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[aprssig] Newbie Path Question

Steve Dimse steve at dimse.com
Sun May 17 12:54:20 UTC 2009


The idea behind RELAY stems from back in the days when APRS was young;  
users and digis were well spread out. Every home station was  
encouraged to respond to RELAY (as well as digis), and low power  
mobiles used RELAY as the first call in the path. This gave the best  
chance for someone hearing a low power mobile and repeating it into  
the digi network. As users and the network filled in, this generated  
multiple copies of the packet and caused QRM.

Many people still use old software, and many of those old programs  
configure a TNC to respond to RELAY automatically. This is most likely  
the source of what you are seeing. In other words, it is not a digi  
that is responding to RELAY, but a home station. When no one is  
transmitting with RELAY in the path this causes absolutely no harm and  
there is no need to chase down the guy. On the other hand, home  
stations changing to respond to current digi paths like WIDE1-1 can  
cause problems, so proceed with caution. If you really want to figure  
out who is doing this, set your path to RELAY, plug in a dummy load,  
and drive to each station on the map. One will hear you and repeat the  
RELAY packet.

Steve K4HG

On May 17, 2009, at 7:54 AM, Josh Smith wrote:

> I did some more playing around last night and this morning.  And it
> appears as if there is a digi closer to me than the ones on the
> aprs.fi map.  However it never ACK's anything unless I have relay in
> the path, which I understand is obsoleted.  How can I find out the
> call of this digi.  I would like to contact the owner and see if we
> can get it reconfigured with non obsolete settings.
>
> Thanks,
> Josh Smith
> KD8HRX
>
> email/jabber:  juicewvu at gmail.com
> phone:  304.237.9369(c)
>
> ()  ascii ribbon campaign - against html e-mail
> /\  www.asciiribbon.org   - against proprietary attachments
>
>
>
>
> On Sat, May 16, 2009 at 11:57 PM, Keith VE7GDH <ve7gdh at rac.ca> wrote:
>> Josh KD8HRX wrote...
>>
>>> I have changed this setting to relay,wide4-4 and things seem to be
>>> working much better now. I'm not very confident in my understanding
>>> of this setting but I believe that this means that my packet will be
>>> digipeated by up to 4 digipeaters before it "expires". Could some  
>>> one
>>> tell me if my understanding is correct?
>>>
>>> Also what is the difference between using wide and trace in the path
>>> setting and which should I use for my normal operations?
>>
>> You have already received some good replies from Ron and John. It
>> has unfortunate if there is still a digi in your area that responds  
>> to
>> RELAY. It has been obsolete in North America for something like 4-5
>> years now. If you did actually hit a digi that still responded to the
>> obsolete RELAY, the four additional hops from WIDE4-4 would make a
>> total of 5 hops which would be considered an overly long and abusive
>> path in most locations. Read up on the ALOHA principal. You should  
>> try
>> and keep your beacons within your own ALOHA circle. Any more than  
>> that
>> is just creating QRM.
>>
>> Most places in North America, WIDE1-1,WIDE2-1 will be the path to  
>> use.
>> If you really need a longer path, try WIDE1-1,WIDE2-2 but only if  
>> it is
>> really needed. You can always use "state flooding" if you truly  
>> need to
>> propagate something to greater distances than you normally need to  
>> go.
>> Such a path would be referred to as SSn-N where "SS" is the two  
>> letter
>> abbreviation for your state. It should be preceded by WIDE1-1 to make
>> it traceable... e.g. WIDE1-1,SSn-N where again, the SS represents  
>> your
>> state.
>>
>> Both the WIDEn-N and fill-in digis will respond to WIDE1-1, but if  
>> you
>> are heard direct by a high WIDEn-N digi, that's great. In WIDEn-N,  
>> the
>> "n" is the number of hops requested, and the "N" is how many hops  
>> remain
>> or are as yet unused. The digis that respond to WIDE1-1 only are  
>> called
>> "fill-in" digis. Their purpose is to help mobile stations make it to
>> higher WIDEn-N digis usually in hilly terrain or in the "concrete
>> jungle" in town. As each digipeater acts on your beacon, it inserts  
>> its
>> own callsign to make it traceable. The "N" is decremented when it  
>> goes
>> through the digi. When it reaches zero, the "N" is used up and it  
>> won't
>> be digipeated any further.
>>
>> Just remember that RELAY, WIDE, TRACE and TRACEn-N are
>> obsolete in North America. If you are aware of a digi that responds
>> to the obsolete RELAY, try and contact the operator and politely ask
>> them to update their digi's settings. The replacement for RELAY is
>> WIDE1-1.
>>
>> PS - you did the right thing in asking about your path! You can't be
>> criticized in initially using RELAY as it is one of the default  
>> settings
>> in the D7. While it is now obsolete at least in this continent, you  
>> can
>> now update your settings knowing that you are using the recommended
>> path for mobile stations.
>>
>> 73 es cul - Keith VE7GDH
>> --
>> "I may be lost, but I know exactly where I am!"
>>
>>
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