[MNAPRS] APRS UHF 446.175

[W. S. Mitchell]

Hi Doug,
  In addition to this reply, I've copied my previous at the bottom,
now that I'm on the reflector.

Evidently I'm confused about the various WIDEn-N paths, and how those
are handled in digipeaters.  Here's how I understand it:
* NONE does exactly what you would think: no digipeating.
* WIDE1-1 gives you one hop, from any digis within range.
* WIDE1-1,WIDE2-1 is a hack to achieve the first hop of WIDE2-2 with
older gear that only recognizes how to handle WIDE1-1.  Some
infrastructure digis may be programmed to ignore the initial WIDE1-1
and simply finish it off as WIDE2*, but I wouldn't trust that to be
the case.
* WIDE2-1 gives you one hop from any modern digi that understands the
WIDEn-N system, but is missed by the older ones that only recognize
WIDE1-1.  This isn't (?shouldn't be) used as an actual path, except as
WIDE1-1,WIDE2-1 above.
* WIDE2-2 isn't used, because it has been effected by the
WIDE1-1,WIDE2-1; gives two hops.  I'm ready to deprecate the
WIDE1-1,WIDE2-1 format and use the WIDEn-N system properly.
* WIDE3-3 or WIDE1-1,WIDE2-2 gives three hops (if the digis allow it!)
and should be used very sparingly, only in outstate areas for
important messages.

Based on the understanding above, fixed or infrastructure stations
should use NONE or WIDE1-1 only (probably NONE).  Attended stations
(e.g. mobiles) might reasonably use WIDE2-2 (or the equivalent
WIDE1-1,WIDE2-1), but I personally haven't found much reason to send
packets that far out.

Thanks for the link to the hamvention video, and the explanation of
voice alert.  Using a 100 Hz tone on 144.390 seems like an interesting
alternative to 146.52 MHz, and yes, moving to somewhere not 146.52
would be needed (146.52 being a calling frequency not an operating
frequency).  I might end up using that in combination with the voice
frequency status message, so those who don't use voice alert could
reach me.

Regards,
  Bill
AE0EE



***

Greetings,
  Not to speak for Matt, but part of the reasoning for going to 9600
baud UHF is to get away from some of the poorly-configured
infrastructure on 144.390.  Much of the time here in the metro area,
it isn't really an issue if digis or other automated stations are
digipeated more than once (I am of the opinion that there is very
little need for a digi to use anything beyond WIDE1-1, and even that
may be unnecessary).  However, when the band opens (e.g. tropo), the
channel can get flooded with unattended infrastructure stations that
are conveying relatively little useful information.  Even with a beam
I probably couldn't hit that digi in Omaha which sent a
WIDE1-1,WIDE2-1 packet.

By going to 9.6 kbps UHF, even if the 8x throughput increase isn't
realized, it would at least clear up the channel a bit.  It is
consistent with the experimental nature of ham radio, by trying
something a bit different---even if it does not end up working as we
had hoped.  It would also encourage use of the 70 cm band.  I have
found the http://aprs.mountainlake.k12.mn.us APRS propagation site
very useful for 2 meters, and having something similar for 70 cm could
be nice.

To me, the advantages are to get away from the flood of infrastructure
station packets, to get onto a different band, and to have a space
which perhaps would see some use from attended stations---be they
mobiles, handhelds, or base stations with someone nearby.  When
attended stations list their voice frequency (particularly in the
appropriate format), it does make it easy to establish contact with
them.  Remember: APRS is supposed to be about sending useful
information and enabling two-way communications.

Regarding the 2-way I-gate, the W0YC-5 digi is just that.  There is
some configuration which goes into it, for instance how recently it
heard a station which an APRSIS message lists as a recipient, but at
least that one seems to have been done well.  I have tested it with a
friend in CA, and it works as intended.  We've even done a test
message or two with 30 m PSK63 on his end and 2m on mine.

Thanks for the heads-up on the video; I haven't had time to watch it
yet, but will queue it up for when I have a moment.

Regards,
  Bill Mitchell
AE0EE

On Fri, Jun 3, 2016 at 5:25 PM, Doug Reed <n0nas at amsat.org> wrote:
> Regarding infrastructure beacons, i.e. local repeaters, club meetings,
> or other non-APRS informational beacons, I agree with WB4APR that they
> should be strictly local beacons, not even WIDE2-1 and especially not
> WIDE1-1. He also suggests those beacons should be transmitted by the
> WIDE-area digis because they are the only stations that really know
> when the frequency is clear. The purpose of the infrastructure beacon
> is to alert travelers coming into the area what repeater frequencies
> or club activities are happening. I don't think there is any reason to
> push those beacons any further than the digi can be heard direct. It
> does no good to tell a mobile about a repeater 100 miles away if they
> will travel another hour before they can talk to it.....
>
> I'm glad to hear that W0YC-5 is doing a proper job of reverse gating
> APRS messages when the recipient is in our local area. I personally
> have little use for APRS messaging but at least it is being done
> right. I can see that it could be valuable, I just haven't needed
> it.....
>
> I do like the Mountain Lake web site for indicating possible 2M
> openings. Of course by the time APRS indicates an opening, SSB would
> have been active for a while. But APRS-as-an-indicator does answer the
> old if-a-tree-falls-in-the-forest question. If nobody transmits,
> nobody knows there was an opening. So it is not a question of being
> able to hit the Omaha digi that was heard in Mpls. The idea is that
> you now know the band is open so get on simplex or move down to
> 144.125MHz SSB and make some noise.
>
> All the propagation sites I check have exactly the same problem, very
> few stations from MN, ND, SD, MT are participating so you don't know
> how far the opening extends. So if you can come up with a good way to
> get more hams in those states to put a beacon OTA, it would certainly
> help, particularly 6M, 10M, and 15M. WSPRnet at the 0.1W to 5W level
> seems to be a good option..... A lot of the software for digital modes
> has an option to keep listening when you are away from the radio and
> keep reporting the stations it hears to the propagation reporting
> sites. We need more dedicated beacon stations and more RX-only lurkers
> too.
>
> You mention being able to find attended stations to talk to using
> APRS. That is pretty much what the "Voice Alert" idea is about. It is
> primarily for mobile to mobile but base stations or portables could
> play too. Listen to the APRS forum video for the full description. It
> was primarily intended for radios like the D700 with APRS built-in.
> The main idea is that you program at least two APRS channels into your
> radio, One is the plain 144.390 with no PL tone, the other is 144.390
> with RX-TX PL tone of 100.0 turned on. A home station would program a
> third channel with RX PL but not TX PL since you are too likely to
> walk away from the radio and forget to turn off the PL.
>
> When you are mobile and want to talk, you use the APRS channel with PL
> enabled. If you hear a squawk from the radio it means that station was
> transmitting PL100 so you can look at the display to see who the
> station was because they are within simplex range and want to talk.
> You pick up the mike and TX back to them on 144.390 voice, giving
> their call, your call, and saying it is a voice alert reply so they
> know what frequency to call back on. You then take the conversation to
> simplex or a quiet repeater. Be advised that 146.520 is not the only
> 2M simplex frequency, 146.490, 146.550, and 146.580 work just fine as
> well....  :-)
>
> I think you are correct that all the local WIDE digis will respond to
> WIDE1-1, but if you are thinking of using WIDE1-1 on a fixed station
> to reduce repeats, I'd say no, and suggest the home station use
> WIDE2-1 instead. A fixed station should always be able to hit the WIDE
> digi so it should never need the "hit everyone" that WIDE1-1 would
> give. I'd say it would be counter-productive because the home station
> that replies to WIDE1-1 is more likely to be setup incorrectly and
> might help generate another packet storm. I still want to use WIDE1-1,
> WIDE2-1 for mobile or portable stations because they may need the
> local home station for the first repeat when out of town.
>
> If you are think specifically about home stations that beacon
> infrastructure messages, I'd suggest they would be better configured
> if they use the callsign of a specific WIDE digi that covers the area
> of interest rather than use a generic WIDE1-1 or WIDE2-1 path.
> Although if the infrastructure repeater has really wide coverage like
> 146.850 or 146.700, you might need the extended coverage that WIDE2-1
> would provide. But most voice repeaters in our area are at their limit
> with 25-30 mile range so a local beacon from a single WIDE would
> probably be all that is needed. At least that is my opinion and
> subject to change.....
>
> If you want another interesting project, you could consider installing
> an APRS receiver on the 145.825MHz satellite APRS downlink frequency.
> I-gate the packets and take a look to see if there would be any
> interest in repeating them on 144.390 also. I'd think it might be fun
> to have the packsats and ISS whizzing across the APRS map. And it
> would generate interest and show anyone when they are making a pass.
> It would be a good use for a KPC-4 and second radio..... Collecting a
> mix of data to retransmit on UHF 9600 would be the best way I could
> see to make it worth while.
>
> I just checked the ARISS.net web page and it looks like KD0KZE up in
> Circle Pines is on 145.825 but I can't tell if he is acting as an
> I-gate or only sending beacons. Also, the last position beacon
> reported on aprs.fi from RS0ISS was back in April...... Maybe they are
> not sending them any more....
>
> Bill, your reply message to mnaprs got hung up. I'll kick it loose as
> soon as I remember what the admin password is for the reflector. :-)
>
> 73, Doug Reed, N0NAS.