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[aprssig] TH-D72 Manuals -- Quick First Viewing

Stephen H. Smith wa8lmf2 at aol.com
Wed Dec 1 06:59:28 UTC 2010

On 11/30/2010 2:39 PM, Mike Edwards wrote:
> Great thanks to Kent for posting about the software, it spurred me to look 
> around on the Kenwood site and see if I could find the manuals for the D72. I 
> used the search feature and found them.  Here are the links for the English 
> versions.
> http://manual.kenwood.com/en_contents/attachDownload/7736/  (small version 1.3MB)
> http://manual.kenwood.com/en_contents/attachDownload/7742/  (larger version 
> 6.5MB)

The "small" version above is an introductory "Get Started" guide.

The "larger" file above is a clumsy concatenation of what were EIGHT separate 
PDF files on a CD-ROM into a single 75-page PDF with no common page numbering 
and no PDF hot links in the table of contents.   The eight original PDFs each 
covered one topic such as "Operating Through Repeaters", "Memory Channels", 
"GPS", "Packet", "APRS", etc.

I've downloaded the two manuals from the website and have gone through them 
quickly.  Here are some first impressions.

1)   The relentless progression of Moore's Law (that posits that the number of 
transistors in processor and memory chips doubles every 18-24 months) is 
dramatically evident.   Although the radio superficially looks like the TH-D7, 
the number of functions, capabilities and memory capacities has increased 
dramatically.   For example, the internal GPS is supported by a 5,000-point log 
file in the radio's memory that can record your movements, even without 
transmitting over the air APRS posits.

2)   The computer interface port (that was a classic RS-232 port on the TH-D7) 
is now a mini-USB port like the ones on many cell phones and Garmin car GPS 
units.  Actually it is a serial port internally, converted to USB with a chip 
similar to the ones on the typical USB<-->serial adapter cable "dongles".  The 
only difference is that (like many current "USB" GPS devices) the conversion is 
inside the device instead of in a cable.

Like the usual dongles, you install a driver in the Windows PC to convert the 
USB connection back to a virtual COM port so that  serial-port-oriented  APRS 
apps and radio programming utilities can still "think" they are using a serial 

However, for some reason, Kenwood didn't use the common Prolific or FDTI 
USB<-->serial conversion chips widely used in  other USB<-->serial cables or 
devices such as the TNC-X, the Pfranc USB<-->serial cable, Pharos/Microsoft GPS 
units, etc. If you have ever used one of these devices, you probably already 
have the drivers for one or the other of these two chips already on your system.

Instead, Kenwood opted to go with the far less common Silicon Labs CP210x USB 
to UART Bridge chip, resulting in the need to install yet another 
USB<-->Virtual Com Port driver.   Details here:


3)   Antenna fitting is a GIANT STEP BACKWARDS from the pain-in-the-neck SMA 
connector on the TH-D7.  The stubby antenna (a.k.a. a badly-shielded dummy 
load) has a threaded FEMALE fitting on it's bottom that screws down onto a MALE 
threaded stud recessed in the antenna connector on the radio chassis.  Looks 
like a (no doubt metric) equivalent of a #8 or #10 screw.    Lotsa luck trying 
to adapt an external antenna with coax to this thing.

4)    Radio has built-in GPS, but the the classic 2.5mm stereo mini-jack for an 
external SERIAL GPS remains.  This allows you to continue to use RS-232 serial 
GPS devices like the GeoSat AV-5 mapping GPS as both a GPS source and display.  
The GPS port can also accept certain Peet Bros or Davis weather stations as input.

The TH-D72 has a "GPS-only" mode with the radio part turned off, that allows 
you to use the unit like a hand-held GPS (such as a Garmin eTrex) with track 
log and waypoints for extended periods.    Specs say GPS-only battery drain is 
only 60mA.

An feature of the built-in GPS log is to the ability to only record the points 
that were also beaconed over RF.  This could have some interesting uses in 
evaluating APRS coverage, by comparing the points logged locally with the 
points that made it to the APRS-IS after an outing.

5)    The optional battery pack holds 6 AAA-sized batteries (not AAs) !!  
Outrageous since you pay about the same for AAs and AAAs, but get at least 
twice the energy in a AA.....    [Hoping Batteries America quickly comes out 
with a third-party pack for AAs.]

6)    The TH-D72 supports both proportional pathing (more frequent beacons on 
short paths and less frequent beacons on longer paths),   --AND-- smart beaconing

7)    The currrent Kenwood "Memory Control Program" being offered for this 
radio is the MCP-4A software intended for the non-APRS predecessor radio.    
You can edit memory frequencies, PL codes, etc, but there is NO support for any 
of  the APRS features in the memory config program (unlike the software for the 

8)    Didn't anyone in the Kenwood USA organization proof-read this 
manual??????    The manual is full of  mangled Japanese "Ingris" such as these:

 From page GPS-3 in the large PDF:

"Battery Saver (GPS Save)

  This function will turn the GPS power source Off
after the programmed timer expires if position data
is not determined during the maximum catching time
(approximately 5 minutes). To prevent unnecessary
battery consumption, when there are many reception
satellites, the GPS is stabilized and position data can
be determined, the GPS power source repeatedly turns
On and Off."

 From page PACKET-1:


Connect this transceiver to your personal computer via a Terminal Node 
Controller (TNC).

Huh??   A radio with a built-in TNC needs another TNC to connect to a computer??!

[I assume that what they really meant to say was "Connect this transceiver to 
your radio via the built-in TNC"]

On page APRS-15 of the large PDF, train symbol is labeled  "REILROAD ENGIN"



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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