The Kenwood TH-D7 Data HT
The worlds Ultimate HT
Darryl Smith, VK2TDS
(August 1999)
Ever Imagined a radio that has everything that you could ever
want built in? How much simpler life would be. But what is everything. I
guess I would start with a dual band 2m/70cm radio.
Then I would add a TNC - how hard can that be in this age of computers.
1200 bps is boring, so I would go for 9600 too. And then I would
want a built in battery so I could work without power. To aid mobility
make this into a HT. A bit far fetched? Well those are the specs
of the new Kenwood Handheld.
I knew all about this radio well before I received it. I had a copy of the
instruction manual. Friends told me what they thought of this radio. But
nothing had actually prepared me for seeing this radio in real life. I had
no concept of how small it was going to be. Kenwood had pushed so much
into this radio that I thought it would need to be quite large,
at least the size of my old 15 year old 2m HT. But this is far
from the truth. This radio is smaller than many cellular phones.
It certainly would look like one, were it not for its 12 inch antenna.
The radio operates on 2M and 70cm with two independent transceivers.
Both transceivers are dual band - one operating on
2M and 70cm, and the other operating on 2M and receiving on the 118-136MHz
aircraft band on AM and FM. The radio is comes with all the normal
features but don't expect to
find the squelch control without reading the manual. The squelch control
is set by pressing buttons rather than with adjusting a knob. While there
is a knob for volume control, it is hidden below the tuning knob.
Most of this radio is controlled by a central set of 4
cursor keys. The cursor keys along with the 3 line 8 character display
make using this radio as simple as possible. Gone are the days
of remembering secret memories for settings. On this
radio, all the options are in a hierarchical menu that can be simply
navigated as simply as using the cursor keys in Microsoft Excel to
move round a document.
I am still getting used to using this radio. I have only needed to go
to the manual for the major items, such as how to turn on the TNC, and how
to wire up the cables. Apart from that operating the radio is a piece of
Cake. I am not saying that you should not read the manual. In the case
of this radio the manual will tell you a lot about the radio and how
it works. 90% of the time you will not need any information
from the manual. But when you need the manual, you need it real bad.
People that hate mice, and cursor keys will hate this radio. On the front
of this radio, Kenwood have placed an cursor device used to change
frequencies and enter information. Once you get used to how it works, it
is surprisingly quick to use. The keypad is not suitable for people with
long nails or big fingers.
The numbers on the numeric keypad are quite hard to read at times. It is
almost as if the numbers are an afterthought. I find myself
just remembering where the numbers are. It works better that way. Besides,
with 200 memories you do not need to enter numbers very often.
The antenna connector is unlike any I have seen on any HT to date. For
some reason Kenwood chose a [SMA] connector for the antenna. This is
an interesting choice being a deviation from the more normal BNC
connector. Adapters are available, but not cheap. The antenna itself
is a tiny bit too rubbery. Friends have reported far better results with
an after market antenna of a similar size.
I can just see myself working on a WICEN event with the D7A clipped to
my belt, probably behind me, with
an extension mic for VOICE communications, holding the GPS
receiver showing me where the other stations are..
On the Air
One of the first tests of this radio was with David Byrnes, VK2XMF and
myself round Hyde Park in the centre
of Sydney. David purchased his radio the same
time I purchased mine. For the first test he hooked our D7E's up
to our GPS recievers. David uses a Magellan and I use a Garmin GPS-12.
We set up the handhelds to transmit our positions every few seconds on VHF
whilst we talked on UHF. As we walked around Hyde Park, the D7E would kept
track of where the other handheld was, and displayed it's position on it's
LCD display. Not bad, but then I looed at my GPS receiver - the D7A had
told the GPS where David was and plotted his position on my GPS receiver
next to his callsign.
During the ANZAC Day long weekend, David organised a real test for the
reciever. David took the D7E camping in the Blue Mountains west of Sydney.
During his hiking, we was always within range of the VK2WI BBS system. For
the weekend, David had VK2WI digi-peat all his position reports to the
APRS community round Sydney, and thanks to an Internet Gateway, to the
world.
This weekend, David also tested one of the other features of
this radio - The ability to send Internet Email from the radio with
no other equipment needed. David was able to enter the single line email
message from the keypad of the D7E. The D7E then sent it
to VK2WI which broadcast the position to the world - or at least
what parts of the world can hear the VK2WI BBS transmissions. My
base station was connected to the Internet for the whole weekend as a test
of APRS. When my station heard the message, WinAPRS worked out that it was
an Email Message, and sent it to the email address listed in the
message. When it was sent, WinAPRS sent a message to David saying that his
email had been sent.
Still, I do not know if I would take a $800+ dollar HT with my hiking
in the bush. I would at least buy a waterproof bag to put it in. For those
that are wanting to protect their radio, kenwood have now released leather
HT case similar to the ones found on mobile phones. The antenna connector
is an SMA connector rather than the normal BNC. As such this radio
shares more with cellular phones that it's size.
I took the radio for a walk around Sydney City a few days ago. The radio
appears to handle pager interference a bit better than my Standard HT.
Even in a noisy street I was able to work out when the squelch
on the radio opened - Not by the sound, but by the feel.
TNC
The modem is actually a 1200/9600 bps modem. Unlike the radio, it will
only operate on a single band at a time, and will not work full duplex.
This is a problem only if you are excited about working some
of the PacSats from your HT. Otherwise it is no great issue.
Anyone interested in a computer controlled scanner could do worse than
look at this radio. It is fully computer controllable, down to the point
of determining the received signal strength on both channels.
The TNC is slightly under featured. The TNC does not keep it's
memory settings apart from callsign when it is powered off. Also, it
cannot keep more than one packet in memory waiting to send it. If you were
wanting to use the TNC as a digi-peater then you can forget it. Because of
the memory constraints the digipeater capability of this radio has
been disabled.
The TNC has the KISS protocol built in, but this is kenwood version of the
protocol that has not appeared to be documented anywhere. The manual lists
some of the commands recognised by the built in TNC. The documentation
assumes that the user is familiar with TNC commands. Without this
knowledge, the manual will be little help. Some of this can be traced to
firmware upgrades after the manual was printed.
What really surprised me though was when I was listening
to the local BBS channels, and the radio suddenly displayed the position
of John VK2TJE on it's LCD display. Apparently the D7E had heard
John's Packet Beacon Text and plotted where he was.
At the same time, it displayed John's callsign on the LCD of the
radio, asking if I wanted to know where he was. The radio even told me how
far away he was.
Functions
Gone is the conventional power switch to turn this
unit on. Being microprocessor controlled, it has a
pushbutton power switch.
The battery in this radio is a bit under sized - the D7A model released in
the USA has 25% (Check this figure) more capacity. I do not
know why Kenwood did not place the larger battery on this radio. The
increase in weight would have been only 40 Grams. The smaller battery is
only 6V compared to 9.6V for the battery on the TH-D7A. This actually
halves the transmit power. So rather than getting 5 watts output, we
only get 2.5 Watts. The 9.6V battery is available for about $150
from kenwood dealers.
The radio takes an age to recharge from a plug pack. According to the
manual a drop in charger is available for the radio, able to
recharge the unit in only about one hour. I would recommend owners
purchase themselves a fast charger for this radio. 16 hours to
charge the battery from the power adapter is a bit long. With a
fast charger it takes about an hour to charge the battery.
Software Control
This radio is powerful. There are something like 200
frequencies, several different VCO ranges, options for power for
VCO's, etc etc etc. Since the D7E is a Data Radio, Kenwood have released a
piece of software to allow users to save their profiles on their PC. Not
only that, they can edit the profile and update their friends radios
too. Kenwood according to their Web site will be eventually selling this
software with the serial cable, but at the moment it is free. It is in
beta testing, but works well.
There is also some shareware software available to control this radio,
giving functionality similar to WinRadio. Every function of this radio can
be controlled over the
serial port, including the PTT button. I would guess that this
function alone would make this radio quite valuble to many
disabled amateurs. The protocol for controling the radio is now even
available on the Internet.
Comparisons between models
Kenwood placed a recall on the USA version of this radio a few
months ago because it would not recognise
some GPS receivers (most notably a popular receiver that
is totally unavailable in Australia because it is bundled with USA
maps). The delay in bringing the radio to Australia has allowed the rest
of the world to get these problems fixed. Unlike much modern
machinery, the D7E is not field upgradable. In fact, it is not
even upgradable by most authorised service centers. In the USA, only one
of Kenwood's national service centres is able to upgrade the software in
these radios. The next version of these radios will have to be field
upgradable if the product is to survive in the marketplace.
As far as I can tell, the only difference between the model released
in Australia and the USA version is the configuration at time of
manufacture. This radio is actually more like a TH-D7A than the
European TH-D7E. The features are those of the D7A with the exception of
remote control and SkyCommand II which have been removed. The only feature
that the Australian version shares with the European version is the
standard UHF frequency range of 430-439.995 MHz.
There is one question that I know everyone is wanting to know - What is
this radio like inside? With any luck the editor has will open
up his radio and take some photos for publication. I can tell you though
that there is a lot in this radio. Believe me when I tell you there are no
user serviceable parts inside.
What is this unit missing. The most major problem is the lack of a charger
for the radio. The instruction manual listed the radio as coming
with a charger, but none was supplied. David
also was missing the charger with his unit. The radio comes with a lead to
attach to a GPS or to a PC, but they only provided one lead. There was
also no connector to plug into the PC. Kenwood are now selling a
serial cable for this radio, but at close to $100 with software, it
is a bit too expensive.
Conclusion.
The Kenwood TH-D7E is an amazing radio. It is one of the most advanced
FM radios to come out for a long time. It is compact at around the size of
an average HT, but packs more into that package than any other radio
on the market. If this is anything like the radios
that the other manufacturers are going to bring out in the next year or
two, I can hardly wait. The younger generation of hams will really love
this radio. It has just about everything they could ever ask for.
The ultimate question is 'Would I buy this radio'? The answer is YES. I
paid for this radio just like the rest of the Amateur community. At just
over $800, it is certainly not cheap. It is about $200 more expensive than
other dual band HT's. But given what is built into this unit it certainly
is good value for money.
Specifications
The unit has two transcievers built in.
Receive Transmit
A 136.000-173.995 MHz 144-147.995 MHz
118.000-135.995 MHz AM/FM -
B 400.000- 479.975 Mhz 430.000- 439.975 MHz
144.000-147.995 MHz 144.000-147.995 MHz
Sensitivity (12db SINAD) 0.18 uV or less (0.28 uV or
less for the VHF sub-Band)
Power Output
13.8V 6W VHF 5.5W UHF
9.6V High Approx 5W
6V High 2.5W VHF 2.2W UHF
6V Low Power Approx 0.5W
6V Ultra Low Power Approx 0.5 mW
Power Consumption
Receive - No Signals 90mA
Battery Saver On 25mA
TNC On 115mA
Weight
340 grams including battery
APRS was referred to a number of times during this article.
More information can be obtained by looking on the
Internet or emailing me.
____
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Copyright © 1994-2005
Radioactive Networks ,
darryl@radio-active.net.au
This page was last updated 2005-09-01 09:15:52
This page was last compiled 2005-11-15 19:12:51
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