Multi-Link Aerials...what can they recv?

cookie_mnster

Hi there,
not sure if this is the place to get an answer but I used to have NTLs Multi-Link which gave me the Multi-Link signal and RTE/NET2/TV3.....have now moved to SKY and am still getting RTE/NET2/TV3 on the Multi-link aerial.....

now...I'm right on the east coast and was able to get BBC/UTV/CH4 from a regular roof-top aerial.......as the connections are still in place from the Multi-link aerial I was wondering if this was strong enough to pick up the BBC..etc signals?

Thanks

icdg

You would never have recieved RTE, TV3, or TG4 from the MMDS aerial. NTL don't carry them (despite a licence requirement that they carry TV3). The channels carried on the MMDS service are BBC ONE NI, BBC TWO, ITV1, Channel 4, Sky One, Sky News, MTV, and CNBC Europe. This leaves three channel for premium services.

You may have had a UHF aerial installed with the MMDS aerial that enable you to pick up the terrestrial channels.

The MMDS aerial isn't designed to pick up UHF TV - you need a UHF aerial of the correct type for that.

watty

The MMDS aerial is not really an aerial at all. It is an LNB for 2.5GHz (Sky etc is 10.7GHz to 12.6GHz) on a VERY small dish.

Two versions of the LNB exist: One, a box on the back of the "dish" has a 190MHz to 400MHz roughly O/P, this is VHF Band III / Hyperband. Infact US Cable TV, as the old Jerrold boxes are simply US Cable TV boxes.

Any "unscrambled" channels (it varies from site to site) can be recieved by any TV with cable/hyperband tuning and a 12V DC plug top power unit feeding up the cable via a VHF "choke" (10 turns enamel wire about 1/10th inch diameter air core).
It is only illegal to watch "scrambled" MMDS signals as the "clear" ones are just regular TV at 2500MHz intead of 600MHz (UHF).

The newer LNB is cunningly inside the rod that supports the pickup dipole. It has a UHF output to feed either a TV (analog) or the SAGEM Digital Receiver. So its o/p is more like regular LNB, with is 700 to 2100 MHz.

Instead of a "Horn" feeder like satellite, the MMDS uses wire loop inside a plastic moulding on the rod supporting it at the "dish" focus.

Beacause the wavelength is about 1/4 of Satellite the mesh can have 4 times bigger holes.

C Band Satellite, which uses 3m dishes to feed cable head ends in Asia, Africa, S. America and USA is 3.9GHz


Here in Limerick a few months ago the "clear channels" were TV3, Chorus/Bravo/H&L shared channel and CH4. Quality except on the Chorus channel was very poor.

A few years ago in Limerick BBC1, BBC2, UTV, C4, TV3, and Shared Channel all Clear.

Analog MMDS does not use encryption. Again it is a simple US TV cable scrambling. Digital MMDS is in essence the same system as Sky Digital, except a different Encryption scheme and 2.5GHz instead of 11GHz

watty

The MMDS aerial on your house belongs to NTL or Chorus. They rarely take them away when a customer cancels.

If you moved into a house that cancelled Chorus long ago and it is the old type LNB, they are unlikely to come looking for it.

The old type the LNB box unplugs from "dish" via an "N" connector. Wireless LAN uses 2.4GHz, so the 2.5GHZ MMDS dish/diople will work quite well. You can fit a cable to the WiFi card or Airpoint (set to "bridge mode"), and plug in the "N" connector, discarding the old LNB.

Two of them with Chimney "line of Sight" ought to give over 1Km range (connect you and your mate or Office ADSL to home).

Perfectly legal, as long as you give Chorus / NTL back their undamged Dish/LNB if they ask for it.

spongebob

you are saying in effect that much of the infrastructure required for Mesh radio technology in the 2.4Ghz band is kinda sitting all around rural Ireland.... mmmmmmmmm...pre-installed and all bar swivellig it around if needed.

Chorus will have almost no wireless licences by the end of this month so I'm sure they won't mind if their derelict kit is reused.

They cannot take it back without fixing the the chimney properly you see . That would cost them a fortune, best leave it up there.

M

cookie_mnster

Thanks for the info...I should have been a little clearer...the aerial does have a smaller UHF aerial and this is what I was wondering about.....

watty

Originally posted by Muck
you are saying in effect that much of the infrastructure required for Mesh radio technology in the 2.4Ghz band is kinda sitting all around rural Ireland.... mmmmmmmmm...pre-installed and all bar swivellig it around if needed.

Chorus will have almost no wireless licences by the end of this month so I'm sure they won't mind if their derelict kit is reused.

They cannot take it back without fixing the the chimney properly you see . That would cost them a fortune, best leave it up there.

M

Yep.
Of course the LOGICAL thing would be to use the 2.5Ghz Digital MMDS as Ireland's 30Channel freeview. With analog MMDS turned off someone could sell up to 90 pay TV channels on it too (Chorus uses 60ish channels because they receive analog MMDS ON THE SAME aerial!

I have a bunch of old 2.4GHz 2Mbit Wifi PCMCIA (Zoom) cards easy to fit a cable to. I'm going to put one on a satellite 1m center feed dish (what some foks call "prime Focus") and the other on an MMDS dish and dipole via an "N" connector socket. I might make it across the fields to the Office ADSL...