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Interference on frequency 765 MHz

VidTron
11-28-2008, 06:04 PM
Hi,

I'm getting pixelation and chopped sound on a couple of channels (FOX,CITY) using the frequency 765 MHz. I have called the cable company and they have replaced my Scientific Atlanta 8300HD for an HD+. Still have the same problem on that frenquency.

The cable guy tested the cable signal, unpluged everthing and powered off all my other devices, still can't figure out the problem.

One thing that helped was to move the cable box around, it was on the right of the TV (RCA D52W17) close to the window, and if we move it to left of the TV, the problem disapears (at least for the short period he checked the diagnostic screen).

Has anyone heard of anything that produces interference at 765 MHz?

Thanks,
VidTron.

videobruce
12-05-2008, 11:04 AM
What TV?
Have you tried another set at the same location?
Sounds as the box is interfering with the sets front end.

Consumer electronics are very 'dirty'. Computers are the worse. They generate alot of 'RF' noise, the type you don't hear.

VidTron
12-17-2008, 10:00 AM
What TV?
Have you tried another set at the same location?
Sounds as the box is interfering with the sets front end.

Consumer electronics are very 'dirty'. Computers are the worse. They generate alot of 'RF' noise, the type you don't hear.

My TV is a RCA projection, model D52W17. I didn't try another set; I don't have another 52" TV around. But I'll keep that in mind.

For the computers, I have a couple of Dells running in the adjacent room, on the other side of the wall. I figured Dells are FCC compliant...

I'd still like to know if anyone knows anything operating a 765 MHz, and if there are any effective shielding techniques I could try out.


Thanks,
VidTron.

videobruce
12-17-2008, 11:18 AM
I figured Dells are FCC compliantYea, ok. That really means alot. :rolleyes:

You don't need another 54" TV to test. Most any TV would do.
Have you tried a different input?
Do you have another outboard tuner you could try? (Always good to have a spare. Get a CECB to keep for a spare or testing)
Have you bypassed the cable box and use the internal tuner?

VidTron
12-17-2008, 02:37 PM
Yea, ok. That really means alot. :rolleyes:

You don't need another 54" TV to test. Most any TV would do.
Have you tried a different input?
Do you have another outboard tuner you could try? (Always good to have a spare. Get a CECB to keep for a spare or testing)
Have you bypassed the cable box and use the internal tuner?

We tried a few things, as you can see from the original post...

The issue is on one digital signal (765 MHz), the cable box is showing the problem when it's set to diagnostic mode. So, I see pixelation on the screen, I hear the audio break, the cable box reports corrected and uncorrected blocks.

Since the cable box was replaced and the problem persisted, it seems clear to me there is a powerful 765 MHz interference causing the reception problems...

Doesn’t look like you have encountered this problem before, but it’s not your fault. Thanks for playing.

VidTron.

JohninTenn
12-17-2008, 03:41 PM
Make SURE the plug is WELL grounded. opper ground rod ot cold water pipe.

BrianO
12-17-2008, 04:25 PM
My TV is a RCA projection, model D52W17. I didn't try another set; I don't have another 52" TV around. But I'll keep that in mind.

For the computers, I have a couple of Dells running in the adjacent room, on the other side of the wall. I figured Dells are FCC compliant...


Your Dells are Class B devices which means they are not allowed to cause interference with any device more than 100 feet away. Since you say they are running on the other side of the wall, one of them could very well be the cause. The next time you have the problem, turn your Dells off to see if one or both of them are the cause.

SJ44
12-17-2008, 10:35 PM
If you are using a UPS, try to bypass it.

videobruce
12-17-2008, 11:03 PM
it seems clear to me there is a powerful 765 MHz interference causing the reception problems Not clear to me. This can be many things other than what you think it is. 765 MHz is OTA channel 63 and CATV channel 119.

You still haven't tried another TV and since you already admitted it was only when it was above one area of your set, that tells me it's your TV!

VidTron
12-20-2008, 01:33 PM
Hi,

Thanks for all the advice, but it's still the same.

- The ground is not an issue.
- The UPS is not an issue.
- The Dells are not an issue.
- The TV is not an issue.
- I also checked the other electronic devices in the adjacent "computer room"

So, I re-organized the AV cabinet and moved the cable box around. I found a better spot, I'll monitor this for a while and see if it stays like this or if the problem returns.

Thanks,
VidTron.

videobruce
12-20-2008, 04:57 PM
The TV is not an issue.Then why did it make a difference when you moved the box?? :confused:

Sounds as the TV is interfering with the box.