HFU HF Underground
General Category => General Radio Discussion => Topic started by: Looking-Glass on September 07, 2017, 0129 UTC
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Moving house is bad enough but to find two lots of severe interference all over HF at the new residence adds another challenge.
First lot of spurious noise was all over much of HF, using the Tecsun S-2000 the source was found to be the gas heating "Seeley MagIQtouch" LCD control panel in the lounge room which is wired direct into the mains power and thus runs 24 hours per day. Crawling under the house I disconnected it and some form of peace for the time being.
Second comes and goes, with spurs every 8KHz or so from 3MHz through to 18MHz up to 10dB over on the meter. Faint clicking noise in background noted. Runs for around 3 to 8 minutes then vanishes. Source was found, yet again using the faithful Tecsun S-2000. Surprised to find the source was our brand new Samsung "Digital Inverter Technology" refridgerator in the kitchen. Noise was 20dB over near the appliance, turned it off at the wall point and interference was gone.
All this modern technology is emanating interference on HF, I wonder what else we can add to the list? ???
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Our "inverter" technology Panasonic microwave causes RFI, but fortunately only on the 2.4 GHz WiFi band. We have a dual band router, so 5 GHz is unaffected. I assume at least in the case of your fridge the "inverter" part means using an inverter to run the compressor motor?
IIRC the FCC regs have a blanket exemption for appliances, they do not need to adhere to any RFI limits.
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IIRC the FCC regs have a blanket exemption for appliances, they do not need to adhere to any RFI limits.
So I stick my 500W 43m transmitter in the fridge...
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Been on the Samsung web site viewing the refridgerator details (no manual these days with the unit, have to download as PDF) and not much help at all. May have to place a call with the service toll free hotline.
Spurs are strongest on the 7, 8 and 9MHz bands with the needle plus 10dB, something has to be done.
Failing a resolve will just have to turn it off at the wall to pull out weak signal DX, then remember to turn it back on! ::)
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There are noise filters that can be placed inline with the power cord, and you can always place ferrites on the cord. Mfj makes a brute force ac filter but dunno if it will handle fridge startup current. I wonder if you could faraday cage the main board or something.
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If its inverter drive, sometimes the switching transients get into the frame of the fridge and use it as an antenna. AC line filters can be had for around $20 USD on ebay, just search for 'AC line filter'. That will probably be cheaper than going through a parts house. Fortunately on 240VAC, the fridge shouldn't draw more than a few amps. Select the filter with the lowest cutoff frequency you can find. This should help the problem. If more attenuation is needed, you may have to load up the inverter output leads to the motor with ferrites.
Good luck!
+-RH
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Thanks Josh and Redhat, hopefully one of the options will give some form of result... ::)
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I found myself, E-cigs 3rd generation type.
I will point out though they have to be very close to the reciever.
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For septic here, we have a Clearstream septic tank / UV purifier system. Unfortunately, that power supply for the underground UV light purifier spectrum-wide threw hash of over S9 from LF to to the 6M band. So, two .1uF 250VAC CAPīs, one on terminals of the UVīs AC input, and the other on the UVīs DC output. Now, you have to have a portableīs antenna right over that UV power supply to hear that hash. Panasonic appliances are also notorious for spectrum-wise spurs from DC to light. Heavy investment into ferrite chokes helps to a degree. Then, thereīs DSL MODEMīs. Ferrite chokes on every cabling going to and fro that unit. Then, thereīs CFLīs and LEDīs lighting cheap power supplies. Choke them, where ya can. Now, the AC BZZZZZZZZZZZZZZZZZZZZZZZ that comes from the band-aid fixes from the utility power lines? Move your antennas as far as possible away from that, since the power companies will not want to spent one cent of their quarterly bonuses to have to fix those. And I can hear that all the way into the 222MHz band. Grrrrrrrrrrrrrrrrrrrrr.....
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Yesterday I set up the Yaesu FT-2000D base radio in the garage at the back of the house and no noise from the refridgerator.
However, noise still 10dB over with 8KHz spurs on the Tecsun 2000 across HF, set up in the spare bedroom of the house, switched to battery power but no change.
Probably the Chinese made Tecsun lacks the professional integrity of the big Yaesu when it comes to filtering and dealing with noise?
Incidentally, they both use the same wire antenna.
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Some ferrets on the ac line to the fridge might help dampen them waves. I assume the ac line is carrying the rf to the rest of the house wiring.
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Some ferrets on the ac line to the fridge might help dampen them waves. I assume the ac line is carrying the rf to the rest of the house wiring.
Someone call PETA. ;D
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Josh, the Tecsun 2000 is running off batteries and thus not connected to the mains power, also not coming through the FT-2000D in the garage running off mains.
MDK2: PETA? Is that the Australian version of RSPCA (Royal Society of Prevention of Cruelty to Animals) in the States? ;D
In country areas of Australia at local fairs there is a competition about "shoving a ferret down your pants" endurance test... :o
There was a Vietnam war movie some years back with the VC shoving rats down a mans pants in a torture scene, so rats or ferrets?
Samsung telephoned yesterday and said the appliance was "Approved for Australian Standards" under the import regulations, however, a Samsung technician will call in and check the refridgerator some time next week free of charge whilst in this area.
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I prefer People Eating Tasty Animals ;D
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Nice marmot.
https://www.youtube.com/watch?v=zzy_BV3KTqQ
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'Next time we will cut off your johnson!'
+-RH
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LookingGlass: PETA is a pro-animal rights organisation here in the US. They're a little on the extreme side for a lot of people.
Our version of the RSPCA would be the ASPCA.
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We just got a new fridge today, a Samsung with... Inverter Technology according to the sticker on the front door, which I did not notice when we ordered it (online, due to the hysteria). I gulped when I saw it, remembering this thread.
So far, I have not noticed any major issues. Fingers crossed.
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We got a new washer recently, nice ultra wide band ( all of MW and 1\2 of shortwave) signal from the motor inverter for about 100 ft. Washing during radio hours is forbidden.
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If you putting out this amount of crap as a pirate station, you would soon be shut down but manufacturers get away with it somehow. >:(
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If you putting out this amount of crap as a pirate station, you would soon be shut down but manufacturers get away with it somehow. >:(
Appliances are exempt from Part 15 regulations per 15.103(d):
§ 15.103 Exempted devices.
The following devices are subject only to the general conditions of operation in §§ 15.5 and 15.29 and are exempt from the specific technical standards and other requirements contained in this part. The operator of the exempted device shall be required to stop operating the device upon a finding by the Commission or its representative that the device is causing harmful interference. Operation shall not resume until the condition causing the harmful interference has been corrected. Although not mandatory, it is strongly recommended that the manufacturer of an exempted device endeavor to have the device meet the specific technical standards in this part.
(a) A digital device utilized exclusively in any transportation vehicle including motor vehicles and aircraft.
(b) A digital device used exclusively as an electronic control or power system utilized by a public utility or in an industrial plant. The term public utility includes equipment only to the extent that it is in a dedicated building or large room owned or leased by the utility and does not extend to equipment installed in a subscriber's facility.
(c) A digital device used exclusively as industrial, commercial, or medical test equipment.
(d) A digital device utilized exclusively in an appliance, e.g., microwave oven, dishwasher, clothes dryer, air conditioner (central or window), etc.
(e) Specialized medical digital devices (generally used at the direction of or under the supervision of a licensed health care practitioner) whether used in a patient's home or a health care facility. Non-specialized medical devices, i.e., devices marketed through retail channels for use by the general public, are not exempted. This exemption also does not apply to digital devices used for record keeping or any purpose not directly connected with medical treatment.
(f) Digital devices that have a power consumption not exceeding 6 nW.
(g) Joystick controllers or similar devices, such as a mouse, used with digital devices but which contain only non-digital circuitry or a simple circuit to convert the signal to the format required (e.g., an integrated circuit for analog to digital conversion) are viewed as passive add-on devices, not themselves directly subject to the technical standards or the equipment authorization requirements.
(h) Digital devices in which both the highest frequency generated and the highest frequency used are less than 1.705 MHz and which do not operate from the AC power lines or contain provisions for operation while connected to the AC power lines. Digital devices that include, or make provision for the use of, battery eliminators, AC adaptors or battery chargers which permit operation while charging or that connect to the AC power lines indirectly, obtaining their power through another device which is connected to the AC power lines, do not fall under this exemption.
(i) Responsible parties should note that equipment containing more than one device is not exempt from the technical standards in this part unless all of the devices in the equipment meet the criteria for exemption. If only one of the included devices qualifies for exemption, the remainder of the equipment must comply with any applicable regulations. If a device performs more than one function and all of those functions do not meet the criteria for exemption, the device does not qualify for inclusion under the exemptions.
https://www.law.cornell.edu/cfr/text/47/15.103
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We got a new washer recently, nice ultra wide band ( all of MW and 1\2 of shortwave) signal from the motor inverter for about 100 ft. Washing during radio hours is forbidden.
That is one of the reasons I still wash and dry with my old clunkers. An occasional wideband click beats a never-ending slew of noise from DC to daylight. I also have a problem with washing clothes in a machine whose innerds look like a ceiling fan motor.
+-RH
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Also wall street might become upset at having to pay a few pennies more per appliance, and none of us want to see that!