Sunday, March 29, 2009

Mobile Radio

I'm thinking about buying a new mobile radio. I owned several mobile radios in the past. I probably started out with the Kenwood TM-741A. This radio came standard with the 2-meter and 70-cm bands. I added a 220-MHz band unit to it, because at that time I lived in Dayton, Ohio, and 220-Mhz activity was fairly common. I never installed that radio in the car, although I operated from the car with it from time to time. I was probably getting the power from the cigarette lighter jack. I had three separate glass-mount antennas on the car for 2-meters, 220-MHz, and 70-cm, plus I had a glass-mount cellular antenna on the car as well. I kept that radio for quite some time, but did not continue to use it. Then sometime after moving to Columbus in 1996, I bought a Kenwood TM-V7A. This was a dual-band radio with a bluish-colored LCD display. I had a friend help me install it. We routed the power from the battery through the firewall to the radio, which we mounted to the bottom of a slide-out ash tray, which I wasn't using anyway. Coax cables to the antennas were routed along the lower door "raceways" or whatever you want to call them. I can't remember but I suspect that the V7A had only one RF output, therefore I was probably using a duplexer to feed energy to the two separate antennas. I traded that car (a 1984 Toyota Corolla) in for a new 2003 Corolla. I have never installed a radio in that car. A half-dozen years or so ago at the Dayton Hamvention, I bought a Kenwood TM-D700A. This is a dual-band radio that features APRS operation. I had ever intention of installing it in the car, but I never got around to it. It stayed in its original box. A couple of years ago I sold it on Ebay for probably 90% of what I paid for it.

Now I currently have a Kenwood TM-D710A and an Icom IC-2820H. The D710A just like the D700A features APRS. The Icom IC-2820H is a dual-band radio and I have the DV chip installed in order to operate D-Star. I'm actually using those radios fairly regularly from the home QTH as base radios.

What I would like to do is buy the new Icom ID-880H to install in my Corolla. The ID-880H is a dual band radio but one band at a time. This radio is also D-Star ready. I don't know how much this radio will cost as it is just starting to be advertised, but I could certainly expect $550 or so. If I do decide to get this radio, I'll probably do it in two phases. In the first phase, I want to buy and install the antenna. That way I can use the antenna with my HT until I replenish my funds. The antenna that I am looking at is the Comet Antenna SBB-97 tri-band antenna. In case you are wondering why I would buy a tri-band antenna for a dual-band radio, the reason is that I am looking to the future. The SBB-97 is a 2m/70cm/23cm antenna. I've considered buying the Icom ID-1 radio. This is a $1,000 radio that is strictly 1.2GHz, but incorporates analog FM and D-Star. On the D-Star side, it has the same DV mode as other D-Star radios. DV is digital voice with low speed data. The ID-1 also has a DD mode which is a high-speed data-only mode. I initially talked myself out of this radio, saying that there is probably no one else in Columbus who operates one, and by checking out, that would appear to be correct. However, I had forgotten that I can still cross-band through the D-Star repeater and talk to those on 2-meters or 70-cm, and with the gateway, I can connect to distant D-Star repeater systems. So I will keep the option of buying the ID-1 open and buy an antenna that is appropriate. Along with the antenna, I will need a mount for it. I'm looking at Comet's trunk lip mount options. These use a short section of small-diameter coax to go past the lip of the trunk and the weather seal. Then they transition to an RG-58 type coax. As a temporary measure I can snake this coax between my fold-down rear seats to a HT that I keep in the front seat. Then I can get the ID-880H as part of the second phase. I'll likely have someone professionally install the power cable to my battery and find the way to breach the firewall. Then I will install the radio myself.

In the first phase, I can simply operate my HT by connecting directly to the antenna's coax. Also, when I buy the ID-880H, I can connect it directly to the coax. However, if I add the ID-1 1.2 GHz radio it looks like I might have to add not only a duplexer but a triplexer. Obviously a duplexer would be required because two radios would be involved, but I cannot find a duplexer that offers one port with 1.2GHz and the other port with 2-m and 70-cm together. I can find a triplexer that splits the signal from the antenna into three ports for 2-m, 70-cm, and 23-cm, but then I would need a duplexer to recombine the 2-m and 70-cm signals back together for the ID-880H. I'm currently only familiar with Comet Antenna's and Diamond's duplexer and triplexer offerings. If you are familiar with another commercial product, let me know.

One final note. Years ago I purchased a notch filter from PAR Electronics that is supposed to notch out 152-MHz where a lot of pager transmitters reside. I remember driving around Columbus with the Kenwood TM-V7A and getting quite a bit of intermod from pagers. Are these pager transmitters still around? I don't see many people wearing pagers these days, since they can send and receive text messages with their cellphones. Also, my last pager, a two-way Motorola pager, operated in the UHF bands if I am not mistaken.


Sunday, March 08, 2009

Two new Icom D-Star radios

I think that I first read about them a couple of weeks ago on someone else's blog. For the most part, information was only available on Icom's Japanese website and had to be translated to English. Now Universal Radio has pages dedicated to each one. The two new radios are the ID-80AD handie-talkie and the ID-880H mobile. I wonder if these will replace the ID-91AD, and ID-800H respectively. We will find out. I also wonder if Kenwood and Yaesu will continue to stay out of the D-Star game. Naturally, I'll be looking at their exhibits at the upcoming Dayton Hamvention.

I'm happy with my Icom IC-92AD HT and my IC-2820H mobile. I have made a few contacts through the Columbus, Ohio W8DIG 2-meter repeater. The W8DIG repeater system, however, is fairly low profile and I have difficulty hitting it from home. It's usually when I am out and about that I make contacts. I am somewhat disappointed in the D-Star network as a whole. One of the prime benefits of D-Star is the ability to interlink D-Star systems. So far, it appears that many systems are not interlinked. I believe that in order to be interlinked, it has to be registered with the Trust Server. W8DIG is not currently registered. It is possible to make a contact on the D-Star repeater and have your information show up on The other problem that I am having is seeing my position information show up. I have the HM-175GPS speaker-mic, and I am fairly confident that I have the radio properly configured for sending the position information so that the APRS network can pick it up, but the IC-92AD is not showing up; only my TM-D710A station. Perhaps it is time to send an email to the W8DIG trustee to see what is going on and offer my assistance.