[App_rpt-users] Non-RTCM voter, where?
rhyolite at leikhim.com
Wed Mar 30 16:53:38 EDT 2016
What is the problem with the RTCM and simulcast?
Analog simulcast may never sound as good as a single site, because it
does experience/cause time differential interference and noise and
therefore requires some very specific design constraints. However, for
some applications it still is the way to go. Moving forward 5-10 years,
two slot DMR with IP connectivity will be the way to go. Before I get
flamed, TETRA never got a foothold in the US and because FCC eliminated
most 25KHz channels, getting TETRA to play in the US is reserved for
those few who have the contiguous spectrum.
I will confess to being a lurker here, primarily because I have
interests both in the commercial LMR and the "ham radio". The RTCM and
IP Simulcast support interests me because I have done a lot of simulcast
design work in Public Safety and the commercial support of analog
simulcast is becoming threatened with the loss of Raytheon JPS SNV-12
product. Also the commercial products are very pricey and complex. That
being said, I see the RTCM as having some potential niche in the
commercial LMR world.
On 3/30/2016 2:52 PM, Steve Wright wrote:
> On 31/03/16 05:28, Jeff Ackerman wrote:
>> XIPAR does not do GPS timing of the audio so there will be no timing
>> of audio. Its called "simple voter", no frills. XIPAR simply
>> selects the best receiver based on DSP signal strength measurements.
> Obviously the 'no timing' situation is not completely traumatic for
> the conversational use of the repeater, as there is no widespread
> comments or negativity about it.
> The RTCM is a good idea and a good design, but with the Simulcast
> transmit not functioning, and no apparent developer activity there's
> just not enough light at the end of the tunnel to commission it
> It seems to me that analog simulcast transmit is never really going to
> sound right. I feel uneasy about the relentless approach of digital
> audio into ham radio, but maybe the dream of zero-handoff multi-rx
> multi-tx systems means 'digital' and we're stuck with it. I'd like to
> be proven wrong on that.
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Leikhim and Associates
JLeikhim at Leikhim.com
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