Kenwood’s TH-D7A

The TH-D74A is Kenwood’s latest portable HT. Announced in Ohio earlier this year (2016), this handheld radio has recently become available to the US retail market.

This is not your typical handi-talkie. This is a feature packed HT with the inclusion of GPS, APRS, D-Star, HF RX, a KISS TNC, and many other useful capabilities.

This radio has general TX capabilities for 2m, 1.25m, and 70cm along with dual VCO extended RX  and RX modes across those bands including HF starting at 100KHz.

TX modes include FM, NFM, and DV (digital voice). RX modes include FM, AFSK/FM,  Data FSK, AM, SSB, and CW.

Interface a computer to the TH-D74’s integrated KISS TNC (microUSB) and all sorts of interesting digital mode communication possibilities open-up.

Transreflective TFT LCD Display

Kenwood’s TH-D74A is equipped with a trans-reflective TFT color display. A trans-reflective display reflects light in high ambient light conditions while providing for illumination under low light conditions.

The illumination consumes power and, as such, the handheld can be configured to turn-off the illumination after a certain amount of time. The display will re-illuminate when activity is detected on one of the bands or when the user depresses a key.

It does not appear that this handheld is able to dynamically adjust the illumination by detecting the ambient light conditions, a feature common today with devices that are used both indoors and outdoors. Although, the display illumination brightness can be manually adjusted through the programming menus.

The resolution is quite high relative to other handheld radios allowing the user to view and monitor two receive bands at the same time along with a variety of status indicators.

For an amateur radio handheld, this is a very nice display indeed. The display is very easy to read under a variety of lighting conditions.

Gremlins

The TH-D74A performs the majority of it’s functions flawlessly but there are a couple of gremlins lurking, which may (or may not) just be my unit, including:

  1. The device “randomly” performs a warm reset when radio is in dual-band mode and APRS (band-B) initiates a TX beacon. There was a similar issue reported when using D-Star. This particular issue does not appear to be resolved with the 1.04E firmware update on my unit.
  2. TX on band-A while band-B in APRS high or medium power mode causes the display to blank. Possible power-draw issue?

These problems may be resolved in future firmware updates or it could simply be something funky with my unit. Also, I have this radio running full bore with dual RX bands along with GPS, APRS beacons, and RX on the digital modes. Apparently, this is enough to make the digital gremlins grumpy.

And, it’s interesting to note that even though this radio is available in the US right now, the D74A is conspicuously missing from their product line-up on the Kenwood USA website (12-7-2016). Soft launch, Kenwood? Or, something more sinister?

Update (1/4/2017): Kenwood’s recent firmware update (1.05) appears to address the issue where the device would randomly reset with APRS beacons enabled on band B. The display blank issue also appears to have been resolved. Both of these issues were frustrating and the fact that they have been addressed with a firmware update is great news. Also, Kenwood now lists the D74A on the US website, http://www.kenwood.com/usa/com/amateur/th-d74a/

GPS and APRS

Kenwood’s TH-D74A has a built in GPS reciever. Combine that with the APRS feature and you have a powerful combination.

The built-in GPS receiver allows the user to determine their current location along with the ability to track GPS coordinates over a period of time. This would be great for a biking expedition, backwoods hiking, emergency coordination, you name it.

Combine your location from the GPS receiver with APRS and you, your team, and perhaps your significant other can track your location on Google maps simply by visiting aprs.fi In fact, you can monitor and log your tracking information over a period of hours, days, and even years if you so choose.

Unfortunately, being a public service, anyone or any entity (.gov) could track you as well. For those that are concerned about the security aspects of tracking information, the transmitted GPS information can be obscured by setting GPS ambiguity on the radio. This ensures that your precise location is never transmitted. Not to mention, you could just turn it off at anytime.

The APRS feature allows you to also view and monitor data from other APRS stations heard by the radio. This also includes displaying weather information from locally enabled enabled weather stations.

Another significant aspect of the GPS/APRS combination, the distance to other APRS stations that are transmitting GPS information is easily determined. This allows you to determine if a voice capable stations is likely to be within simplex range. Add APRS voice alert and you can receive QSY information for the nearby station for either simplex or local repeater communication. You want to speak with the station? The radio can be set to automatically program the frequency and CTSSS information received from APRS voice alert. That’s handy.


Pricey, but worth it

From a price point and capability perspective, this is not an entry level radio. Although with the number of features it provides and making the assumption that Kenwood will be fixing any early production glitches, I find that the TH-D74A is worth the price-tag. One feature being the built in GPS with APRS. No more dongles, hacked interfaces, and wires everywhere.

Overall, I am happy with the capabilities of this portable. With so many features, it’ll be some time before I can try them all out. I’m hopeful that any remaining issues are solved soon.

This HT will give you a boat-load of things to try-out. Let’s hope that you’ll have some free time on your hands…

Here is a presentation slide-deck from a recent Billerica Amateur Radio Society (BARS) meeting: Kenwood_TH_D74A_Presentation_Slidedeck

 

Author: Jay Vicory

Jay Vicory (AI1EE) is an electrical engineer and computer scientist that has been designing and building embedded systems over the past twenty years. He is an active technology enthusiast and resides near Boston with his loving wife Nina.