[HCARC] Fw: FW: SYSTEM FUSION NET

[Gary J - N5BAA]

-----Original Message----- 
From: Gary J - N5BAA
Sent: Wednesday, November 26, 2014 11:26 PM
To: Kerry Sandstrom
Subject: Re: [HCARC] FW: SYSTEM FUSION NET

Do you mean Kerry that "IF THEY BUILD IT - THEY (WE) DON'T HAVE TO COME"??
Heck, Bill Tynan recently put up a 900 mhz repeater at his cost and I'd bet
there are very few that have started using that one.  I might, but every
Alinco 900 mhz handheld I find costs me well over $200 (closer to 300)
dollars.  I then can make a choice to spend the $$$ on coax or antennas for
HF and sorry Bill - 900 mhz loses out.  I have asked on here if there is a
less cost 900 mhz radio out there, but to date haven't heard one suggestion.
The last thing I need to do would be buy a Fusion radio to have it sit idle
too.

BTW, for the new guys - VERTEX Standard makes Yaesu.

Gary J
N5BAA

-----Original Message----- 
From: Kerry Sandstrom
Sent: Wednesday, November 26, 2014 9:11 PM
To: Gary J - N5BAA
Subject: Re: [HCARC] FW: SYSTEM FUSION NET

Gary et al,

I think Gary has made a good comparison.  This is kind of like the Beta
vs. VHS VCR battles.  Many would suggest that that battle was one not by
the best technical system but the one that was least expensive.  There
are still people who are trying to keep Beta alive.  Unfortunately both
seem to have lost out to DVD and then Blu-ray.  There are some
differences however.  We don't have 2 competing systems - we have at
least 5.  The three additional ones are TETRA, the European LMR digital
system, P25 the US LMR digital system and DMR, another European LMR
system.  Because of FCC rules on bandwidth in the LMR bands, I expect
every public safety 2-way radio in North America will be a P25 digital
radio.  Same thing is happening in Europe except it will be TETRA.  Why
do hams want to create a different incompatible system.

All the systems claim compatibility with analog FM but none claim any
compatibility with other digital systems.  As a minimum, we need to wait
to see which system is the winner.  Cost will eventually be determined
by economy of scale.  Companies selling P25 radios include Motorola,
Codan, Harris, Midland and the commercial parts of ICOM, Kenwood and
Vertex Standard.

I don't have any idea of how the FCC will eventually react to these
systems in the ham bands.  Already, I believe the 2 meter band can't be
used for remote control.  I'm not sure what the restrictions are or may
be applied to 9600 baud data.

Some of the digital systems require linear amplifiers.  I don't know if
all do.  TETRA is one that I believe does require linear amps. Yes,
digital signals do and will cause interference.  Turning the squelch up
merely ensures that you won't hear weak FM analog signals that are
receiving digital interference.  That means some of the weaker analog FM
signals will not be workable.  Typical narrowband digital signals
require a higher S/N than analog FM, that's why the coverage of the
digital signals is not as good as the analog signals.  Error correction,
FEC, and coding help with pulse type interference but do little for
continuous interference. Unfortunately the response of most digital
systems to interference is to retransmit the messages that can't be
decoded probably.  This doesn't exactly help the interference situation.

I'm not sure what compatibility really means in the case of repeaters.
What I think it means is that a digital signal will be repeated as a
digital signal and an analog signal will be repeated as an analog
signal.  I don't think a digital user will be able to talk to an analog
user.  I may be wrong, but that is how I interpreted compatibility.

So where does that leave us?  Digital and analog on the same repeater
simultaneously is not realistic.  When both are present at the same
level, I think digital will suffer more than analog. Digital coverage at
the same power levels will be less than analog. I would wait until there
is a real standard with real support. Right now, I don't think either
Dstar or Fusion will be that standard.  Finally, yes there are a lot of
fun things you can do with data, but I don't know how many of them are
legal, especially in the 2 meter band.

No, I'm not a fan of digital systems on the ham bands.

Kerry










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