Re: SAW Filter limitations

"John D. Hays" <john@...>

Hi Steve,

Currently, the only DD network implementation is 128 kbps on 23 cm from Icom (ID-1 terminals, and RP-2D access point) and is half duplex (no repeaters).  The UDRX will change this, as it will permit DD at data rates from 4.8k to the top data rate (estimated to reach 100k+) of the radio using 70cm band(s). In the US we are limited to a 100 kHz channel.

In the Icom architecture DD is always a separate band module.  With the UDRX we have the potential to run both DD and DV on the same module (at 4800bps).

It may also be possible to build a repeater having 100 kHz channels using the UDRX. (Either bonding 4 adjacent 25 kHz channels at 440 band or using a split in the 430 band.)

DV (which includes a slow data subchannel) is typically simplex, repeated, or simplex access point (hotspot).  This is  a 6.25 kHz channel (or repeater pair).  In the US DV repeaters usually are following the local band plan.  Here in Western Washington (State) we use high in/low out for our repeater pairs and the bandplan has 12.5kHz and 25kHz pairs. 

John D. Hays
PO Box 1223, Edmonds, WA 98020-1223 

On Mon, Mar 17, 2014 at 11:01 AM, Steve <yahoo-udr@...> wrote:

How does this discussion affect digital voice (DV) and digital data (DD)
modes in the USA? Do DV repeater operators always enable DD capability?
Or, are there separate DD repeaters? Do the repeater operators follow
the ARRL or other local band plans?


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