# Suppression of generator interference

**URL:** <https://boards.straightdope.com/t/suppression-of-generator-interference/263761>\
**Category:** Factual Questions\
**Created:** [September 9, 2004, 11:11am UTC](https://boards.straightdope.com/t/suppression-of-generator-interference/263761 "2004-09-09T11:11:59Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\
**Post date:** [September 18, 2004, 9:14pm UTC](https://boards.straightdope.com/t/suppression-of-generator-interference/263761/21 "2004-09-18T21:14:45Z")

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Have you tried [these guys](http://www.arrl.org/tis/info/rfigen.html)?

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**Author:** ![DougC](https://avatars.discourse-cdn.com/v4/letter/d/7feea3/32.png) [@DougC](https://boards.straightdope.com/u/DougC)\
**Post date:** [September 19, 2004, 1:14pm UTC](https://boards.straightdope.com/t/suppression-of-generator-interference/263761/22 "2004-09-19T13:14:35Z")

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- 
  - 
    - The best material for shielding both RF and magnetic fields is called mu-metal but it is expensive and most of the time it is not neccessary. What I would try is making a shield out of regular 4130 sheet steel first, get the thickest gauge that is convenient to cut with snips and bent by hand, it doesn’t need to be real thick, and then make a partial shield/enclosure of that and connect the shield to the generator’s chassis. Or if you can find any cheap, thin steel mesh or grating, try that–but don’t use aluminum or brass, because you want a metal with a lot of iron in it.

- Another option is to have someone who is a HAM radio/electronics enthusiast bring out an oscilloscope and “hunt down” the source for you. All you know is that your 300Khz radio doesn’t work when the generator is on–you really don’t know what frequency the generator is giving off, and knowing that (as well as the true source) could be a major help in finding a solution.  
~

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**Author:** ![Mort\_Furd](https://avatars.discourse-cdn.com/v4/letter/m/8e8cbc/32.png) [@Mort\_Furd](https://boards.straightdope.com/u/Mort_Furd)\
**Post date:** [September 19, 2004, 2:34pm UTC](https://boards.straightdope.com/t/suppression-of-generator-interference/263761/23 "2004-09-19T14:34:01Z")

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> [@Kymodoce](#):
>
> I have been experimenting today, and I have found the following:
> 
> i) The shorter the antenna cable on box B, the less the effect of the interference.
> 
> (snip)
> 
> iv) This model of generator has an alternator built in to the engine itself. The output is from a micro-processor controlled inverter.

The inverter would be my bet for the source of your troubles. What type of antenna cable are you using? I’m thinking about the old AM radios and SSB and HAM stuff, and it seems to me that a lot of that kind of stuff uses symmetrical antenna cables - two conductors in parallel rather than one shielded like with coax.

If that is the case, you may want to check that your antenna cable is properly installed - balanced connection at both ends, not grounded at all, and cable properly twisted along its length.

If you are using coax, then I would suggest checking that the antenna ground (the braided part of the cable) has a good ground, and that ground on the radio and the generator be tied together. I’m not sure how you do that safely, though. I’m used to working on automobile type situations where you can just ground stuff to the battery and the chassis and not have too many worries about safety - just making sure that all of your ground points actually have good connection.

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