MMDS System - STBs ?

HarryD

I'm interested to find out about the MMDS system
Does anyone know do they use STBs or not ?
If so what make/models ?

Also as regards analogue cable in Cork city,
I believe it is different to anywhere else in Ireland ?
If a user in Cork opts to no longer subscribe to the
service, can NTL/Chorus disconnect them remotely ?
(without a site visit)

TIA
HD

watty

Analog and Digital are very different. But both are 2.5GHz, allowing a much more open mesh dish than Sky (11GHz) or even C-Band Satellite (3.5GHz).

The Analog uses an LNB (downconvertor) often for "VHF/Hyperband). You can power it from 12VDC via an RF choke / DC block capacitor to TV and tune any "clear" channels"

The Jerrold is the totally rubbish US Cable NTSC TV set top descrambler used to decramble any "coded" channels (most of the 10, 11 or 12).

The Digital System also uses an LNB on the minidish to down convert.

The set-top box are Sagem Digital Receivers, similar in concept to DTT Freeview boxes, Cable Digital or Sky Digibox. But incompatible. It uses Digital Encryption rather than the rather stupid picture impairing "scrambling" unravelled by the Jerrold.

The Analog system can't be other than poor due to its staggeringly bad (and obsolete before installed) design. The Digital system can be as good as Sky if the fit and operate the Transmitters properly (Sky Installers fortuanately have no access to the Satellite 22,500 miles away), and fit and align the Receiving dish properly.

It needs fairly much "line of Sight", like WireLess LANs do. Most of the problems on Digital MMDS are poor alignment/install of dish and/or poor line of site.

Since Satellite is about 23 Degrees upward, and MMDS is horizontal, Line Of Sight is a big problem for MMDS. Though with a strong signal, obstructions that would block Sky will be OK on MMDS Digital. On Analog they would create nasty Ghost Images.


Unlike Sky, Freeview and Terrestrial Analog TV, MMDS is classified as a "wireless cable" system so you can't buy a set-top box. To operate a setop box (Analog or Digital) for MMDS without correct NTL/Chorus subscription is "Cable Tapping/Piracy" and has very big fines. Criminal Offence.

Channels that you pickup without ANY Chorus/NTL/Set-top-Box and are "clear", i.e. not encrypted are technically a "free to air" broadcast. If you using anything more than a TV / VHS to watch them or they encrypted/scrambled in any then you breaking the law.

If you watch TV3, C4, Chours/Bravo channel from Woodcock hill with your own "MMDS" dish and LNB and simply feed a TV with channels Chorus is silly enough to transmit "clear" then you arn't breaking any law AFAIK.

people buy "MMDS" dish to use for "licence free" Wireless LANs on 2.4GHz

HarryD

Thanks for the reply watty ..

Originally posted by watty

The Jerrold is the totally rubbish US Cable NTSC TV set top descrambler used to decramble any "coded" channels (most of the 10, 11 or 12).

I didn't fully understand you..
Do they use Jerrolds for analogue MMDS ?

people buy "MMDS" dish to use for "licence free" Wireless LANs on 2.4GHz

Interesting.. I might try and get my hands on one..
Don't suppose you know the scope of these antennas ?
How far can they communicate with WLAN ?

Cheers,
HD

watty

The "Jerrolds" should have been banned an import licence.
It is a US TV cable descrambler.
Designed for lower bandwidth 525line NTSC rather than 625Line PAL.

Unbelivably they use AM microwave transmitters for Analog MMDS, (Anything else, ever uses FM video for analog).

The whole Analog MMDS is just run like a USA cable system that happens to have AM microwave links in the middle. Then they feed it with PAL and "non-one" wonders why picture quality is so poor!


8km is typical for ordinary office Wireless LAN gear on MMDS aerials. 38Km has been alleged in Ireland.

Certinally 10Km easily possible, LINE OF SIGHT on MMDS aerial/Dishes

Cheap Omni antenna for WiFi
http://www.solwise.co.uk/wireless-outdoorantenna.htm

Cheap Dish antenna fo WiFi
http://www.vbnets.com/products/hardware.php?cat=antenna

Digital MMDS
It would NOT surprise me if Chorus is using Digital Cable QAM signals and the Sagem box is just their Digitial Cable Receiver / Decoder.

Digital MMDS *OUGHT* to use CODFM signalling and need a different box to cable.

Historically Broadcast in this counrty was based on Politics/ Fat Cats, not sound consumer orientated technical facts.

Hopefully Comreg will prove to be a new broom.

spuddy

Originally posted by watty
The "Jerrolds" should have been banned an import licence.
It is a US TV cable descrambler.
Designed for lower bandwidth 525line NTSC rather than 625Line PAL.

Unbelivably they use AM microwave transmitters for Analog MMDS, (Anything else, ever uses FM video for analog).

The whole Analog MMDS is just run like a USA cable system that happens to have AM microwave links in the middle. Then they feed it with PAL and "non-one" wonders why picture quality is so poor!


8km is typical for ordinary office Wireless LAN gear on MMDS aerials. 38Km has been alleged in Ireland.

Certinally 10Km easily possible, LINE OF SIGHT on MMDS aerial/Dishes

Cheap Omni antenna for WiFi
http://www.solwise.co.uk/wireless-outdoorantenna.htm

Cheap Dish antenna fo WiFi
http://www.vbnets.com/products/hardware.php?cat=antenna

Digital MMDS
It would NOT surprise me if Chorus is using Digital Cable QAM signals and the Sagem box is just their Digitial Cable Receiver / Decoder.

Digital MMDS *OUGHT* to use CODFM signalling and need a different box to cable.

Historically Broadcast in this counrty was based on Politics/ Fat Cats, not sound consumer orientated technical facts.

Hopefully Comreg will prove to be a new broom.

Which of the aerials/antanae on VBnets would be suitable to pick up any analogue MMDS transmittions?

watty

The mesh dish one that looks identical to an MMDS aerial!

Go for biggest as signal is usually poor.

Stella Doradus 24db Parabolic Mesh Antenna
24-SD27
Professionally made, economically priced mesh Antenna
Price: €50.00 ex Vat, €60.50 inc Vat
This item costs €30.00 to ship in Ireland, charges may differ for overseas.

You need an LNB / Downconvertor (Cost about £100 stg) for 2.5GHz to TV band to be able to feed a TV. The dish on its own can only be used for Video Senders and WiFi networks, and even for these you need very short cables, N-Connectors, adaptors etc.

Remember it is ILLEGAL with BIG FINES and all equimpent inc TVs etc confiscated to receive any SCRAMBLED channels or use a Cable / MMDS settop box with out paying correct subscription.