Interesting suggestions, Skip.
We're hoping to be installing UHF and VHF vertical yagi's at the
Skyview Radio Society before winter sets in. I'll be sure to do some
weak signal work with the DominoEx 8 as you suggest.
-Dave, KB3FXI
--- In digitalradio@yahoogroups.com
<mailto:digitalradio%40yahoogroups.com>, KH6TY <kh...@...> wrote:
>
> The reason to use DominoEx is only for FM DX communications. It is
> slower than MT63, but much more sensitive, so you still get good copy
> way below limiting and quieting. For that reason, on our local FM
> digital net, we use DominoEx 8 and with horizontally polarized
antennas,
> include everyone in a range of 35 miles.
>
> I suggest trying MT63-2000, and if some stations cannot copy, drop down
> in speed to MT63-1000, and if necessary, drop down to MT63-500. Then if
> you still have problems with some stations not copying, go to
DominoEx 8.
>
> If any station is below limiting, which is quite possible at 25 miles
> using low verticals, MT63 may not work.
>
> On UHF, where Doppler shift and Doppler spreading is a major problem
> with SSB voice, we use Contestia 64-1000, which works very well on 200
> miles paths.
>
> 73, Skip KH6TY
>
> On 7/19/2010 7:58 PM, KB3FXI wrote:
> >
> > Jon,
> >
> > Here in WPA we've adopted MT63 2k long (64 bit) interleave as our
> > standard. The mode is very wide (2000hz) but fits very nicely inside
> > the typical FM transceiver and repeater audio passbands.
> >
> > Here's some of the big advantages of MT63 2k long on FM:
> >
> > -Massive amount of FEC (forward error correction) and interleaving
> > provides perfect copy, even under horrendous simplex conditions and
> > weak signals into repeaters (it even barrels through short drop-outs
> > and heavy noise with weak stations into our local UHF repeater)
> >
> > -There's no need to have to tune on the waterfall as all MT63
submodes
> > in FLDIGI are fixed at a bottom waterfall frequency of 500hz (2k long
> > goes from 500 - 2500 on the waterfall)
> >
> > -WPM rate is about 200wpm
> >
> > -Works fine using only a hand mic on the computer speaker and the
> > computer mic somewhere in the vicinity of the received audio from the
> > transceiver
> >
> > We run over UHF/VHF traditional voice repeaters and simplex
> > frequencies with great success on our net every week... even with
> > first time users.
> >
> > Please give it a shot and let us know how you make out. Also, make
> > sure your ops do a proper sound card calibration. You only have to do
> > this once, unless you change your sound card or switch to a USB mic.
> > Here's a video I made on that subject of calibration using
CheckSR.exe
> > and FLDIGI:
> >
> > http://www.utipu.com/app/tip/id/9382/
> >
> > -Dave, KB3FXI
> > www.wpaNBEMS.org
> >
> > --- In digitalradio@yahoogroups.com
<mailto:digitalradio%40yahoogroups.com>
> > <mailto:digitalradio%40yahoogroups.com>, "JonP" <jperelst@> wrote:
> > >
> > > I have the need to set up some reliable local digital
communications
> > (say 10 mile radius from the base station) for data transfer, and to
> > do so in a short period of time.
> > >
> > > I would normally first think of VHF FM packet, but a lot of people
> > are running into troubles with things like Vista and Windows 7
> > (please, spare me the "Linux" or "Apple" and "D*Star" messages,
> > they're not realistic in this situation).
> > >
> > > I've seen some references to running DominoEX and MFSK-16 on VHF
FM.
> > A number of my prospective operators are running digital modes
such as
> > DominoEX, MFSK, etc. on their computers now (under XP, Vista, Win7)
> > without problems.
> > >
> > > Would one of those modes be realistic to run on 25 watt (or higher)
> > mobiles on 2 meter FM using vertically polarized antennas? I realize
> > that the vertical polarization would be an issue if we want to get
out
> > of the local area, but right now the need is within a local area and
> > everyone would be running with a typical VHF vertical.
> > >
> > > If feasible, what sub-band would we use? I would assume the FM
> > simplex sub-bands. Is that correct?
> > >
> > > Anything else we should consider? Any special issues/problems? I
> > would think that we would not have to reduce power since these radios
> > are already running FM, but if not the case please correct me.
> > >
> > > Thanks.
> > >
> > > Jon
> > > KB1QBZ
> > >
> >
> >
>