VK Logger Ham Radio Forum Archive

G'day!

Last year I operated the RD contest from the in-laws QTH, due to the fact they are 400m ASL and in a nice and quiet RF area with very low noise floors on both 80 & 40m. Sometime in the last 6 months new neighbours moved in 2 doors away, and I suspect with them came a Plasma TV. When I re-erected a dipole back in April/May to prepare for the VK Shires contest I soon realised there was an interference all across HF & 6m and could pick it up in spots on 2m & more recently found it in the 70cm band as well which helped me greatly in pinpoint the location of it using a handheld and beam.

I strongly suspect it's a Plasma TV (as they are renowned for causing widespread HF interference I'd say around 200m radius or more) but have not approached the neighbour. Approaching them would be a touchy topic, as I guess they could see me as invading there privacy coming asking questions about if they own a Plasma and can I please come in and just check. They don't have to allow me in at all and could just lie to my face and tell me to bugger off.

Now having said that, I'm considering emailing the ACMA for there opinion on the topic to find out if there are any legal or official grounds on which serious interference issues with these devices can be resolved. The neighbour could simply switch the tv off to start with for a period, that'd be nice, but about a 24 hour contest. A bit much to ask them to turn the TV off for 24 hours... I could offer to loan them another TV... that's a bit inconvenient, but obviously they have to be friendly enough to want to help out..

opinions?

I recently asked the WIA President face to face along with a couple of others at a recent hamfest about the issue of Plasma TVs and noisy power poles and how they hamper the effort to alude more people to the hobby.. the response I got was fairly discouraging...

Cheers,
Dave
VK3LDR

I have come across a faulty small switchmode supply for a set top box.
When connected to the 240v system and set top box (and through it the TV antenna) it produced over s9 broadband noise on the lower HF bands.
If this is the noise source it would be easier to replace than a Plasma TV.

Dougal
VK4EKA

Plasma TV's are proven noise sources. There are a few YouTube videos showing this in action, eg. http://www.youtube.com/watch?v=hTXlLxV_Xwk

In Europe, Plasma TV's have had the lid nailed in their coffin. No more will be produced for Europe - mainly from an excessive power consumption > CO2 > Global warming (if you subscribe to that - but that's another topic HI), but the upside for the amateur radio community is LCD's are generally far quieter from a noise point of view than your average plasma screen.

There was a write-up about the new Euro directive regarding plasma screens on the RSGB website a few months back.

73 - Rob VK2GOM

Well might be worth a friendly knock on the door with the handheld and yagi in two and pin pointing the source. I had a similar problem with a set top box a while ago, don't know the root cause of why the STB was causing noise but it was putting out some RF noise on the 20m band with an annoying tick. That particular STB stopped working and was subsequently binned...

The 20m noise source was binned along with it.. no more noise.
I confess we have an LCD TV, no RF noise. The only noise you pickup from it is with a handheld receiver placed within 10cm of it... the exact same sound as Plasma TV interference... Which from what I've found infact seems to sound a lot like TV picture transmission.

Thanks for the feedback, I'll pursue the matter further with the neighbour in the short term, as the RD contest is coming again very soon! It would be nice to operate from the comfort of the inlaws again..

Cheers,
Dave

Dave, if the neighbors are uncooperative, then you could try a "Noise Canceller".

I have a JPS ANC-4, and they can work very well on a single noise source.
(JPS have since been taken over by Timewave)



http://www.timewave.com/support/ANC-4/anc4.html

The real trick to these devices lies in the noise sense antenna.
If you can borrow one, then give it a go, although they are not hideously expensive to buy new to begin with.

Testing fate i have just purchased a 63" Samsung 3d plasma.
What a shocker for HF QRN.
On 40m ambient noise is about S5, with the plasma on it goes up to 20db over S9
On 20m ambient noise is about S0, with the plasma on it goes up to S9

Removing all cables except the mains which has 2 clip on ferites installed, no difference to RFI

Walking up to the Plasma with the FT817 and a 2" wire antenna, S7 within 100mm from the screen.
On a couple of other lcd TV's in the house, NIL RFI on HF on the 817 close to the screens.

Should have tried it out in the shop.
I have mentioned to the family thet when GK is on the radio "THE PLASMA STAYS OFF"

The only concillation is the picture quality is just spectacular.

Now just to check how far away the interference is detectable for when the neighbours get a Plasma tv

next step is getting radiation specs of ACMA and testing the levels with lab certified EMI recievers.

Any thoughts folks?

You could always see about taking it back and get your money back, telling the shop it is not fit for purpose (quoting to them that it should not, but does cause terrible radio interference), then go for an LCD instead? We have an LCD here and have no problems at all. All my HF noise is another source.

73 - Rob VK2GOM / G0MOH

PS. Samsungs have a bad habit of dying prematurely. A quick Google on Samsung Plasma PSU will pull up all sorts of horror stories. I had a Samsung 50" Plasma here to repair. Got the PSU board going again, but then it turned out the 'Y Main' pixel driver board had died also. Sold for scrap parts at a few days over 2 years old. Not good.

Hi Rob, If only someone had a big LCD screen
i did mention the "better not cause interference to my ham radio" prior to purchase as i spent a while reading all the "fair trading website" stuff

btw that was your old 817 i used as the "sniffer"

the hash is just spewing out of the panel.

the old 46" Aldi LCD is rfi free.

ironically the 63" samsung "locks up" bigtime when i tx 400w (or so) on 20m.
it goes into channel scroll mode and needs to be reset by the mains switch.
good reason that the family leave the room and watch another telly

Hi Lee, I thought your call sounded familiar That 817 would have been handy now I am playing with 10GHz!

The plasma's essentially have high voltage discharge going on, the results of which are visible to make the pixels, so by their very design they are unscreened broadband RFI generators. I don't think there can be such a thing as an RFI-free plasma screen.

Technology will definitely flow down to bigger LCD/LED/OLED screens since as fast as plasmas become banned (like the ban on sales of them in Europe) the manufacturers will have to fill the gap for bigger screens with other technology.

Or how about a projector? There are nice 3D setups for those too and you can have as big a 'screen' as you like.

73 - Rob VK2GOM / G0MOH

I'm going to dig this subject up for discussion again.

Having two kids under 4 years of age means my Samsung plasma TV operates for most of the day, usually from 7am to 10pm daily. Don't ask me about my power bills!!!

40 meters is bearable, except for around 7.145 where the noise is at around S9+, but as I've discovered this weekend, its playing havock for me on 20 meters as my antenna is a little deaf on 20 and the noise from the plasma is making it very difficult to play on 20 with weaker signals.

So, is anyone in the same boat and have you found a solution that is cheap and easy to implement?

Thanks.
Theo.
VK5MTM.

I have a 2006 model NEC plasma, and noise on all HF bands from 160m up. S9+ on 160/80/40 and gradually decreasing higher.

Disconnecting the antenna and all other connections made no difference. Fitted clip on ferrites to the power cable - no difference, so I assume the noise is being radiated by the set itself.

Due to this and inverter aircon noise I've been considering one of the noise cancelling units such as the DX Engineering DXE-NCC-1. It and an MFJ unit are mentioned somewhere else on this forum.

VK3RX wrote:I've been considering one of the noise cancelling units such as the DX Engineering DXE-NCC-1. It and an MFJ unit are mentioned somewhere else on this forum.

Yeah did some research on some of these devices, they look pretty good but pricey too.

Was hoping someone else had found a cheap, easy and/or homebrew fix.

Telleys are pretty cheap ATM probably the best fix would be replace it with an LCD type I suffer no noise generated with my LCD. Any amateur worth his salt should know how to fix the noise problem by making it mysteriously stop working and then go and get a quiet variety. If it cannot be done surreptitiously an axe or similar could accidentally fall against the screen as many times as it takes

Im fairly disappointed that this matter of TV's causing interference and other appliance type interference is not taken more seriously by the WIA and other parties.

Interference like this and that of power poles sparking, would have to be a larger contributor of why there are less and less people on the air waves and taking a greater part in the hobby. It virtually makes continuing with there hobby impossible in some instances.

People spoke up about effects of BPL interference, it would seem this, in a way is similar.

I know of many operators who just wont or cant get on the air because of these problems, and some who have actully given up and sold all their equipment and moved onto a different hobby.
How could somebody RISK buying something like a IC7800 rig for $15,000! and suddenly there neighbour buys a particular TV and that $15,000 rig is rendered useless!

This kind of issue really needs more attention and more pushing by the WIA.

Sometimes, for cases like this, the WIA would have to take a different tack. Let me give you an example.

In the UK, I was part of the CfDS - Campaign for Dark Skies. We campaigned and lobbied government for reductions in un-necessary upward (useless) lighting to keep the skies dark and preserve our starry heritage. It was an uphill struggle. We changed the tack to 'how wasteful on our energy resources' these un-needed lights are, and action started to be taken.

The WIA shouldn't complain about 'These plasma TV's render our hobby useless'. That will fall on deaf ears. Who cares?! They need to show how environment unfriendly pasma TV's are, through their use and excessive power requirements compared to a modern LCD TV, and the nasty chemicals that can be released during their disposal phase. In this day and age with the current agenda the government is pushing, people will listen to that.

The fringe benefit (but the one we were seeking all along) is less interference from pasma TV's.

It worked in Europe. Plasma TV's are now banned from being sold due to them being non-environment friendly in terms of power requirements

73 - Rob VK2GOM / G0MOH

VK2KRR wrote:Im fairly disappointed that this matter of TV's causing interference and other appliance type interference is not taken more seriously by the WIA and other parties.

Interference like this and that of power poles sparking, would have to be a larger contributor of why there are less and less people on the air waves and taking a greater part in the hobby. It virtually makes continuing with there hobby impossible in some instances.

People spoke up about effects of BPL interference, it would seem this, in a way is similar.

I know of many operators who just wont or cant get on the air because of these problems, and some who have actully given up and sold all their equipment and moved onto a different hobby.
How could somebody RISK buying something like a IC7800 rig for $15,000! and suddenly there neighbour buys a particular TV and that $15,000 rig is rendered useless!

This kind of issue really needs more attention and more pushing by the WIA.

Although I am usually not a huge fan of the WIA, I would suggest that this is more or less outside of their jurisdiction. I would suggest that the initials ACMA be substituted for WIA.

Interference issues and EMC licensing pretty much fall into the middle of their lap. Unfortunately with all forms of government in the country so pussy-whipped by, and beholden to, big business then you are unlikely to see the ACMA do anything about it. (Gerry Harvey might get cranky if you banned the import of plasma TV like has been done in parts of the EU.)

The WIA represents all Australian Amateurs and hence if people want one voice they should be members. United we stand, divided we fall.

Do you think that one individual approaching the ACMA will do better than a national voice in the WIA representing its members ?

Of course interference complaints are an issue for the ACMA. The WIA can & does liase with the ACMA for all Amateurs, and these issues DO potentially effect all operators.

Hence the WIA should raise the issue for its members.

Rob, in addition to environmental issues, how about the health effects plasma TVs may cause due to that broadband radiation. Especially imagine small children watching the TV's from 1/2 meter away

Leigh. You imply that the WIA hasn't raised the issue with the ACMA.

How do you know that ?

Have you tried emailing the National Office and/or Peter VK3MV ?

Might be worth a go if you haven't.

73, Roger Harrison VK2ZRH

VK3LDR wrote:G'day!

opinions?

I recently asked the WIA President face to face along with a couple of others at a recent hamfest about the issue of Plasma TVs and noisy power poles and how they hamper the effort to alude more people to the hobby.. the response I got was fairly discouraging...

Cheers,
Dave
VK3LDR

Are you close to any other neighbouts ? If not, I would build a wideband RFI generator and blank out the TV channels, wait to see if the HF RFI disappears, if yes, well they got tired of your RFI and turned off their plasma. God did'nt say RFI for RFI !

Ok, just a left field idea here, so take it for what it is worth.

The WIA claim to represent the Amateur Radio community in Oz, so assuming for a second that this is the case (No, I don't want to start a debate on that issue), wouldn't it be relatively easy to force thri hand?

I mean, if a bunch of concerned licensees, whether they are members or not, were to contact the WIA asking for them to represent the community on this subject, they would be pretty much beholden to do so, wouldn't they?

To do this there are a number of methods via direct email, phone calls, petitions, articles for AR magazines, articles on the WIA news etc.

Now please don't use this idea and thread as an excuse to bag the WIA, you are probably preaching to the choir anyway, but how about some suggestions and ideas on getting the WIA do something towards helping out those who are cursed by these RFI generators in their neighbourhood?