Funny Signals

[diapason]

Something I thought interesting and wondered about. *I am presently pointed to the Hotbird Satellites at 13E and can receive all channels perfectly, except those at frequency 11642H 27500 3/4. *The channels carried include Bloomberg UK , Europe and International and , for some strange reason, the signal strength seems to be cutting out momentarily about every 4 seconds or so, thus resulting in a breakup of picture and sound. *Signal strength when it is there looks about 67%.

Can anyone out there come up with an explanation and has anyone experienced the same phenomenon?

I am at Paisley in Scotland but as I can get all other channels I don't think it is anything to do with our northern latitude. *All suggestions gratefully received.

[BGonaSTICK]

Almost certainly interference. Check for DECT phones, local transmitters (emergency services?) or adjacent cables.

DECT phones have a long range, so turn them off and remove handset batteries as a test.

[BilboBoggins]

Hiya diapason,

if the interference is a constant ie:- 4 secs, then my guess would be radar interference. Are you near an RAF base ? or possible a civilian airport, as some scans are around the 4 second mark. Its probably causing some harmonic interference at that frequency.

Just a thought..

Bilbo

(Brazil game has just started !! )

[BGonaSTICK]

Yeah, it could be a number of things, but my guess is a DECT phone, and here’s why:

Digital Advanced Cordless Telephony (DECT) systems operate within the allotted European Radio Frequency Allocation of 1880 - 1900 MHz.

‘Low band’ - Ku band frequencies from 10700 to 11700 MHz use an LNB Local Oscillator frequency of 9750 MHz.
‘High band’ - Ku band frequencies from 11700 to 12700 MHz use an LNB Local Oscillator frequency of 10600 MHz.

From your missing frequency of 11642 MHz you have to subtract the 9750 MHz LO frequency to get the IF, or Intermediate Frequency (this is the frequency of the signal travelling down your coax and into your receiver’s tuner).

The frequency reduction is the main function of the LNB, and the coax is where you will most likely experience interference.

11642 MHz – 9750 MHz = 1892 MHz

After all that, it'll probably turn out to be the dog having a wee on the receiver! :roflmao:

STICK

[diapason]

Thanks for these useful replies. I live within 2 miles of Glasgow Airport so radar could be the culprit. Pointing a video camera towards the airport picks up 4 second crackles on the sound track.

I also live about 200 yards from a new mobile phone transmitting mast so, again that might be the reason for the interrupted signal. But that mast is 180 degrees from where my dish is pointing, so I wonder.

The picture and sound do try to estabish themselves and if you wait long enough, you can get the gist of what's happening. But every other frequency coming from the Hotbird group works fine. The test might be during the night when Glasgow Airport closes down, as Glasgow Airport is not actually in Glasgow but 2.5 miles from Paisley!!

[BGonaSTICK]

If you pointed a video camera at an airport down this way you'd have an Armed Response Unit in your face every 4 seconds!

[fergiz]

You really shouldn't have bought that dish from Delboy and Rodders mate.

[BGonaSTICK]

LOL, Statellite dish bruv?

[diapason]

Thanks for all the replies. Here's another interesting thing. The same frequency of 11642 also produces the same result when I am tuned into the Eurobird and Astra satellites at 28E so it must be something local causing the bother. A bit annoying on 13E as the financial programmes are useful but of no consequnce at all on 28E as it's only a shopping channel and I'm allergic to shopping!

Special thanks to Stick - but I assure you that I would not have anything in my house with any more legs than what I have, so no dog, and whosever Digital Cordless Phone might be causing the trouble it's not mine as I've tried that. However, there are thousands of channels to choose from and it's all great fun.

[BGonaSTICK]

I think it's someone's phone, but nothing you can do about it...

...except swap out your coax for some very high quality double-screened stuff. Worth doing anyway if yours is a few years old or of poor quality.