View Full Version : Newly installed Kenwood TM-281 VHF, and, mag mount antenna?

05-14-2019, 04:05 PM
Wow, this part of the forum sure doesn't see much action. Well, just in case anyone's watching, I just finished installing a brand new Kenwood TM-281A, 2M VHF in our '04 Itasca Horizon 36GD with the CAT C-7 330HP. I thought I'd get away with a PulseLarsen Glass mount antenna. I did it that way initially 'cause I used a glass mount antenna on an '04 VW diesel bug with my ICOM IC2000 and, it seemed to work just fine, waaaaaay back then.

So, fast forward a dozen or more years and, we have todays situation. I got the antenna installed and, took the big beast out of its cave for a test. Well, I contacted a friend who, was probably no more than a couple of miles away and, he said I sounded just great, on low power. But, he's got a lot more experience than I do and strongly suggested that I get an SWR reading on my setup. So, I ordered a meter.

Well, I got the meter and, did a test. WOW, NOT GOOD!! My reading is 10:1. So, he came down and we tried a couple of things. In the end, it was determined that I cannot use that glass mount antenna due to the fact that there is some window tinting, built into the glass. Something that my VW bug didn't have. But, while my buddy was there, he had something that he thought he'd try, just for grins. He broke out a mag mount NMO base. On that base is a Diamond NR 72B 14" antenna.

Well, we first did an SWR check with that antenna. 1.4 : 1, Yahoooooo! And, the second check was a transmission/reception. That went just as good as the SWR check. He called a fella about 35 miles away and the conversation was flawless. Now, maybe a 14", magmount antenna is not the best combination but, based on the fact that I've got only about 18" of header to RV roof clearance in our RV garage, it's gonna have to do. I'm not looking to contact Mars or Jupiter, just some other folks while traveling or, maybe while we're camped in some town/city/countryside.

Anyway, that's my latest install, we'll see how well it works, when we travel in a week or so.

Paul Stewart
05-15-2019, 05:03 PM
Looks good. That distance is great and the mag mount is great for mobil. That SWR should make you and your finals very happy. So glad you checked it out.

Paul Stewart
05-15-2019, 05:06 PM
And you are correct. Not only this part but the whole blog us quiet. I keep checking but there is little activity.

05-15-2019, 05:30 PM
Hi, Scott

Yes, the tinting layers in the glass (or on it, sometimes) can preclude through-glass antennas. I've run into that too, on occasion; but one time I thought that was it but when I put my RigExpert Analyzer (AA230 Pro) on it, it was nice and flat, but at 123 MHz! It wasn't mounted on my li'l airplane (1946 Commonwealth Skyranger), so I ground off 1/4 inch at a time until it got near, then 1/8 till it was in the 2M band. Then it worked well for a decade or more.

I think you'll like the TM-281A. It's handy to operate, way sufficient in power, rugged and reliable as a pickaxe, and its gazillion memories can be loaded from a PC. That's handy if you've got more than one (I have six or seven, plus a couple TM-271A which is basically interchangeable with TM-281A and loads with the same software and cable). No, I don't have six or seven vehicles; it's just that I don't have much sense either.

There's one in the motor home, one in the Toyota, one on my little electric scooter, and several in APRS trackers. Great radio, and dirt cheap.

05-16-2019, 12:02 AM
Hey Gang,
I surely thank you for answering me on this part of the forum. While I'm not exactly new to Ham, I have had my Tech ticket now for just over 11 years. I've never really gotten into the hobby. But, lately, it's become a bit more interesting to me. So much so that, I've got my original Yeasu VX-170 VHF handy-talky. A neighbor GAVE me an ICOM IC2000 quite a few years ago and that's the radio I used in my VW bug for a while with the glass mount antenna.

But, lately, as stated, I've gotten a bit more into it. I mounted that ICOM IC2000 in our Jeep and installed an NMO mount VHF antenna on the back. Then, I purchased a Baofeng UV-5R 8 watt handy talky and it's kind of a kick to play around with and it's dual band, for a mere $47.00.

So, since I had that stuff, I figured what the heck, lets put one in the motorhome. So, HRO supplied the Kenwood TM-281 and both my antennas. I didn't purchase the cable and programming software 'cause, I don't mind manually programming any of those radios, other than the Baofeng. It's a pain in the butt to manually program. Since most all of today's radios, be them dual or single band, all have pre-programmed repeater shifts/splits etc., it makes manual programming, a whole lot easier.

05-16-2019, 06:53 PM
I have DC to daylight in my truck 440 down to 80 meters. Now get this my truck bed is composite plastic where is the ground plane? See it does not matter get on the air. (by the way in some thing like a vehicle ground loss is a bigger problem than ground plane) My camper sports a screwdriver antenna it's on a mast just above the roof mounted to the rear bumper I do 80 AM bearfoot yes a whopping 25 watts people still hear me! go have fun that's what it's all about.

06-10-2019, 08:11 PM
Nice. What is the total height to the top of the antenna? I've got a 12' 6" Class A so I'm looking at the 144/440 COMPACtenna because it's only about 7". I'm a bit concerned about bridge-whacking. And I'm sure my wife will not like my "But it's got a spring!" excuse. :)

I'll probably U-bolt a piece of angle aluminum to the top of the ladder and mount the antenna to it. The issue is where to put the radio. While your location would work, it only works when I'm driving and not when my wife is driving. I was thinking of a Lido Mount but bolt it under the center doghouse hold-down bolt.



06-21-2019, 08:33 AM
The stinger is quite long I have a removable clamp for the whip and have to remove it to get into the garage I said bumper on my last post it's not on the bumper it's mounted inside of the truck bed on a standard ball mount then supported a bit higher up on the mast with a homemade lexan insulator. The ideal is to clear the roof line with the coil I have seen a few MH installs with the antenna mounted on the ladder with only the whip above the roof I don't believe that to be very efficient. All of my high freq antennas are mounted edge of the bed of the truck yeah I'm hard to miss looks like a porcupine. I have several photos that I can share.

06-24-2019, 04:57 PM
With a screwdriver antenna a great deal of the antenna is the coil inside not the stinger.

09-05-2020, 08:17 AM
I also have a Kenwood TM-281. But I'm less than impressed with its features. I have a Yaesu dual-band in my truck which allows direct frequency input from the mic by simply punching in the numbers. To do that with this unit, I have to change the function of one of the mic buttons by programming it, and then to input a freq you punch a VFO button, enter the six numbers, then punch the button you earlier programmed. This is a laborious and potentially unsafe process for a mobile radio .... not really "mobile" if you have to pull over and stop to do it. I also find the mic to be quite heavy and much bulkier than my Yaesu, yet the labels/numbers on the buttons are very tiny and difficult to read. Transmit/Receive capabilities are fine, no complaints. The radio has a scan feature which allows to scan a band, a single MHz, or the channels programmed into memory and that's pretty cool.
Installation was very easy and quick.

09-06-2020, 02:32 PM
The TM-281 Kenwood is not a high-end or multi-frequency radio. It's just a great single frequency, somewhat easy to use radio. I installed mine in the motorhome and, it works great in there for primarily basic communication between other RV'ers (with HAM capabilities) and the wife when she's running point.

01-22-2021, 10:23 PM
Has anyone used one of those "window-mount" vhf/uhf antennas (e.g.: MFJ1734) on a Tellaro class B van ?
How is it working ?
I am hesitant because those windows are also tinted so I don't know how lossy (and/or reactive) the capacitive coupling system would be