Antenna recommendations for a Kenwood TM-281A

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JDrisc3480

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Hello. I am buying a Kenwood TM-281A to put in a 2019 Dodge Ram. With all the choices out there, I am trying to find an antenna that will work best with a fender mount (wife is not going to let me drill into the roof of the truck).

Thank you
 

mmckenna

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Hello. I am buying a Kenwood TM-281A to put in a 2019 Dodge Ram. With all the choices out there, I am trying to find an antenna that will work best with a fender mount (wife is not going to let me drill into the roof of the truck).

Thank you
Explain to your wife that drilling the hole in the roof will do a lot less damage and look a whole lot better than any compromise mounting.

But, if you must….
There are a couple of things you need to consider when mounting an antenna on the fender like that...
-Generally it's understood that having a transmitting antenna on the same plane as the passenger/driver and in close proximity to the cab isn't a great idea.
-Putting the antenna down below the cab line is going to create some shadowing. You'll have less RF towards the rear of the truck. The cab and the meat sacks sitting in it will be in the way.
-Mounting an antenna off to the edge of the ground plane will cause the antenna to be directional.
-You'll have the antenna and coax next to a lot of noise sources.

If you still must….
Use a half wave VHF antenna with an NMO mount. Skip the hammy/hobby grade antennas, stick with known name brand stuff like Larsen, Laird, Maxrad, etc. Don't buy the cheap knockoff antennas from Tram/Browning. Avoid Diamond/MFJ and the other ham brands.
Use one of these brackets if you want it on the drivers side: https://www.theantennafarm.com/catalog/ram-1500-drivers-side-2019-2020-8906
Or if you want it on her side (remember, you could have had a roof mount…) https://www.theantennafarm.com/catalog/ram-1500-passenger-side-2019-2020-8907
You'll need an NMO mount. But not just any NMO mount. Most NMO mounts are designed to go through the vehicle roof (where God intended mobile antennas to be!), so the underside of the mount is designed to be inside the vehicle, not exposed to the rain/snow/road salts, etc. You should use one of these mounts: https://www.theantennafarm.com/catalog/larsen-nmokhfud-1125
Order it without the connector installed. It'll be much easier to route the cable without the connector in your way. You'll also be able to cut the coaxial cable to length.
Next, get some 5/16 marine grade heat shrink tubing. You'll need 2 inches or so. You can get it at a good boating store (West Marine) or you can get assortments of it at Harbor Freight. Make sure it's the marine grade stuff. The marine grade shrink tubing has a hot melt adhesive inside that flows when the tubing is heated up. That will properly seal the point where the coaxial cable enters the mount. Failing to do that puts you at risk of water getting inside the mount and corroding the crap out of everything in short order.

When you install that, make sure the mounting bracket for the antenna has a good solid electrical connection to the fender.

Route your coaxial cable carefully. One of the drawbacks with that type of mounting is that the coaxial cable can get pinched in the hood. Pinching the coax will change its impedance. It can also damage the outer jacket and let water in. That'll lead to corrosion and all kinds of issues. Route the coax carefully under the hood and keep it away from sharp edges and hot parts. Route it to your radio. Cut it to length, do not coil up the excess cable under the dash. Leave a bit so you can easily install the connector.

I'm running a 1/2 wave VHF antenna on my UTV. It's been beat hard off road, including a number of tree branch strikes. I'd recommend using the same thing:

When your wife complains about it, remind her that you could have a nice short 19 inch quarter wave whip up on the roof where it wouldn't be seen.

(but seriously, I get it. Keep your wife happy)
 

mrweather

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What mmckenna says should really be a sticky on any sub-forum dealing with mobile installations. :)
 

W5lz

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I agree with the 'hole' thingy with a provision or two. If possible, drill the hole. If not, then there are several alternatives depending on how much trouble and expense you want to go to (or have to = Significant Other). A mag-mount is one of those alternatives, but has a few 'things' about their use. After a length of time (no matter what you do) that magnet will wear away some paint. And so will the feed line. Another is that they get stolen, you know? Another alternative is a 'trunk lip'/'hood lip' mount. I've done that fairly often with no particular problems. Don't like that shinny thing sticking out'a the hood? Paint it. (Hot Pink! Why would anyone want to steal that?)
As for what kind of antenna, depends on where you're gonna put it. On the roof? Then I'd suggest a really 'whippy'/springy one, it'll get hit eventually. On the hood/trunk? Same thing really, but a 'stiffer' type of antenna is possible. Unless theres some reason not to have a 'longer' antenna, I would suggest a 5/8 wave (whatever brand you like).
 
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