MMDS question

mate

Can anyone tell me what MMDS stands for or means?

celticfc

Multipoint Microwave Distribution System

Click here to see what it means

watty

Microwave Multipoint Distribution System...
or

Multipoint Microwave Distribution System...

or
Multichannel Multipoint Distribution Service

The USA has horrid versions and other places have decent versions.
Though the USA has a totally incompatible lower bandwidth/lower quality TV system, the Irish system is probabily unique on trying to put higher quality wider band European PAL over a system designed for NTSC in the USA.

Africa and Australia also have MMDS.
Thales, a supplier of MMDS claims to have customes in 70 countries.

The newest invation for MMDS is Metropoltian Fixed (non roaming) version of WiFi networking (Similar to 802.11, but designed for fixed base and fixed clients as in MMDS). Of course Chorus and NTL arn't doing this which gives cheap broadband to every home connected for Digital TV. Chorus "Power Net" may be a variation of this but "A" they don't really market it, "B" try getting it.

A fancy name to hide what it really is... Terrestrial TV via 2500MHz instead of 470MHz to 890MHz.

There are 3 main kinds:
1) Analog using AM video like ordinary TV. Generally depreciated.
2) Analog using FM video like analog Satellite or Broadcaster analog Microwave links.
3) Various Digital versions. CODFM is best for terrestrial , but don't I know if Chorus uses this or QAM or QPSK for their new Digital service. These are really a microwave DTT.


The Irish MMDS (Type 1) used/uses a mix of 3 systems:

a) Analog AM Video. Depreciated and very bad idea. They should have used FM Video.

b) US Cable TV set-top boxes and scrambling designed for 525line NTSC Color Cable signals. A very bad idea for MMDS and PAL. They should have used scrambling/encryption designed for PAL and using higher Quality European Set -top boxes instead of the Jerrold rubbish. Also the Jerrold system seriously limits "package variation" and is easily defeated as it is just simple scrampling rather than encryption. I WONT TELL YOU HOW so don't ask

c) 625 Line Analog PAL signal. This was mandatory to drive the TV Sets and by licence authority.

They also used fairly poor (noisy) Downconvertors (really an LNB).

The options at the time the system was proposed were:
1) The AM system, which could have been done MUCH better, with proper PAL encryption/scrambling boxes, in stead of US cable TV rubbish.

2)An FM system carrying PAL. Ordinary Analog satellite pay TV boxes (syster, videocrypt or whatever) would have been the receiver at a slightly higher price than the Jerrold descrambler. Higher quality than ordinary TV if the signal is good. If the signal is poor, it gives better quality than present AM Analog MMDS at same level.
Less channels or wider MMDS band, but less co-channel interference, so in the end would still allow 10 to 12 channels. Ruled out on cost.

3) YES, Digital MMDS already existed before the first MMDS subscriber was hooked up in Ireland. Ruled out on Cost. Allows 50 to 130 Channels depending on band size. They only wanted enough really for the 4 main UK TV channels. Didn't see potential of multichannel.


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Really it is only the Gov. (ODTR, Comreg later) that has forced the "upgrade" from the pathetic brain dead at birth Analog MMDS to the Digital one. But how well is it engineered? Does it use the "proper" modulation (CODFM) or are they using Digital Cable signals ovedr the MMDS and digital Cable set-top boxes? I don't know. If someone posts all the detials on
* Chorus Digital Cable Set top box (Sagem?)
* Chorus Digital MMDS set top box (It *IS* Sagem)
Then I'll find out (Make, Model name and code etc).