[aprssig] Kenwood APRS Display Paradigm Shift

Stephen H. Smith wa8lmf2 at aol.com
Mon May 23 12:59:10 EDT 2011

On 5/23/2011 8:26 AM, Bob Bruninga wrote:
> The new D710 Firmware was available at Dayton!
> This release represents a PARADIGM SHIFT in the display of APRS data on
> mobile radios.  What they added were two instant-awareness features:  1) an
> INTERRUPT ALWAYS mode. And 2) a display of your OWN path each time you are
> digipeated so you can not only see that you got out, but by what digipeater.
> These are invaluable to the real time situational awareness of the mobile
> operator.
> When INTERRUPT ALWAYS is set, every packet heard now flashes its data on the
> screen for a few seconds so that the APRS junkie is continuously aware of
> what is going on around him.  He does not have to use any hands to see the
> APRS situation...  It was a joy riding back from Dayton and seeing
> everything going on in the areas I passed through.

This is essentially what the packet data monitor at the bottom of the UIview 
screen on my mobile laptop does.

> I never realized how debilitating this was because I live in the middle of
> the highest density APRS activity in the world (Wash/Baltimore area).

Can it really be that dense?     Greater than Los Angeles?    Day in and day 
out, the UI-Traffic monitor display at my station here in Pasadena, CA (about 
10 miles NE of downtown L.A). is showing 25-35 packets a minute; i.e. about one 
every two seconds any time of the day or night.

UI-Traffic Analysis here:

Any display that shows only the most recently heard packet will never show it 
long enough to be read before it gets pushed out by the next one around 
here.    That's why I often pop the "terminal" display in UIview that shows the 
last 10-15 packets.  You get a continuously downward-scrolling display that 
gives you the chance to see a given packet for 20-30 seconds before it gets 
pushed off the bottom of the screen.

[On a related note, the companion APRS Network Analysis plugin for UIview 
compiles lists of stations heard and breaks them down by path usage.   For the 
FIRST TIME EVER around here, an entire week (with over 700 different calls 
heard) has passed without  A SINGLE RELAY or plain WIDE showing in the list   
There has been a small number of stations using RELAY,WIDE paths persisting 
until now, probably due to outdated default setting in D700s or outdated 
instruction manuals on radios. ] .

Network Analysis here:

> This problem was therefore not noticed by most heavy APRS users until the
> D710 came out with a depth of 100 stations in the station list.  Then I
> began to see even this effect in the Baltimore area.  All I would see would
> be "DP W3AXY" meaning it was a duplicate packet that I had heard sometime
> before maybe even days ago, and so it would not flash the info!  ARGH!

Here in L.A., this starts happening within 15 minutes on my D700 any time you 
clear all the station lists.    I guess a D710 would stretch this to perhaps 
half an hour or 45 mins.

> For the APRS junkie that wants to be immediately informed on everything
> going on in ham radio around him, that is on the air (what is in those
> packets???) then this had to be fixed.  SO now it is.  Now you can see
> EVRTYHING the instant it comes in.  This is how the add-on text displays on
> the Tinytracker and other trackers have been working for a while.
> The only down side is when you want to use the radio for actual radio and
> the screen is being interrupted so much, it is hard to see what you are
> doing.

This is the huge advantage of the external mobile laptop display - the radio's 
own front panel is NOT constantly blinking and and shifting. As I mentioned in 
my SSTV post, consider a cheap ($225 or so) netbook mini-laptop.   It's 8.9" 
screen is infinitely superior to anything that will show on the front panel of 
a radio, and can display far more map than even the largest car navigator GPS.

In cars with extremely raked-back windshields that yield very large top-of-dash 
spaces (like the Prius) the netbook can actually fit on top of the dash (unlike 
full-sized laptops) and yield effectively a heads-up display similar to a car 
navigator GPS stuck to the windshield.

Netbooks are now considered passe in the mainstream consumer PC market, having 
been overshadowed by tablets.  However they make ideal building blocks for all 
sorts of ham related applications.  They are actual miniature X86 PCs with USB 
ports, Ethernet and WiFi connections, 120 GB or larger hard disks, and normal 
(if shrunken) keyboards, that can run "normal" Windows PC software.   These 
low-power light-weight (about 2 lbs) mini-PCs will run 3-4 hours on one battery 
charge, and with the optional oversize replacement pack, I have run my Acer 
Aspire ZG5 for up to NINE hours on one charge.

I have used my Acer connected to a TH-D7 in "PACKET" mode as a complete 
self-contained battery-powered "porta-mini-igate" setup at ham club meetings 
via it's built-in WiFi.    I have used it's sound system connected to the TH-D7 
speaker/mic jacks (and again the WiFi)  for an instant portable EchoLink node. 
       I have done the  entirely-software-based  APRN setup (as noted in my 
SSTV post)  with AGWpe, mmSSTV, EasyPal and UIview running at the same time 
(and again the built-in WiFi) on the same netbook connected to the 6-pin 
mini-DIN "data" jack of a Kenwood TM-G707.

[Kenwood hand-helds use normal dedicated PTT lines (just like full-sized 
mobiles) rather than the screwball "draw-DC-through-the-mic-element-to-ground" 
PTT scheme used by most hand-helds to save one mic plug contact.  This makes 
integrating external sound card apps a lot easier.  You don't have the 
nuiscence of having to combine TX audio and PTT on the same line.]

Due to being no longer fashionable in the mass market, netbooks are available 
cheap; I have seen some being blown out on NewEgg.com and TigerDirect.com for 
$190 at times.    And cheaper still second-hand at ham fests.

> This is easily solved by momentarily just hitting the CALL button on
> the A side of the radio to QSY off the national channel for a few moments of
> peace while you play radio.

I do essentially the same thing for testing and checking out new APRS gadgets 
and settings. I have the CALL button on all my 2M radios set to 144.370 so I 
can jump off the public 144.39 channel, down one channel, instantly when needed.



Stephen H. Smith    wa8lmf (at) aol.com
EchoLink Node:      WA8LMF  or 14400    [Think bottom of the 2M band]
Skype:        WA8LMF
Home Page:          http://wa8lmf.net

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"APRS 101"  Explanation of APRS Path Selection & Digipeating

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