Friday, Aug 26, 2011 at 11:13
The "digital ready" hype is just that, and nothing more than a sales plug, like digital-ready tv antennas. The mode of transmission is analgogue, unlike say,
police radios, which are digital modulation.
The 40 channels have been cranked out to 80 channels by interleaving the extra channels between the existing channels; ie, the channel spacing has been halved.
And bringing it into line with commercial VHF and UHF channels which have been using the spacing for years.
Two issues:
The receivers on the new 80ch sets have a narrower bandwidth to suit the new channel spacing
The transmitters in the new 80ch sets transmit a narrower bandwidth.
It is possible that some of the transmssion from an old wide-bandwidth 40ch set will spill over into the adjacent 80ch frequencies, creating interference.
Similarly, it is possible that intermediate 80ch frequencies will interfere with one of the 40ch frequencies, as the 40ch receiver bandwidth is too wide to reject it.
So bascially, there are interference issues between the two standards which is why the 40ch sets be eventually phased out. In reality, you would probably only experience this in buit-up cities.
Unless you're offered a 40ch for almost free, I'd be buying an 80ch.
Check out
Prestige Communications.
cheers
Gerry
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