Frequencies and MATV

[DarkHelmet]

I just came from a meeting with some MATV (Master Antenna Television) consultants regarding the MATV network at a hotel close to JIA.

The network is experiencing intermittent problems and I am at my whits end.

Had the brainwave that it could be airport systems interfering and thought I would ask our experts here!

1. The network runs on co-axial cabling and frequencies range from 6MHz-25MHz, then from about 50MHz to about 75MHz, then the TV channels start at 140MHz (VHF) and up to 800MHz (UHF).

I know our radios for Voice comms range from 118MHz - 136MHz (or thereabouts) a bit hectic here to to go to the books and look em up exactly. (that is why I am asking here )

VOR is below 118MHz, at what frequencies do the NDB (is there one present at JIA?) and other radio systems work?

Could some aircraft/airport equipment be present and communicating on same freqs and thus causing interference with the MATV system closeby?

[John Young]

Hello DH,

Had the brainwave that it could be airport systems interfering and thought I would ask our experts here!

Have edited this 'coz was "up the wrong tree". DH - please make sure we all know the eventual cause & solution.

Question - What about the HF Bands used by the 747's over Africa [13 MHz]? Also, the huge antenna station located near JIA?

[DarkHelmet]

shameless bump but I would appreciate any feedback on this guys

John has stated HAM radio things but this site is RIGHT next to JHB International airport, it is the Intercontinental Hotel in the old admin building on the right hand side of the departures/arrivals terminal.

[DieselFan]

Don't know if this is related or coincidence but since about 3 weeks ago, I've developed severe ghosting on my TV. On 5FM I've often of late picked up radio chatter from what sounds like pilots and ground crew as they talk in all the "Alpha Bravo" stuff and "turning left 20 degrees, heading". Hows this possible? Normally in the morns or late at night (maybe thats because I'm at work otherwise??)

Perhaps a big bird just died on my aerial?

PS I stay very close to JIA...

[Griffin]

Hi DH
It could be the radar system. The primary radar operate at (I think) 2700-2900 MHz which is way above your frequency but it is pulsed and transmits at extreamly high power (Many kilo watts) so it could be getting in any where. The SSR transmitts at 1030 MHz and could also be effecting your equipment. These signal could be mixing with other frequencies and the product could land up in your frequency band (eg 1090 and 1030 will give you one product at 60Mhz which is in the middle of one of your bands)

I think you have an "interesting" problem

[Henry6iix]

Why must the Amateur operators always be at the short end of the mic?
I found that 99% of the time the probleme is not with them (us) but poor installations or equipment used to be blaimed.
I was confronted by a buurman stating that i interfere with is TV.
After Sentec came out and found that it was mnet boosting its opentime signal and my station was clean and in spec He was happy.

To the probleme at hand.

First i will look at the neon lamps in the building ,Computer screens ,microwave ovens, intercom systems,and electric fences.

Ndb`s work below 500khz,500-1099 am radio,1.1-30mhz hf transmisions with 27mhz the old CBers(remeber them)29mhz for 4x4`s and boats users,31-49mhz army50-54mhz ham band 55-65mhz army,66-69mhz farmers,70-88mhz commercial users 88-108mhz ons fm radio (94.7 94.2 or 5fm)109-136mhz air band 137-174mhz commercial users 175-200vhf tv,201-260mhz truncking commertial users 261-350mhz vhf tv 351-430mhz our boys in blue and other com users 430-440 hamband (433.000-433.990mhz low power devices, the handi talkies u can buy at cape unionmart or due south)440-470mhz com users 471-520 uhf tv etv and mnet 800-900mhz cellphones 2.2gig transponders in aircraft 2.4-2.5 wireless lans .

Hope the info will help to solve your problemes on there tv`s