[aprssig] Kenwood's DX List

Bob Bruninga bruninga at usna.edu
Sat Dec 18 08:53:29 CST 2010

> I've recently learned that the Kenwood APRS 
> radios have something called a "DX" list.  
> ...Whats the packet format.. in this special list?

Yes!  This is a very powerful way to send information to an HT or mobile operator.  I use it to send "lists" of info.  Such as my APRSdata program that generates local objects whenever an FM satellite is in view that people can work with their HT or mobile radio.

The program sent out objects that appears like this on the popup display once a minute:

AO51         < Satelite name
435.375+5    < Downlink Freq + Doppler 
145.930-5    < uplink freq + Doppler
HIGH         < Whether it was high or low in sky

This enables anyone in the region that is mobile at the time to instantly QSY his radio and work some satellites.  It is easy to do a 2way FM mobile contact via AO51 when it is HIGH.  This lasts about 3 to 5 minutes max.  But if you dont know when that is each day, then 99.99% of mobiles don't play this game.

But if it shows up on APRS as instant real-time info (What APRS was designed to do!) then it is a come-as-you-are opportunity!  You can work satellties during your daily commute!

Now, what about that GREAT satellite that might just be coming up 3 minutes after you arrive at work, and you would stay in your car to work it if you knew it was coming?

That is how I used the DX list.  Once every 10 minutes, a LOCAL DX LIST packet goes out that contains (in 1 packet) the SCHEDULE of the NEXT 4 satellites.  This way, before one shuts off the car, one can press the DX list button and see the schedule and see if there are any worth sitting in the car and waiting for.

Back in 1998 or so when I wrote APRSdata, there were almost 18 AMSATS that one could hear from the mobile.  There was almost always something coming over during a commute.  Now the numbers are smaller, but still as exciting.

I sure wish someone would re-write APRSdata.EXE to run on windows, since no one runs it much anymore.   BUT!  Other authors did put in the functionality.. I believe DIGI_NED can generate these objects.  Also maybe even INFO_KIOSK?

Oh, one last thing. APRSdata also sent out the code to make D700's with the VOICE chip actually SPEAK the above satellite-in-view info.  So you could just be driving down the road and your radio would say:  "AO51 HIGH" wihtout you even looking at the radio.  Then if you had the satellite programmed into a memory channel or PM,  you couild work it easily.

APRS can be such a powerful REAL-TIME LOCAL INFO display device for the mobile operator and that is why it is SO frustrating that no one does anything like this anymore...

Oh, the format should be documented in my many documents.  The description of the above APP is in www.aprs.org/astars.html about 60%? down the page?

You can also try www.aprs.org/APRS-docs/DX.TXT or /SPACE.TXT

I have a slow internet at home so cant easily search..


> Does anyone know what the packet format is to put
>something in this special list?  Is it simply a symbol of /% (DX
>Cluster) or \d (DX Spot) or both?  Is there anything out there that
>actually generates such packets and what are the guidelines around such
>Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32
>PS.  I did see "DX CLUSTER Live last two hours worth of DX spots plus
>information on DX." on http://www.aprs.org/, but the link to
>http://www.ew.usna.edu/~bruninga/dxspots.html doesn't work any more.
>PPS.  http://aprs.org/astars.html talks about satellite schedules
>showing up in the DX-LIST and/or DX-SPOT, but again, nothing definitive
>about the packet format to put stuff there.
>PPPS. http://homepage.ntlworld.com/ajmckinnon/aprs.htm mentions "A
>modification of this is a "DX query", which again sends a different
>ASCII code to which the other system replies with information of the
>best DX in its current station list, ignoring stations heard via
>digipeaters.", but still no details.  If you're going to go so far as to
>say "different ASCII code", why not just say it's a "?APRSxxxx" and
>provide the detail?
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>aprssig at tapr.org

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