Radio Issues - Noise when pit crew mic keyed
I've been going through as many messages as I can find and might have missed the answer to this.
Trying to narrow down the problems.
Digital Vertex radios (EVX261).
When the pit crew keys their mic, there is a bunch of noise that makes it hard to understand anything.
So I assume the source of the noise is the pit crew radio which is battery operated.
We've tried a few different mic/headset combos.
Ideas?
Had same problem with with several crew guys for the last few events. Went away when all the radio-to-headset cords got replaced. Vendor admitted the quality was questionable.
Ian Macpherson
Savannah, GA
Race prep, support, and engineering.
Have you tried a choke on the cord between the headset and the radio? Suppose it is possible the cord maybe acting as its own receive antenna.
I'm sure you can find some around - but Radio Shack is history. Check with a few HAMs.
If you can't source one; I can look in my bits box and send one.
Cheaper than a new cable -- if it works.
Cheers - Jim
When I used to fly Phantoms, I was called an AVIATOR.
Now I race cars. So, am I now called a PAVIATOR?
Have you tried with just the crew radio and rubber ducky antenna? I've had similar issues with bad headsets and bad cables, but to rule out a bad radio, or something on the car/driver side, you probably want to remove as many variables as possible and work through several iterations such as:Originally Posted by BeerBudgetRacing
Crew radio to Car radio w/o cables and w/ standard antennas
Then install Car radio and driver helmet
Then turn on the car (ignition interference)
Then add crew headset
Then add remote antenna (if you're running that set-up)
"When the pit crew keys their mic, there is a bunch of noise that makes it hard to understand anything."
one of our driver's complained about this at a champcar race. the problem seemed to go away when his wife gave up the radio to go get food. YMMV
LOL.
I don't know if I can tell my crew chief that..
(Actually - she'll make a hand gesture and laugh as hard as I just laughed!)
To clarify (and defend), the noise occurs without speaking.
(Yeah -that might be worse!)
So, in the car I switch to a rubber ducky, then switched back to the installed antenna. No change.
I took the radio off car power and used a battery. No change.
Good checklist - more to work through.
Thanks.
Yeah. Went through that with radio to car adapters. The thing kept keying the radio.
The reality is they are all made in China. But the quality can be different.
It can be random finding what works.
Have not - will try it. I think that is a possibility.
My system has been hit or miss...either I can't hear crew, or crew can't hear me....but sometimes works perfectly. Have tried to replicate problem while not driving, but it always seems to work fine. Have checked every connection, and replaced a few cables as well. Very frustrating considering the price.
Last edited by ejsprint30; 08.04.21 at 1:59 PM.
Does the engine running or not running make a difference. I know this is a very obvious question...
Also I have had cases where the squelch had to be adjusted to a certain level when multiple radios were transmitting to the driver.
YMMV
This is a single crew radio situation.
I want to say we've tried both but I can't say for sure. It seems worse in the pits than on the track - BUT we do more talking in the pits/on grid.
I thought there must be some 'engine or ignition' noise - that's why I went to a battery. But that didn't change.
Should I put shielding on the inside of the engine cover?
The ECU is within a few inches of the helmet harness wire.
But at this stage I'm thinking is not the in-car stuff.
I had an issue where certain frequencies on my analog radio (self-contained battery) picked up noise from the steering-wheel digital display, apparently through the shark-fin antenna that was just in front of the dash hoop. Other frequencies were fine. And it was sort of random which frequencies produced a loud squeal and other noise as soon as the power was on to the display. Made no difference whether the engine was running or not.
Dave Weitzenhof
Have you tried the crew radio with just the radio? No headset? Maybe I missed it....
Is the crew member using the radio keying the mike from the headset or the radio itself?
Peter Olivola
(polivola@gmail.com)
Basic Copper may have the solution. Halfway down the first page.
V/r
Iverson
No.
Headset.
Yeah. Need to pull both radios. Try in their natural form. Then add the crew headset and see....
I have a backplane on the car. Shark antenna kit from Sampson. In the nose - away from all other electronics.
RF01 FC. Antenna in the nose, radio mounted on avionics mounts under the shock cover just above the pedals.
If I understand correctly, backplanes have more to do with transmitting than receiving.
I'm guessing a "ground plane" like a copper plate under the antenna mounted on the car? GOOD. Just a quick check on the car antenna lead - often these can be LOOONG - don't wrap into "spools" and wire tie. Umm not good. Just one man's opinion/experience.
Cheers - Jim
When I used to fly Phantoms, I was called an AVIATOR.
Now I race cars. So, am I now called a PAVIATOR?
I would focus on the crew end not the car end. You said you only hear it when they are transmitting. The receiver in the car would likely hear noise all the time if it was an issue there.
the buttons on the headsets go bad. Definitely eliminate the headset first and try.
Process of elimination
First, eliminate as many variables as possible. Try without the crew headset. Then try with the headset and make sure the crew member has the mic to their lips. It can also be the headset jack into the radio or the cable into the headset.
Going a bit further, I've had this issue with my radios at times. Try changing channels to a higher frequency.
“Racing makes heroin addiction look like a vague wish for something salty.” -Peter Egan
Update:
Since I needed a new helmet for the new year I decided to have the helmet kit professionally installed.
I took it to Sampson and their staff installed it. Nice clean job too.
At the same time I picked up a new headset for my crew chief and had them check my radios.
Result:
Crew to Driver: 95% of the time (pits and track), crew to driver is perfect. Way better. Attribute improvement to the quality headset.
Driver to Crew:
In the pits, it's excellent, but on track with engine at speed I'm told it's all static.
Between sessions at the track I moved the helmet lead away from all other wiring. No change.
So, the next thing might be the car harness, but if I'm in some sort of static noise bubble with my head 18-24in from alternator, plugs and coils, is that going to make a difference? I'm thinking the mic is picking up interference noise or being bombarded by RFI.
I'm going to install a ground wire as suggested here:
https://www.apexspeed.com/forums/sho...l=1#post306743
Or should I be adding shielding somewhere?
Any other thoughts?
Is the microphone seeing airflow from a vent in the helmet?
No. it's a Bell GP3 and it's solid where the mic is.
In my tool kit I have frequency meters a EMF and a higher frequency one. Did want a spectrum analyzer but not much use on a boat.
I would look for noise effecting the system.
Would check the radio system with no accessories, then check car with out radio on. Then keep checking and adding devices and motor running.
Most of the inexpensive meters do not have recording ability but stick meter in front of camera and use to record on track data. Is there an RPM range that this is noticeable at? I would check ignition wires sometimes they break down as all insulation does.
I have ZERO experience with the new fangled digital radios.. HOWEVER.. I do have a bit with the analog kind and my experience tells me that a MAJOR factor in clear communications via radio (of any kind) is BACKGROUND NOISE. My (aging .. analog) radio works GREAT most of the time. But SOME TIMES, my wife stands in a location that has very high background noise when cars are running 'nearby'. And 'nearby' can mean "within eyesight". Even cars over 100 yards away.. if the transmitter/mic is located close to a WALL.. or any other surface that can reflect back the noise to the mic.
One thing to TRY - would be to key the mic while MUTING (to the best you can manage) the mic input (put it in a sock.. pillow... tight fist, etc .. or vacuum chamber if you happen to have one handy. .. or you could CUT THE WIRE to the mic) to guarantee that no "Extraneous NOISE" is causing the issue. On the receiving end you should hear the squelch open.. and NO .. or 'not much' noise.
I have tried .. endlessly.. to get my wife to 'talk softly' (we haven't addressed the 'big stick' part yet) and 'muffle' the mic as much as possible. From my perspective in the car, THAT is the thing that I notice most. The second thing I notice most is that she usually only says something ONCE. By the time she's done saying it.. I can almost always recognize that something has been said.. but not WHAT was said .. some times. Some times.... I'm "pretty busy" when she talks
Anyway.. almost all communication to the car from the pits is subject to ISSUES. I just have to deal with them and hope I get most of the info I really need to finish the race
Steve, FV80
I guess I should add that I AM an electronics engineer and I CAN easily see 'audio overload' being a significant factor in digital radio systems. The artifacts created by the 'digitalization' of voice comms can easily be exacerbated by elevated background noise... which is VERY COMMON at racetracks. Same goes for ELECTRICAL interference..spark plug, coil, digital dash comms, etc.
Steve, FV80
Racing since '73 - FV since '77
Any recommendations? I see a bunch on Amazon from $39 to $400+
I would think I'd want a directional one so I can point it at my test source.
As for RPM range - 5000 to 6800. Under yellow or cool down lap it seems to work better.
I have none to recommend as electronics changes regularly. I think Owon or something like that has reasonable ones.
The ones I got were under 100$.
Typed out some hints but your PM is full
Just got that notice and cleared out a bunch of messages.
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