The Kenwood TH-D7 Data HT
The worlds Ultimate HT
Darryl Smith, VK2TDS
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.
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.
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.
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.
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.
The unit has two transcievers built in.
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)
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
Receive – No Signals 90mA
Battery Saver On 25mA
TNC On 115mA
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.