Through a process of elimination, we have discovered the Safety Dave rear vision camera is causing static interference with our CBs (in car and hand held). The installer said to try putting on u15 ferrite voltage spike noise suppressor which didn't make a difference, we moved the monitor, Safety Dave technicians said they didn't know, we installed a borrowed CB and we direct wired CB to battery. Nothing has worked. Any ideas?
-- Edited by slighty2016 on Saturday 14th of January 2023 10:47:45 AM
Ask Safety Dave for the RCN number of his camera (it should be on the camera - if not you may wish to let the ACMA know) - it *should not* be emitting noise at 477MHz.
There are two ways unwanted noise can enter an electronic device; by RF radiation or by conduction via cables, in your case it's a 50/50 bet.
To rule out conduction disconnect everything from the CB except the microphone. Next power the CB from a seperate 12V battery, virtually any 12V battery will do, switch CB on and listen for interference. If it's gone the interference is being conducted into the CB and almost certainly via its 12V power cable.
If, during the above test, the interference is still present then it's being radiated from the camera system ie. the camera is acting as a radio transmitter.
Just reread your post and note you are receiving the interference on a hand-held which is equivalent to the above test and confirms the interference is likely radiated.
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It is likely the wiring to the camera is acting as an antenna. The first thing to do is ensure the ground (chassis) connection at both the camera and its display is as short and well grounded as possible, no paint under ground lugs and that kind of thing. If possible try rerouting the cable, doesn't matter where anywhere will do.
Next buy a few "clamp-on" ferrites, I think Jaycar sell them, put two of these on the camera to display cable close to both camera end and display end winding the cable through them as many turns as possible: NB. There is a possibility this will degrade the video image?
Next, if necessary, connect a 33pF capacitor across the 12V supply to both the camera and the display placing it as close to each item as possible also keep it's legs as short as possible.
That's enough for now - let us know how it goes, good luck :)
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"I beseech you in the bowels of Christ think it possible you may be mistaken"
Oliver Cromwell, 3rd August 1650 - in a letter to the General Assembly of the Kirk of Scotland
We had a very similar situation with a rear vision monitor/camera set up. Not a Safety Dave unit though.
We tried many different solutions, including from UHF experts & VHF radio enthusiasts & the only thing which worked was to unplug the rear vision monitor.
When the cheap Uniden UHF died we replaced it with a unit of better quality made by ICOM.
The ICOM was fitted using all the same cables & we have never had any more interference issues with our UHF, with the same camera & monitor in use.
We have more recently replaced the camera & monitor after using the old one with the ICOM for several years. No problems with the new camera/monitor set up either.
Whilst no electronic expert, I suspect there was an internal problem in the Uniden UHF all along which somehow picked up interference from the monitor. Not sure how all that might work, but changing the UHF & nothing else made the problem go away, never to return.
-- Edited by Cuppa on Saturday 14th of January 2023 02:26:26 PM
Thanks everyone, we have been in contact with the installer of the monitor again and are arranging a new one to be sent out to hopefully solve the problem as it may be the monitor itself causing the problem. Will let you know how we go.
I've learned a bit over the years putting together the self sufficient solar power systems in the two rigs I have built, & was well schooled by knowledgeable folk including a recognised expert in the field of RV electrics. I am reasonably confident in what I know, but that's as far as it goes. What made you think I was an electronic expert. That's your field is it not?
Or was this just a bit of sarcasm for the sake of it?
I'll chime in here... oldish thread but same topic.
My 2020 Ford Ranger has an OEM tyre pressure monitoring system, using 433mhz radio to transmit from the sensors to the receiver somewhere in the vehicle.
I installed a Safety Dave 7" rear vision monitor to use with the existing Safety Dave camera on my van. Cable to camera, not wireless.
After about 20 minutes of driving with the monitor powered up (no camera/van attached as I'm driving to and from work) I get a dash alarm saying fault with tyre pressure sensor, and one or more of the tyre sensors shows a -- rather than the PSI. Eventually they all fail so it's an issue with the receiver.
Disconnect power to the monitor, works fine again. Power up monitor, fails again. I've repeated this test several times, so no doubt that it is interference from the Safety Dave monitor. All cables as supplied by Safety Dave with the monitor.
Had the cable to the monitor tucked under the roof lining, down A pillar on drivers side past the fuse panel and then out to the camera plug at rear of vehicle. Powered from piggy back fuse, neg to chassis near fuse panel (tested connection to chassis with multimeter). Safety Dave support says it could be due to the piggy back fuse (unlikely, but ok).
Moved the lot to the other side of the car (ie passenger side A pillar, cables run down to kick panel on passenger side, back to camera on the passenger side of vehicle). Power now direct from battery, neg to OEM battery earth location.
It took a little longer to fail but it stills fails.
Waiting on a call back from Safety Dave, will update here with any info.
Blimey, that's a familiar sounding instrument - a spectrum analyser! I last used one in the early '90s.
There wouldn't be too many people that could lay their hands on one of those beauties. But yes, it could be interesting to see what the bandwidth of some of these whizz bangs is.
I wonder if Mike Harding has one for his amateur gear?
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Warren
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If you don't get it done today, there's always tomorrow!
