times the noise was nice and quite...and that was also easy to tell.

 

[Handy Andy]

I go up maybe 2S? When the stereo is up, it goes up at least 5S as the bass 'hits'. If I turn the radio up to a good song, it goes higher.

I have a poly tank, so the metal sender unit/fuel pump is insulated from everything other than thru the wiring.

Ok, thanks - one thing that always evaded me was the issue of those plastic container tanks. Rust proof yes, but very difficult to work with and once they leak - become a firebomb from the fuel return pressure. It's a set and forget - which helps, but in winter - they can fail - miserably. Not often but upper Midwest winters have not been kind to pavement - the holes left behind have been known to not only damage cars, but swallow them up.

Ok, the reason why I asked was to see how they grounded the unit.

There are several ways they route that pump and sender but it all starts at the seal.

For my own - and this is for my own, I've run the ground wire to the frame and let it carry the current return back to the battery - using a crossmember that held one of the straps. Found this to be a good method of keeping the wiring to the wiring and one single point for ground.

• As you already know, the plastic is not a metal shield - so the noise is going to exist because the plastic provides no shielding - very little noise protection. This is a common trait among those aftermarket and many OEM ones.
• For the ECM/CAN systems - the K0BG article talks about "communication" along the routes to the various sensors. I can attest to the fact that many of these systems are not well thought out. They emit noise throughout the length of the harness and provide little protection in shielding and EMP issues - a simple "polling" noise can be heard of those "proximity detector" stoplight sensors can tell you that - they've gone Bluetooth on many but not all.
• Funny how you work with simpler 2 units of S noise while I have nearly 6 units drowning out even the busy traffic from a local Truck stop I used to hear from my old Scion - which was even simpler than what I have now.
• By noise alone I wish I had that old scion - that is how I learned about Toyotas approach to CAN and RFI was pretty neat - but not these newer ones from our original Big 3. (Toyota used "termination caps" in theirv harness with a grounding "bond" point - like their Rear window defogger and wiper - because their Radio aerial was close by on the rear roof. - that approach worked which lessened the noise they generate or re-radiate.

Some of todays newer stuff though, you can't do it that way - some use a stepper motor that Rr-rr-rrt rrt- it's way up in pressure while others run a simple DC motor vane diaphragm to pressurize the system. That "whir" people can hear then the pressure relay kicks in and it shuts off after cycling the injectors for starting. All timing and they look to the wires to send that data to and from the tank.

You are using the Aftermarket approach, and still have that noise - shoot - I'm running out of ideas to help - except if possible keep the Ground returns short and to the point (shorter run as much as possible) - any open wiring - meaning unconnected - no feature attached - open wire lines can act like mini antennas picking up this field noise- routing, taking - getting it back to re-radiate that noise elsewhere in your harness adding more frustration to your day.

On top of that, to reduce their chances for failure in the field, they place a lot of these newer ECM modules in unshielded plastic boxes that seal out the environment but let that noise drift right out unhindered - even the AM radio audio is so heavily processed - listening to the Game even last year on the old AM band was a chore.

 

[Slowmover]

I agree, Marconi.

Comes back to, if I call, who will hear? Attitude towards what Radio means covers this kind of question.

I’ll stay with horizontal first. Where exhaust pipe is included.

The rest as, “seems obvious”.

But my driveway isn’t the only test (as I mentioned and on which point you expanded), and conditions ever-changing.

To me, too much, isn’t any more difficult than doing fewer. It’s a question of adequate supply, only.

1). If I buy more than I need I have reserves.

2). If I buy with another vehicle or two in mind, I needn’t concern myself right off with $$. I can finish them with another smaller order.

3). The woven braid isn’t cheap. Nor are tinned copper lugs. If I estimate (only) each strap as being 10” with (2) lugs, that sets the order list.

4). 60’ (720-inches) of 3/4” woven is thereby (72) 10” straps. 150-lugs.

A pickup the size of mine (vehicle type) has — I guesstimate after a survey — “need” for 60-straps of varying length.

(72) gives elbow room. (150) lugs may or may not be enough.

But it’s the start that likely gets it done.

$100 for lugs & $70 for (60’) 3/4” woven.

The hydraulic crimper on which 2NC995 started a recent thread was $45

My price ordering online from Grainger was $50+ for fasteners.

$200+ to do one vehicle? Basically.
I have others and so does family. At least (5) where I bet I’ll run out more than once.

Far before I reach the end of that labor will exceed in value all the rest combined.

The real expense is in learning.

I hope this offers context and puts to rest the non-arguments about cash.

The vehicle is as much the system as the other gear, inclusive.

The $500 “Big Radio” I’ve promoted

— Uniden 980 AM/SSB
— RM Italy KL203
— West Mountain Radio ClearSpeaker
— Sotabeam 4-way box
— Apache 3800 Transport Case
— aftermarket mic + coax + ferrites + mount + Ancor Duplex power

Is probably a $750 radio rig after all said & done when RF Bonding + DC Ground upgrades are done.

Too much for a CB/EXPORT? Not really. The idea is to then be able to install any other radio in the future. With ease.

The $500 Radio makes assumptions about vehicle condition.

Only the antenna & mount are left out. $20 or $1,200. An enormous range when we include tuners, etc.

An amp is the wild card.

Thus, where some vehicle components themselves are not up to snuff is where the price doubles.

Repairs not actually part of the Radio Rig budget.

Tell your credit card to quit whining and to get a life.

FWIW, I make buys over time. It’s like Christmas when I come off the road and stop by the UPS office.

The only other expenses I’ve encountered are in dedicating new tool bags (past tools & test equipment I don’t own).

BUCKETBOSS-brand Gladstone-style. Zippered nylon or canvas pouches. Clear fishing tackle cases.
Drawstring canvas for fasteners.

The Workman is worth the price of his tools.

The laborer is worthy of his hire.

(You are paying yourself).

.

 

[Slowmover]

Ok, thanks - one thing that always evaded me was the issue of those plastic container tanks. Rust proof yes, but very difficult to work with and once they leak - become a firebomb from the fuel return pressure. It's a set and forget - which helps, but in winter - they can fail - miserably. Not often but upper Midwest winters have not been kind to pavement - the holes left behind have been known to not only damage cars, but swallow them up.

Ok, the reason why I asked was to see how they grounded the unit.

There are several ways they route that pump and sender but it all starts at the seal.

For my own - and this is for my own, I've run the ground wire to the frame and let it carry the current return back to the battery - using a crossmember that held one of the straps. Found this to be a good method of keeping the wiring to the wiring and one single point for ground.

• As you already know, the plastic is not a metal shield - so the noise is going to exist because the plastic provides no shielding - very little noise protection. This is a common trait among those aftermarket and many OEM ones.
• For the ECM/CAN systems - the K0BG article talks about "communication" along the routes to the various sensors. I can attest to the fact that many of these systems are not well thought out. They emit noise throughout the length of the harness and provide little protection in shielding and EMP issues - a simple "polling" noise can be heard of those "proximity detector" stoplight sensors can tell you that - they've gone Bluetooth on many but not all.
• Funny how you work with simpler 2 units of S noise while I have nearly 6 units drowning out even the busy traffic from a local Truck stop I used to hear from my old Scion - which was even simpler than what I have now.
• By noise alone I wish I had that old scion - that is how I learned about Toyotas approach to CAN and RFI was pretty neat - but not these newer ones from our original Big 3. (Toyota used "termination caps" in theirv harness with a grounding "bond" point - like their Rear window defogger and wiper - because their Radio aerial was close by on the rear roof. - that approach worked which lessened the noise they generate or re-radiate.

Some of todays newer stuff though, you can't do it that way - some use a stepper motor that Rr-rr-rrt rrt- it's way up in pressure while others run a simple DC motor vane diaphragm to pressurize the system. That "whir" people can hear then the pressure relay kicks in and it shuts off after cycling the injectors for starting. All timing and they look to the wires to send that data to and from the tank.

You are using the Aftermarket approach, and still have that noise - shoot - I'm running out of ideas to help - except if possible keep the Ground returns short and to the point (shorter run as much as possible) - any open wiring - meaning unconnected - no feature attached - open wire lines can act like mini antennas picking up this field noise- routing, taking - getting it back to re-radiate that noise elsewhere in your harness adding more frustration to your day.

On top of that, to reduce their chances for failure in the field, they place a lot of these newer ECM modules in unshielded plastic boxes that seal out the environment but let that noise drift right out unhindered - even the AM radio audio is so heavily processed - listening to the Game even last year on the old AM band was a chore.

Some great stuff there, HA. Thx!!

.

 

[Handy Andy]

Then we have the quoted comment I posted above to consider regarding the possible AGC circuit effects. Guess who made that statement?

At the bottom of Bonding "Basics" http://www.k0bg.com/bonding.html

.

Why not just say...

Run the RF gain, if the radio has it, to a level that makes the noise heard versus the signals you wish to hear - acceptable?

Well, in that article, he's saying it...

But in HOW he says it, then I've been fixing the wrong PIN diode section. Yes, IF section - but attenuation is also being applied.

Best to look directly to the article Here_http://www.k0bg.com/signal.html#agc_

AGC LIMITS gain - I would not recommend "shutting it off" as stated in the article - you're looking for a performance disaster then...

SIGH...

 

[Handy Andy]

Do I? Should I? Ok I'll just post this - then.. I'm done!

AGC applies voltage to offset the Gain of the section it's being applied to. So as the signal gets stronger, the issue of room for overhead (capture and envelope) comes into play.

So, the AGC is doing it's job and once the noise begins to drop, AGC is still working to lower the effective gain performance of the receiver - can't avoid that.

RF gain can help, but also too - AGC affects and is affected by, the RF gain because of signal input and the noise it's embedded in. You turn down RF gain, but AGC pops up in effectiveness - which in turn also applies this to ANL and Noise Blanker efficiency.

• For those playing along at home and have a Cobra 29 handy, you can try this with your own...
• 

You can't have one without the other....

Best way to solve this is to work within the system itself - antenna, height, permanent or temporary mounting coax used and routes it takes - even mounting the radio is a spot AWAY from the front dash and it's noise... and if no other way or option, then you open up the radio and reduce a resistor value which then increases the effectiveness of the AGC circuit - aggressively pushing down all the noise and in turn, the received signals also - but then you have a weakened receiver in performance and a poorly sounding station received too - all embedded in that same noise that would still be there whether you tweak AGC or not

 

[2NC995]

There were areas and some streets around that always seemed noisy. Some of my DX buddies use to hunt for hot spots, the opposite of noise, where the conditions were generally quite as well.

I’m at the point where most streets I drive on generate far more noise than my own pickup.

I’m not ready to talk myself out of making an effort to bond my truck - I’ve never done a thorough job and would like to see for myself.

But...it’s not a priority either, especially after installing the DSP speaker.

 

[Slowmover]

Why not just say...

Run the RF gain, if the radio has it, to a level that makes the noise heard versus the signals you wish to hear - acceptable?

Well, in that article, he's saying it...

But in HOW he says it, then I've been fixing the wrong PIN diode section. Yes, IF section - but attenuation is also being applied.

Best to look directly to the article Here_http://www.k0bg.com/signal.html#agc_

AGC LIMITS gain - I would not recommend "shutting it off" as stated in the article - you're looking for a performance disaster then...

SIGH...

“Noise heard versus signals heard”

What I’ve called “audibility” is that level of comfort long-term (hours).

Where the WM SPKR is a great aid.

Not THE fix. But there comes a point where . . . .

.

 

[Slowmover]

I’m at the point where most streets I drive on generate far more noise than my own pickup.

I’m not ready to talk myself out of making an effort to bond my truck - I’ve never done a thorough job and would like to see for myself.

But...it’s not a priority either, especially after installing the DSP speaker.

Last night was typical parking at a truck stop. I have NO idea what the hell some of these yankers have in their trucks. But it’s TERRIBLE.

THEN there’s reefers.

If the received signal is this screwed, what of TX?

Keep this in mind. While underway the info you’re relaying to another fast disappearing in the other direction . . just had got garbled. Lost.

No second chance.

It ain’t just an antenna at issue. If bonding is a form of insurance, I’ll take three, please.

I’ve had “better” rigs in tractors. With more power. Just a few bonds has helped considerably in that with this setup. As “the rest” is better.

IH40E was completely closed the opposite direction at 0400 yesterday. Tanker rollover. Very few alternative routes. Must be taken 10-20 miles or more before the crash site.

I was passed repeatedly by other big trucks and not asked to re-send info by those being warned. Despite passing interference.

Doesn’t always happen that way.

A much “bigger” (better) rig than mine doing the same job just out ahead of me was reaching & receiving no farther so far as I could tell.

The ClearSpeaker was one factor, yes. But I’ve had it years and a quarter-million in operation.

YMMV

.

 

[Marconi]

Andy, I believe that you guys that talk about bonding issues have valid points to make. I don't think it is all BS.

When the discussion talks about noise abatement in a CB receiver, and then the talk gets very complicated and technical, and then it's claimed that the beneficial effects of bonding might not be detectable just by listening to your radio...I have to wonder why.

 

[Slowmover]

Andy, I believe that you guys that talk about bonding issues have valid points to make. I don't think it is all BS.

When the discussion talks about noise abatement in a CB receiver, and then the talk gets very complicated and technical, and then it's claimed that the beneficial effects of bonding might not be detectable just by listening to your radio...I have to wonder why.

As half the answer is lousy audio quality in the first place.

An external speaker with DSP somewhere between radio and speaker-cone tunes up the ears.

Ferrites, bonding and the rest aren’t nearly as efficacious (Mobile).

(Somewhere, perhaps on this site, is the comment that with RG59 you have noise that Heliax better attenuates, but now you can make out the words not earlier heard).

What is signal, and what is noise? (where signal contains distant environmental influences, and noise is much to do with the vehicle constantly changing capacitance while in movement).

.

 

[Handy Andy]

Andy, I believe that you guys that talk about bonding issues have valid points to make. I don't think it is all BS.

When the discussion talks about noise abatement in a CB receiver, and then the talk gets very complicated and technical, and then it's claimed that the beneficial effects of bonding might not be detectable just by listening to your radio...I have to wonder why.

Well, not to wind up in another mess...but I can help in just promoting the very things talked about with "common mode currents" and the like.

One aspect I've found to help with hash and whine noises - when all other avenues have been tried and room to improve them is limited, many times I've heard and suggested, and I still do use on my own equipment; is to use a common point ground for the radio equipment. You still have the power lines, but when it comes to the simplicity - the positive power arrives in the raw and its' filtered at the point of entry (radios power choke) but there is the issue of noise in the ground plane areas of that radio. They do something quite interesting - it's with Real estate of the ground foil. They use a capacitor (1000uF or so) on the main ground and the power feed at the power choke. The closer the two are, the better the noise ripple rejection and noise reduction.

I don't know how far you get into the radio shielding, but in older days they used to make considerable efforts in designing shield plates to be applied to the more sensitive areas of the board for reception problems that say a noisy backplane, or large ground plane of the radios own, and even it's speaker and case panels - can - by proximity alone - induce noise and hash by RFI currents mixing in with and adding to the very signal you are trying to parse out.

Not too many radios still do that...

Even the old Cobra 25 Uniden PC66/68 still do, but on the component side...
This...

This circuit is the last IF stage but note the construction...
It's a POSITIVE feedback design...

You can find it here...
​

They do this to keep the amp stage stable and shielded from itself - keeping it from amplifying (into self-oscillation of a separate resonate frequency derived by the coupling between the two transistors) it's own IF carrier signal it processes - it designed to amplify and process for the Audio envelope .

Now what does this have to do with Bonding?

Well in learning why they use shield plates in radios - it makes sense to keep the device that generates, as well as places that have EXTREME amplification for reception including all the noise, surrounded by and encased with some form of shielding - else any thing that sticks out of it, will act like an antenna and radiate, and receive - noise from the external world

This includes long ground wire runs, the RF current may not "stick to it" but the audio effects of the noisy environment it is used in - can. Plus the effects of inductive and capacitive dressing of leads - harnesses and their proximity to noise sources like ignition systems - crossing over at a 90 degree angle perpendicular - will induce the pulse noises into the lines crossing over that section.

So in light of the above, there is also another interesting effect that even RCI uses to lessen the noise that whines, eddy currents and potential differences even between the rear panel and the ground plane itself used for the main PCB...Common point sourcing...and grounding

Note the proximity of the power choke and the main filter caps located in and around the area...

The larger Ground Traces source to and originate from one point by that power choke..

It's kinda like a spiders web, octopus tentacles, or even an Amoeba - all spreading out from a single point of entry and all the tied braches - having some considerable depth and breadth of copper foil in which to pull and add power to and from - all tie into a pretty much a single point.

Every radio does this - and as they get tinier and tinier - the layouts are more and more difficult to keep cohesive in single point grounding without pinch points and jumpers - the more jumpers - aka wire in harness stuff, you get them to appear as noise sources. So the harder you work on making the ground and power supply feeds homogenous - the better the noise reduction can be and less likely to generate an oscillator from your amplifier.

The vehicle can only do so much in following such sage advice, but if we can provide a common point ground without long wire runs to get there - we can contain the noise and it's currents into a surface and not form a point of entry for that noise to get back into the receiver as an out of phase current or a noisy ground plane image caused by the RFI and static not necessarily at the RF level, but even at audio sound level - Static - inducted into the panels of the vehicle and then transferred to every other part of it - including our radio.

 

[Handy Andy]

Now, here's the answer to the 2nd part of your question...

When the discussion talks about noise abatement in a CB receiver, and then the talk gets very complicated and technical, and then it's claimed that the beneficial effects of bonding might not be detectable just by listening to your radio...I have to wonder why.

It's not a real answer, but it is worth mentioning...

The K0BG site mentions the AGC and leaves us kinda confused on the - "Well I did all this to get rid of the noise, but now the radio doesn't seem to really "reduce" noise all that much..."

The answer to that is, - the radios ability to receive - dynamically - stations that may have signal propagation effects occurring while the signal from that station is arriving and being processed in your receiver.

Such things as reflection - multipath arrival of a signal from the source.

It generates an interference pattern both in reflection off of objects, thru the environment and also arriving to the antenna, and also can ride along within the signal path, it's noise radiated close to the reflective area bouncing the original signal towards you - in AM, you don't truly hear the effect, but you do get noise.

So you have to understand that the noise you are hearing be it local within the vehicle, or external outside being picked up b y the antenna - the dynamics of the reception and the signal strength of everything in proximity to the antenna and the radios' ability to properly amplify and discern a specific frequency and or station you want to listen to on the frequency - is more of the concern. If the noise still covers it up - then you have more work to do - get back to reducing the noise floor of your station.

In regards to the interference pattern and wave cancellation and reinforcement - the "flutter" itself is why we have AGC - it is so the reception of a signal can be made consistent in amplitude or capture in bandwidth of frequency (as in FM modes and SSB) so you can hear the intelligence on it.

So when it comes to the ability of the receiver to handle this widely varying signal, amplitude and in the noisy environment it is being put in to receive that signal - you need the receiver to be able to not only "open it's ears" to get that signal - but as that signal and all the noise in it's environment arrives to the receiver, to keep it from "crashing into your cranium" - uncontrollable volume, amplitude and in some instances can even damage the receivers' circuitry from the excessive amplification.

So the makers use a principle of feedback - to control the gain using the signal strength received, detected and can measure it as a source of power for, applying it to SPECIFIC sections of a receiver to control the gain and handle the dynamically changing conditions of the environment you are operating - receiving signals in.

For a Cobra 29 - your CB radio will vary​

Ok, note the above, for it's a CONFIRMATION as well as a CLARIFICATION on how we should perceive AGC and the noise level we don't seem to be taming - may just simply be the effect of the Receiver enjoying, employing the effort it was designed with and now AMPLIFIES the noise level present - what you do not perceive is this effort of the noise - seeming to be the same, may now simply be a remnant of the noise captured originally mixing in and COMPRESSED into the audio and RF signal envelope captured by the receiver.

Note AGC is a simple voltage divider used as a summation - which the result is then applied to both an IF amp to offset the gain across an Emitter Resistor - and the RF Gain as an amplifier to control the PIN diode attenuation of the input signal.

Input signal: Meaning Everything - Noise inclusive.

• On a segue - The RF gain uses the AGC power as a means to control the amount of signal (Noise - et al.) to maintain a relatively consistent level of input. This keeps the RF Amp working as well as offering the ability of the IF section to properly discern and strengthen the signal you wish to hear.
• Failing to keep the input signal within limits - you can damage the receiver let alone experience poor performance and inability to hear stations because of the distortion of excessive input signal strength placed upon the RF amp - and subsequent stages following it.

The clarifying comes into this from the fact that IF signal is controlled by AGC, but not as the overall one solution to this complex problem - for if we simply used IF amp as the means to control the processing - what would happen to the RF amp if it received higher than expected noise and EMF/EMP impulses from a lightning strike nearby - potential damages can result if the system doesn't use some form of attenuation to control and to provide for a means of protection from such events.

• So as clarity, the IF is using AGC to help control signal level in processing.
• AGC is also NEEDED as a means to help the radio receive signals that if not controlled in volume - envelope or it's impulse and noise level the receiver is being used in - can damage the radio.
• You can't have one without the other - in regards to AGC; BOTH IF and PIN attenuation are used.

If you wish to try an experiment - then simply sub in a variable 50K potentiometer on both R31 and R35 - control them separately.

What you can attain with this - is to learn how AGC can work, by turning lower (Reducing) the resistive value of R31 - makes AGC aggressively to push down noise floor, and if you restore R31 back to original - adjust R35 - to make AGC passively open up the receiver to it's full performance potentials - but exercise care in these adjustment ranges - for you can damage the radio.

 

[Cutlass327]

So my thought of running CB ground, stereo amp ground, fuel pump ground, etc all to the batt neg post is actually doing the opposite of my thought? I thought a common ground point to battery, same as common power point at batt pos post, would eliminate ground loops and other noises..

Should I be grounding to the frame??

 

[Slowmover]

So my thought of running CB ground, stereo amp ground, fuel pump ground, etc all to the batt neg post is actually doing the opposite of my thought? I thought a common ground point to battery, same as common power point at batt pos post, would eliminate ground loops and other noises..

Should I be grounding to the frame??

Frame. See W8JI for a discussion.

.