HDTV Expert - Buy a Plasma TV While You Can – by Ken Werner

[Roger Halstead]

Under ambient light, or available light if you will, I've just never seen a notable improvement of the plasma display over the LED or LCD. As I don't watch TV under laboratory conditions and even controlled lighting is not an option, all of my comparisons have been, real world. I compare that to the extra weight of the display over LED which can be substantial, the extra power required, and I understand plasma ages. I'm also limited to a maximum of 40-42 inch display. I just don't have a larger place to set up a display unless I redid the basement and put the set where the down stairs fire place is located. Of course removing that fireplace might reduce the heating costs a bit, but the house is already so efficient that the payback for a geothermal set up was 50 years or about twice the life of a typical installation.

As to the radio interference generated by plasma displays, that has been well documented and is fairly wide spread. Not all plasma displays generate the Radio Frequency Interference, but many do. Unless you have a communications receiver close by or a scanner you'd never notice it. It typically sounds like a hiss on the receivers. Hence most hams stay away from plasma displays and if you live near a ham and create interference you are responsible for resolving the issue according to the FCC. There are roughly 3/4 of a million hams US wide so the chances of being close to one are fairly high unless you live out in the boonies which I do, sort or. I live on the edge of a rural subdivision and not counting myself there are 5 ham stations within roughly a mile to mile and a quarter from me. I don't hear any plasma displays at present, but there are a couple of really obnoxious network routers though. The best bet if some one really can see a difference and wants a plasma display is to find a dealer who will let you try before you buy. Best Buy did that with me. They basically told me I could try until I was satisfied. I would assume not all stores follow that policy, but we've done it twice now including having the display properly calibrated for color, hue, and saturation where we view rather than being overwhelmed in the store. OTOH I've never noted the local store adjusting the displays into the "bloom mode". Of course a new manager could take over, or directions from above could change things without prior notice. So there are no guarantees that every one will be treated the same..

[Rodolfo]

Thanks Roger for highlighting your concern with plasma’s RFI issue, which, as you said, is “widely spread” (in Ham radio circles I should add).

The following are some excerpts from November 27, 2002 (eHam.net), the W1RFI poster appeared to be savvy enough with the technology as to be invited for presentations and to speak in conferences, may be you know him:

“These types of devices are unintentional emitters under the rules. Unintentional emitters deliberately generate RF energy, but do not intentionally radiate it. Another example of an unintentional emitter is a computer system.

Part 15 of the FCC's rules set limits on unlicensed emitters of RF energy. Unintentional emitters must meet radiated emissions limits above 30 MHz and conducted emissions limits below 30 MHz. That means that on HF, there is no specific limit on the amount of noise this type of device can radiate.

The manufacturer of the device is required to meet the absolute emissions limits. In the case of a device like this TV, the device must be Verified under the FCC Part 15 rules. This simply means that the manufacturer is required to have tested it for compliance and must have those test results available to the FCC, if an FCC agent asks for them.

This is the sole regulatory responsibility of the manufacturer. The Part 15 rules then stipulate that the operator of the unlicensed device must do so in a way that does not cause harmful interference. In most cases, the operator of the device is in our own household -- where we at least have some control -- or in a neighbor's house. Telling a neighbor that a brand-new TV he just bought at the local electronics emporium is being operated in violation of federal law is a conversation I would not want to have to have with my neighbors.

Even worse, the absolute-maximum emissions limits are extremely high, by amateur radio standards. The limits for intentional emitters on HF -- that can operate in the ham bands if they choose -- are 30 uV/m at 30 meters distance from the source. Translate: S9+15 dB to an 80 meter dipole located 100 feet away. The conducted emissions limits result in approximately the same levels, with the typical efficiency of power-line wiring.

By the time these battles get down to individual cases, the battle may be won, but the war is being lost. ARRL may have put in 500 staff hours dealing with the 3.53 MHz wireless modem jacks, ultimately succeeding in helping to persuade the manufacturer to make design changes, then working with AT&T cable to do a system-wide recall, taking care of 90% of the problem. But the potential in the rules is still there for the next noisy computer, the next new technology and the next widespread threat to HF. “

Roger, as you said, not every plasma panel was guilty as charged, and I am not sure that after 10 years some plasma panels may still radiate unintentional RFI (100% of TV reviews do not do such test/verification), but by the above, it appears to me that a plasma owner would not be responsible (by the FCC as you said) for any RFI it may radiate to any other equipment, Ham radio included, otherwise please share a link to such regulation/owner-responsibility.

It seems you made the LCD choice mainly because the panel size needed to be less than 42 inches, which is the domain of LCD, and because your “real world” image comparisons in a lighted room showed LCD better to your eyes (I only go to the space station to compare TVs so plasma looks better), LCD is very bright and fits well lighted environments; brightness is only one element in image quality, but quite frankly, if the image and view angle also satisfies your quality requirements, look no further, although we all know it differs from 100% of LCD/plasma image quality comparisons done since both technologies were invented.

Enjoy your LCD Roger (and your Ham radio).

Best Regards,

Rodolfo La Maestra

[Roger Halstead]

When it comes to part 15 devices including incidental radiators there is a sticker required on every device that states, should the device cause interference the user must cease operation and should they receive interference they are required to put up with it.

There is no specific signal limit if the device causes interference, but there is a limit to how much the device can radiate to pass qualification.
There are so many devices that can cause RFI we don't have room to list them, but it's seldom that the FCC becomes involved and except in a few circumstances most hams just put up with the interference. OTOH there have been cases where the FCC has actually required uses to cease operation of such innocuous devices such as battery chargers. In reality the FCC really doesn't want to get involved, particularly when you have a large number of devices involved.

[Rodolfo]

Roger,

In other words, what you are saying is that plasma is among millions of devices that radiate RFI, and Ham operators are affected by all of those millions of devices, and since you are one Ham operator that is one main reason you dislike plasma (and the other devices), even if the image quality of plasma has been compared to be better than LCD by all reports.

My response about the FCC not holding you responsible to solve the problem was based on your first comment:

Hence most hams stay away from plasma displays and if you live near a ham and create interference you are responsible for resolving the issue according to the FCC.

But then you are saying this on your last post:

..should they receive interference they are required to put up with it

Could you please reconcile your statements?

Best Regards,

Rodolfo La Maestra

[Roger Halstead]

There's really nothing to reconcile. One statement is about plasma creating RFI and the other is about them receiving it. In both cases it is the plasma display that is held responsible. Part 15 devices must cease operation if they are creating RFI and they have no recourse if they are receiving interference according to the sticker on all part 15 devices.

However it's not just ham radio. AM broadcast is likely to hear the hash created by "some" plasma displays.

[Rodolfo]

Roger,

What I asked you to reconcile from your statements is why a plasma owner is still “responsible for resolving the issue of interference” if Ham operators are still “required to put up with it”, like they do with all the other RFI created by many other devices.

I understand a Ham operator may prefer to own LCD to reduce the chances for more RFI, but, if there are devices that a Ham operator can use to clean the interference created by his own plasma or by a neighbor’s plasma, why plasma owners that appreciate a better image quality (than LCD) are still held responsible (in your view) of an RFI issue they cannot resolve, as it happens with many other devices people buy every day, and a Ham operator can from his/her end, regardless of what the labels say?


Best Regards,

Rodolfo La Maestra

[btreth]

Rodolfo,
There is no conflict. Both statements reference the TV set, not the Ham station. Here is the part 15 statement that all TVs (and other devices) have :

FCC Compliance Statement
This device complies with part 15 of the FCC Rules. Operation is subject
to the following two conditions:
1. This device may not cause harmful interference, and
2. This device must accept any interference received, including
interference that may cause undesired operation.

FCC WARNING
This equipment has been tested and found to comply with the limits for a
Class B digital device, pursuant to Part 15 of the FCC Rules. These limits
are designed to provide reasonable protection against harmful
interference in a residential installation.
This equipment generates, uses and can radiate radio frequency energy
and, if not installed and used in accordance with the instructions, may
cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to
radio or television reception, which can be determined by turning the
equipment off and on, the user is encouraged to try to correct the
interference by one or more of the following measures:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and the receiver.
• Connect the equipment into an outlet different from that to which
the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.

Note 1 and 2. That is what Roger is referring too.

In my work we have many sensors including Radars, sensitive receivers, two way voice and packet communication over WIFI and Public service bands, High frequency data links (licensed), and imaging devices. We use them for a computer generated situation awareness display. We are vary aware of RFI. Not only do we have issues with part 15 rules, but we also have FCC station licenses.
We have learned almost all displays have RFI issues, but Plasma and CRT are by far the worse and we avoided them at all cost.

There is also an issue with 24/7 operation in which Plasma does poorly compared to LCD but that is another issue.

Bill T.

[btreth]

To Put it another way:

If you are an owner of a Plasma display and it causes interference to anybody (Hams are most concerned) then if you (the plasma owner and operator) can not eliminate the interference by changing the location, orientation or operation of the set you (the plasma owner and operator) must cease operation of the plasma set.
If the Ham causes interference with the plasma set and he(the Ham operator) is operating within his licensed parameters you (the plasma owner and operator) must accept the interference.

The problem is this becomes an issue between neighbors, and like most such issues even when one is legally correct, you still have to live in the same neighborhood. That is why most Hams will be happy to work with the set owner and operator to find a solution. In area where there are continuous issues with the product (as with ATT Universe devices) then the ARRL will work with the manufacture and FCC to resolve the issue.

Clear as mud?

Bill T.

[Rodolfo]

My point was that if a Ham radio is also considered as another device that radiates interference, why the “have to put with it” does not apply to the radio itself, but apply only to the plasma in the Ham’s operator view? Or a computer, a modem, a router, a wireless phone, or the thousands of other consumer devices?

According to the text of the Part 15 provided “This device may not cause harmful interference”. What is considered “harmful” and to whom? About harmful to a Ham radio that may also cause “harmful” interference to other far away devices? such it happened to my home theater for about 16 years. I had to listen to radio exchanges in the middle of a movie or while listening Beethoven’s 7th, at high volume, so pleasant indeed.

Would I have felt sympathetic about the objections of a Ham operator regarding plasmas at such time? I guess you know the answer.

Also, according to the same text of the Part 15 provided: “If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference”.

“Encouraged to try” is far different than “being held responsible and obligated to stop using a plasma”, what about a Ham operator being “obligated to stop” interfering into a home theater?

In other words, it works both ways, and it appears the FCC rules are, as btreth said, “clear as mud”.

I prefer display devices of better picture quality, and unless is under 42-inches, the only panels that get into my house are hi-end plasmas, so I agree 100% with the author of this article, get a plasma while they last.

Best Regards,

Rodolfo La Maestra

[btreth]

My point was that if a Ham radio is also considered as another device that radiates interference, why the “have to put with it” does not apply to the radio itself, but apply only to the plasma in the Ham’s operator view? Or a computer, a modem, a router, a wireless phone, or the thousands of other consumer devices?

HINT: Part 15 applies to non licensed use. Your TV (and many other devices such as computers, routers, WIFI, etc) comes under part 15. A licensed station such as Ham radio does not. Licensed operation, as an emitter or as a receiver if operated whiten the license parameters have priority.

If the Ham is operating whiten his license, part 15 says if he interferes with you, your set is wrong. You must accept the interference. If you cause him interference you are wrong and must stop. That is the law. Other licensed activities have the same rights.

I used to have an FM receiver that would receive aircraft transmissions when they flew over my house and used their radio. My receiver was part 15 and had to be modified.

Also, according to the same text of the Part 15 provided: “If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference”.

“Encouraged to try” is far different than “being held responsible and obligated to stop using a plasma”, what about a Ham operator being “obligated to stop” interfering into a home theater?

The first two parts are the rule, the last parts are suggestions for working with the requirements.

The word MUST as in Must not interfere and Must accept interference are key. These are legal requirements where encouraged is just a legal suggestion.

Properly designed and operated home theater should not be receiving Ham radio. However older equipment, mostly high end and tube was poorly designed with shielding and filtering. The designers thought it would interfere with "good" sound. Most Hams would work with you to try and eliminate the interference. They want to be a good neighbor.

Bill T.