Posted on
by

Kenwood TH-D72Since early 2012 I do my daily commute by bike. It’s a 18 kilometers (11 miles) one way so I have a little 50 minutes to kill per ride. Mischa PA1OKZ, manager of the local repeater PI2NOS started an experiment earlier this year connecting more then one receiver to the repeater. The second receiver is located nearby my destination (work). When I read about this I figured if I take my hand-held, maybe I could work PI2NOS the whole ride! So time to dust of my Baofeng UV-B5 and take it with me for my daily commute. It turns out to work splendid! My Baofeng itself isn’t suitable for everyday use. It’s battery hold out for only one ride. The battery lips on the back seem to hold current, it tickles in my sweaty hands. And the most annoying: the transmit-button is small and is hard to hold when biking.
It seems I have to search for a better hand-held, probably non-Chinese. I’m a bit of a Kenwood-fanboy (I just really really really like their products), I start looking for a hand-held from Kenwood. Their flagship is the TH-D72. A dual band for 2m and 70cm and is also APRS- and GPS-enabled due to the build in TNC. The price is quite hefty (around 475 euro’s) but if for daily use I probably shouldn’t scrimp on quality. I try to do my hobby budget-neutral so I had to sell something before I buy something new. For this amount of money I had to sell half my shack. Biggest item to sell was my beloved Kenwood PS-53 power supply. When the amount was reached I send out an email to my favorite store: HAM-shop from Marcus PA2DB. Two weeks later my package arrived! I use my new Kenwood-relative TH-D72 everyday. It is a great piece of ingenuity! I still have to find a good spot to put the hand-held when biking. When it is dry weather I click it on the sling of my backpack (on top of my shoulder). But when it rains I put it in my backpack. Then it’s harder to work the repeater on low power. APRS and GPS work great but they also suck a lot of battery power. When put on both and running high power (5 watts) the battery only last two rides (back and forth). So I’m still experimenting with settings to enjoy the longest battery-life and put on the most options.

Posted on
by

GPS logoI did use a bluetooth GPS-mouse with my TM-D710E to send out APRS-packets before. That configuration needs a bluetooth receiver module to convert the data-stream. I don’t like extra boxes especially not in the car (that is where I also use my TM-D710E). So I keep searching for a more compact solution. In the meantime the Kenwood TM-D710G was introduced. But I didn’t had 650 euro for a new radio. The TM-D710G has a GPS-receiver in the head unit. A great idea, maybe it is possible to build such a receiver in my TM-D710E. After googling around a few times I found this Swedish site.
A great solution and exactly what I was looking for. The GPS-receiver in this mod uses plain RS-232-level signals so there’s no need for TTL-RS232-converters as in other mods. Erik Sohlén from the site could send my this GPS-receiver for only 38 euro. I ordered the mod and a few weeks later it arrived. Only three wires need to be installed and the GPS-receiver has to be glued in.
The mod works excellent! The GPS-receiver only starts its data-stream when it has a satellite fix. So when the receiver hasn’t a fix yet, the GPS-sign on the TM-D710 isn’t blinking. That way you can check if there is a fix without seeing the GPS-receiver itself.

Now I’m pretty good track-able via aprs.fi. When I using my car (not everyday) I build in my TM-D710 and set all APRS-settings for mobile use according to Bob Bruninga, WB4APR.

Posted on
by

Replacement fan for TM-D710In the first months after I bought my TM-D710 the original fan starts making a screaming noise when I put on the radio. After about one minute it seems like it gain enough traction and became a bit less noisy, and only turns on when I transmit. Since I use my TM-D710 in my home office primarily , it still is too loud.
Recently I subscribed to a Yahoogroup for the Kenwood TM-D710/V71. One of the threads that popped in my mailbox was one about changing the stock fan for a more silent one. I ordered the SilenX Ixtrema IXP-11-14 from Freezing Hardware for a whopping 14 euro’s.
The old fan was out in a breeze, the new one in place in a minute. Only thing I had to do was change the original connector. Since all three wires of the SilenX are silver, it was a bit of gamble which one to pick. When I connected the radio for a test run I came to the conclusion I used the wrong wires. No sound of a running fan at all. Not even when I was transmitting. Fortunately I did put my hand in front of the fan before rewiring it and noticed that it did suck air in. When I took a good look, it turns out the fan was running, but without noticeable sound! Unbelievable what a difference! Now I can listen to the local repeater at the lowest volume without a screaming fan every time APRS push out a packet.

I also use my TM-D710 in the car from time to time. Of course the fan noise is not a big problem in the car where other noises are more dominant. But less noise in the car isn’t a bad thing at all.

Impression of the modification: