POWER INVERTERS and HAM RADIO

Discussion in 'Campsite Electronics' started by roybraddy, May 5, 2018.

  1. roybraddy

    roybraddy Well-Known Member

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    I am currently working on updating my BATTERY BANK on the front frame between my front deck and the Propane tanks...

    Since I have things torn apart somewhat was thinking maybe there may be some less frequency radio noise 12VDC POWER INVERTERs being used.

    Since getting the POPUP in 2008 I have been using two Power Inverters both manufactured by AIMS being the 600WATT PSW PWRI60012S and a 1500WATT PSW PWRI150012S...

    The 1500Watt AIMS I have doesn't look like the current unit so I guess they have updated it...

    Both my Power Inverters perform just fine but I really have alot of RADIO NOISE with 1500WAA model. Almost impossible to use my Ham Radio with it running.

    The 600WATT MDL also has some Radio Interference but only the 7Mhz Ham Radio band.

    Separately run the case directly to frame ground with a solid wire helped big time. This is in addition to the normal 12VDC NEGATIVE cable going to frame ground...

    I just occasionally use the 1500W model where I have its output connector going to the other side of the trailer right next to the shore power cable. I can use a 30A to 15A 120V AC ADAPTER cable to connect my trailer to the 1500WATT generator...

    I use the 600watt model most ON all the time. It has two multiple head drop cords plugged into it with one going to the home entertainment area and the other one going to back of a cabinet top near the tent bed end we sleep in. Being ON all the time it becomes a popular place to plug in DC Chargers and items that is nice to stay on no mater what the Shore Power commercial power is doing...

    All of my Ham Radio antennas are around the POPUP trailer with my HF antennas being a LITTLE TARHEEL II Screwdriver mobile antenna and I also have one of the OFF-CENTER wire antennas with the feed being about 25-feet in the air and the legs pulled up into some trees limbs close by. The OFF-SET lengths was 47' on one end and 84' on the other end and this would tune 80M thru 10M. Both HF antennas are used mostly on 75M and 40M freqs. Every now and then I might go up to 20M but those are usually just check in and out and no gab sessions. Used to hang out on 10M all the time too but sort have gone away now as well... Was never a DX'er per say just like to sit up all night shooting the bull sometimes... I got my fill of DX when I was in the Air Force in Germany in 59-63. Our Ham Station was up on a mtn in Germany at a Radar COMMS site. This was when SSB was just starting out and I would get on 20M and say "This is DL4IZ Hello World" and for the next 10 minutes you would be totally jammed by literately hundreds of hams trying to get your attention hehe... What a mess hehe...

    Now days its just a couple of old farts staying up all night yaking on 80M drinking coffee all night...

    I also have 440/2M whips on two locations on the rear of my POPUP for repeater operations.

    I sometimes install a screw-in ground anchor into the ground and run a ground cable over to the trailer frame. It probably helps alittle bit on the lower frequencies.

    If I am into some important WX alert radio nets I usually turn OFF my Power Inverters just to not be interfered by them...

    Just wondering if maybe there is a different brand of Power Inverters some of the Ham Radio Types on here might be using that doesn't have alot of Radio Interference to deal with... I have only played withe AIMS models... AIMS always had the best prices for Pure Sine Wave models.

    Roy Ken
    K9PHT issued in Illinois 1956... Was DL4RO in Germany from 59-63
    [​IMG]
     
    Last edited: May 5, 2018
  2. NMroamer

    NMroamer Active Member

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    Is your inverter a switch mode or transformer type?
    A 330 or 470 uf can type capacitor across the line might help.
     
  3. NMroamer

    NMroamer Active Member

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    Pure sine wave does not mean no noise, switch mode inverters are notoriously noisey.
     
  4. theseus

    theseus Centerville, OH

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    I agree. I've always have found switch mode ones create a lot of noise.

    Roy, I'll be listening for you.

    KE4AGS
     
  5. roybraddy

    roybraddy Well-Known Member

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    I'm sure the Aims are switch modes... The transformer thought does give me a couple of ideas however. I think I know where a transformer can be had that is used for adjusting the line level. The switching mode noise on one side of the transformer would not get transferred down windings on the other side of the transformer perhaps... I know the extension cords running 25-feet away from the 600WATT Inverter seem to act like an antenna...

    I can live with the BRRR's on specific frequencies. Just don't go there... But when it becomes a hash type noise over several Mhz of frequency then that is hard to deal with...

    I wonder if the high dollar Power Inverters do this as well... I'd go a little higher in cost for my always ON 600Watts model if I knew it was going to work ok... Its kinda neat to have 120VAC pure sine wave source all the time for some low wattage items...

    Wonder what kind of Power Inverters are being used in the new cars and trucks now... I don't think they are very high wattage models so its probably just modified sine waves... My neighbor has one on his Tocoma small truck.

    Appreciate the comments

    Roy Ken
     
    Last edited: May 5, 2018
  6. JimmyM

    JimmyM Well-Known Member

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    The EMI/RFI is generated by the hard switching events done by the MOSFETs. They "ring" at turn on and turn off. The switching my occur at 60Hz (transformer type) or at several kilohertz for the switched mode ones. But it isn't the primary switching frequency that causes the noise. It's the ringing that can be several megahertz. There are 2 ways to reduce the ringing. Slowing the switching speed which will generate more heat or snubbers around the FETs. Snubbers are common in better switched mode designs. but omitted on cheaper ones.
    If you're feeling adventurous, you could try quantifying the noise frequency and build snubbers for the FETs in your inverters. But I think you'll only be able to reduce noise. Not eliminate it.
     
  7. roybraddy

    roybraddy Well-Known Member

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    I see the step up/dn transformers for going from 120 to 240 for overseas ops are not all that expensive for 1500WATT use... Why couldn't one wire two of these back to back and put in 120VAC on side and get 120VAC off the other transformer and have two sets of winding between the two sources to get rid of the Radio Interference...

    cheap enough to play with to see what happens perhaps... Think I saw those transformers around $40 each...

    Roy Ken
     
  8. roybraddy

    roybraddy Well-Known Member

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    What would be a good brand of 12VDC Power Inverter in the 600WATT or 1500WATT Pure Sine Wave range with this in mind...

    Roy Ken
     
  9. JimmyM

    JimmyM Well-Known Member

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    I've never investigated this specific feature. But I suspect it would only be on the more expensive units. Specifically anything that advertises low interference.
     

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