Generator RF Noise

[mustard]

I just installed a Cobra handheld CB with a firestick antenna behind the left driver's window.

I've notice a very large amount of RF noise when running the generator.

Anyone experience this and can tell me how can I eliminate the RF Noise?

[wa8yxm]

YC 1 wrote:
These kinds of issues can be a real challenge. So many variables that one could write a book.

Someone has
ARRL RFI handbook 3rd Edition

[NicodemusY]

What exact model of inverter just died, and what exact model are you replacing it with? Also is this really an inverter/charger?

Confusing 120v paths. Why can't you just plug the fridge into an outlet that works on shore power and use an inverter to run the outlet (and any other 120v things) when off- grid by plugging your shore power into the inverter and turning the converter off?

[wa8yxm]

Non of my radios even know my ONAN (Gas Engine) is running and it actually surprises me they can't hear the fuel pump... Some Generators are noisy I know. What kind of generator are you running.

Now I do hear the alternator from the main engine (Variable pitch whine higher at higher RPM) in the CB. but not in the other radios. all radios "Eat" off the house battery. (a bit over 500 amp; hours of lead acid) both Positive and negative return direct to the house batteries.. I could install an inductor to kill the CB whine but I only hear it when using my earpiece. and since wife died I don't use the earpiece.

Of course my primary mode... It would not matter but on the CB it does

There are several books on RFI (Radio Frequency Interference) you can browse the STORE link at arrl.org Not sure which one is best for this kind of noise.

Possible noise sources Ignition system (Gas) or fuel injector (Diesel)
Fuel pump (Both)
Generator (Brushes)
Converter
Other 120 volt devices inside the RV.

[Gdetrailer]

MOVE the antenna as far away from the generator as possible.

If that doesn't work then you will need to determine of the noise is ignition noise from the gen engine or AVR/brush related noise from the gen head.

Ignition noise is very common on small engines, typically most small engines do not have resister plugs (which suppress ignition noise). Check the plug number to see if it a resistor plug on not, if not then replace the plug with the resistor plug equivalent (you can find plug crossover information by searching the wobbly web).

If not ignition noise then it may be the AVR which uses brushes, worn/dirty brushes can cause excessive RFI but might not be easy or cheap to fix..

[time2roll]

What generator model?

[PNW_Steve]

mustard wrote:
I just installed a Cobra handheld CB with a firestick antenna behind the left driver's window.

I've notice a very large amount of RF noise when running the generator.

Anyone experience this and can tell me how can I eliminate the RF Noise?

I would look at common mode chokes on the generator output.

http://www.dellroy.com/W4EF's-Ham-Radio-Page/Portable_Operation/EU2000i_Filter.htm

[RoyB]

The only RFI I usually get in my OFF_ROAD POPUP setup is coming from my standalone POWER INVERTERs being run off my battery bank. I have a 600WATTS PSW Power Inverter ON all the time running two 120VAC Drop cords with multihead connectors on the end. These two electrical drops are Velcroed to the back of a cabinet top available to use 120VAC items... My Ham radio picks up all kind of RFI noise from this setup...

I have a 1500WATT PSW Power Inverter to use as well but it very seldom turned on... It also will generate a lot of RFI signals. I guess the very expensive Power Inverters like those used in the house UPS UNITS are pretty much RFI free... My House 1000Watt UPS Unit runs all the time with no RFI signals being generated on my Ham radio bands...


Roy's image

My daily camping off-grid routine is to run all my needs off the battery which require me to run my 2KW Generator each morning for three hours starting at 6am during breakfast to get my battery bank back up to there 90% charge state so I can do all of this all over again for the day/night run off the batteries...

It is a challenge sometimes...

Roy Ken

[YC_1]

These kinds of issues can be a real challenge. So many variables that one could write a book.

An improperly installed antenna connector, ground, or taking voltage from a wire or point that is a long way away from your batteries which are the best filters onboard. As suggested, if your generator is a gas right you could have spark plug noise. Good luck.

[MDKMDK]

Turn the CB off when you run the generator, and turn the generator off when you're using the CB.

[MrWizard]

Assuming you mean audio noise you can hear in the CB speaker
What sound does it make
60Hz hum coming from the 120V lines in the wall
Filtered DC hum from the power converter getting in thru the 12v line used to power CB
Or
3600rpm spark plug noise

You don't hear rf interference, RF interference will block / blanket your signal and dampen/reduce what you hear
EMF electromagnetic interference does not have to be in the Radio Frequency spectrum, it just has to be strong enough for circuits to pickup and amplify in the audio output
Our resident HAMS will probably be more helpful

The best way to know what to do to block interference, is to know what the interference noise frequency is

[BFL13]

With an inverter (not a generator) the idea was to use a "chassis ground" to the RV frame, separate from the input DC pos and neg wires from the battery (but battery is itself neg grounded to frame--never mind that!)

Another trick is/was to braid the pos and neg input wiree to the inverter to cancel out their effects.

So--with the generator running 120v in the rig to run the CB radio, what is the actual set-up? Is there an inverter involved? Any DC where you can braid the pos and neg wires? The radio must be DC? Is it grounded to frame?

[Gonzo42]

A Faraday shield could help, but a good ground connection woouldn't hurt, either.

[agesilaus]

I am no electical engineer but I'd think about building a rough Faraday cage out of metal window screen, the fine mesh stuff not hardware cloth.