Kenwood: Confusing TM-281A Programming/Possible Antenna Issues(Mobile)

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Good question.
UHF connectors get to be an issue as you go higher in frequency. While they are called "UHF", it's important to realize that back when they were designed technology was quite a bit different. Back in the 30's, UHF meant something different than it does now.
There's some good info here: UHF connector - Wikipedia

They were never designed to be an antenna mount, only a form of shielded connector for lower frequencies. Mechanically I'd not trust them for any large antenna.

UHF connectors are not, inherently, waterproof, so using them as an antenna mount is not the best option. Ham radio operators are the only ones that seem to like to use them as such. You won't see them used in any modern day public safety install simply because there are better and more reliable choices.

The NMO connectors, on the other hand, were designed from the ground up to be used as an antenna mount. They are good up beyond 1000MHz, and there is even a high frequency version that can be used up to 6GHz. They are waterproof. You can get them for through-hole installs. You can get magnetic mount NMO bases, and you can get bracket mounts, you can even get base station adapters. Just depends on what you want.

There is also a very wide range of antennas that will fit an NMO mount. If you use a UHF mount, you are pretty much stuck with the amateur radio antennas. If you use NMO, you can select antennas that will cover anywhere from the CB radio band well up to 6GHz, including cellular, WiFi, and satellite.

You can use whichever you want, your truck, your radio, your money. If you want the most flexibility and options for different antennas, you'll do better with the NMO mounts.

Thats really good to know, thank you for that! I guess Im back to square one for antenna shopping. Do they even make 1/4 wave 2m antennas with NMO mounts since theyre so lightweight and short? I guess Ill shop around and see.
 

mmckenna

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Thats really good to know, thank you for that! I guess Im back to square one for antenna shopping. Do they even make 1/4 wave 2m antennas with NMO mounts since theyre so lightweight and short? I guess Ill shop around and see.
Not sure I'm fully understanding what you are looking for.

You can buy 2 meter VHF antennas that have an NMO base.
You can buy magnetic NMO mounts that will allow you to attach the NMO base antennas.

We linked to those above. You'd buy an NMO mount VHF antenna that covers the 2 meter band. Here's one for $12.95:
It's just the antenna, you still need to purchase the magnetic base $29.95:

Laird is a reputable brand and makes good stuff. You wont' go wrong with that setup. If you decide to add a dual band radio later on, simply unscrew the antenna from the magnetic base and attach a dual band NMO mount antenna on the original magnetic mount.
 

W5GX

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I appreciate that. Is there a reason I would want to go with an NMO mount over UHF if Im sticking with a magnetic base? I thought NMO was used for drilling holes or using some kind of mounting bracket. Do they swap out easier than a UHF connector equipped antenna and base?
The NMO is the interface for attaching the antenna to a thing - mag mount, vehicle body, etc. The UHF connector is the interface to attach to the radio itself. One antenna "system" will have two connections - the radio and antenna - on either end of the feed line.

NMO is the defacto standard for mounting an antenna, with UHF being a close second - generally for HF antennas. UHF (right or wrong) is the defacto US radio connection standard for all but HT radios which now use various flavors of SMA, moving from BNC.

mmckenna is providing some good info, so I'd just second most of that. I also share his distrust of UHF connectors, mechanically speaking, so I'd also suggest either an NMO or *gasp* solid antenna, similar to the Tram 11861 or even the 1185 (yes - 5/16 connector at the base, but the antenna is light enough). I've used the 11861 for temporary work until I drilled a hole, and it worked well and is a good "just in case" antenna.

As a side note - as suggested earlier, please make sure your new SWR meter will work for VHF (and better, UHF) frequencies. A Workman brand CB SWR will not work in that range.
 
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I definitely plan on going with an NMO mount setup after I get my SWR meter. This is the one I bought:


Im on a budget here and from the videos Ive seen it seems to work well enough. Is it lab quality? No, but it should do ok. Im gonna go with the biggest magnet base I can find. Im looking at the Browning 5.5" magnet base. I am going with a 1/4 wave antenna just to get my mobile rig rolling again, but once I get all the troubleshooting done I plan on getting a 1/2 wave or 5/8 wave as well and swapping between the two depending on where I am.
 

mmckenna

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I definitely plan on going with an NMO mount setup after I get my SWR meter. This is the one I bought:


Im on a budget here and from the videos Ive seen it seems to work well enough. Is it lab quality? No, but it should do ok.
Should be good enough. All the meter does is compare transmitted power to reflected power. While it won't be super accurate, it will give you a good idea if the antenna is tuned well. And if you go with the 1/4 wave VHF, they are really broadband and getting them close is usually pretty easy just using the cutting chart.

Im gonna go with the biggest magnet base I can find. Im looking at the Browning 5.5" magnet base. I am going with a 1/4 wave antenna just to get my mobile rig rolling again, but once I get all the troubleshooting done I plan on getting a 1/2 wave or 5/8 wave as well and swapping between the two depending on where I am.
The Tram/Browning connectors are really cheap. My dad bought a NMO mount from them for his new truck a few years ago. I had to cut off the connector to run the cable, and left the connector on my bench. A few weeks later I found it and dissected it. Very low quality connector. Instead of a proper crimp, it had one center punch style mark to hold the connector on the coax, and then an overmolded plastic cover. If you are really stuck on the Tram/Browning name (same company), then at minimum replace the connector before it gives you trouble.
 
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Should be good enough. All the meter does is compare transmitted power to reflected power. While it won't be super accurate, it will give you a good idea if the antenna is tuned well. And if you go with the 1/4 wave VHF, they are really broadband and getting them close is usually pretty easy just using the cutting chart.



The Tram/Browning connectors are really cheap. My dad bought a NMO mount from them for his new truck a few years ago. I had to cut off the connector to run the cable, and left the connector on my bench. A few weeks later I found it and dissected it. Very low quality connector. Instead of a proper crimp, it had one center punch style mark to hold the connector on the coax, and then an overmolded plastic cover. If you are really stuck on the Tram/Browning name (same company), then at minimum replace the connector before it gives you trouble.
Im not at all loyal to any brand. Every ham I talk to gives me a different answer. Youre saying their junk and the guy at HamRadioOutlet says Browning and Tram are comparable to Laird, Diamond and Comet. Its very confusing.
 

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Comet and Diamond are made in Japan.

Tram, Browning, and RCA are merely brand names. The rightful holder of the brand name has sold the rights to use the name in trade to manufacturers of inexpensive Chinese gear. The guy at HRO is either poorly informed or is just trying to sell you something.

I have some of the Laird GR8 magnet mounts, though I have the black ones. I think they are reasonable quality.

How about this for an SWR meter: https://www.hamradio.com/detail.cfm?pid=H0-009126 It's a little more expensive than the one you listed, but I've never heard of Nissei brand, so I'm a bit skeptical.

Also, don't forget that with your SWR meter, you'll need a short piece of coax with PL-259 (UHF) connectors on both ends to act as a jumper between the radio and the meter.
 

mmckenna

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Im not at all loyal to any brand. Every ham I talk to gives me a different answer. Youre saying their junk and the guy at HamRadioOutlet says Browning and Tram are comparable to Laird, Diamond and Comet. Its very confusing.
Ham Radio Outlet caters to amateur radio operators that are budget minded and using the antennas for hobby use. Having been in the industry for close to 30 years now, I can tell you with 100% confidence that Browning and Tram are in absolutely no way comparable to Laird. HRO is simply attempting to sell you what they have on hand.

I've been to a lot of industry trade shows. I've talked with the antenna manufacturers. Larsen, Laird, etc. are all reputable companies that build their own products and stand behind what they sell. I talked to the Tram/Browning guy and I'm not sure he really understood what he was selling. They are cheap Chinese knock-off antennas. I would never use them in any sort of professional application. I have worked with a few of their products, and I'm not at all impressed. Their 'crimp' on connection for the mounts they sell are pure sloppy junk and the only thing that holds them together is the overmolded plastic.

It's your money, your antenna, you buy what you feel comfortable with. For hobby use, Tram/Browning may be just fine. But they are in now way equal to the name brand stuff.
 

mmckenna

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Ok so this base has caught my eye. I like that it has a rubber base. I guess 90 lbs of pull strength would be enough to stay put when driving with a 1/2 wave antenna, but not a 5/8 wave. I dont see myself driving around at speed with a 5/8 wave antenna anyway.
The difference in length between a 1/2 wave and 5/8 wave antenna is a few inches. It's a thin whip, often near the top it's about 0.1" diameter. The amount of wind load from that is negligible. You won't need a larger magnetic mount for the different antennas.

The benefit to a 1/2 wave antenna is that it does not require a ground plane to work, although it works better with one. With a proper ground plane, a 1/2 wave antenna will have about 2.4dB of gain compared to a 1/4 wave.
The 5/8 wave antennas require a ground plane. It'll have about 3dB of gain compared to a 1/4 wave.
That 0.6dB of gain probably won't be noticeable to you in 99.999% of situations. In fact, some report worse performance from 5/8 wave antennas since they tend to be a bit longer and bend back some more at highway speeds.

After a lot of trial and error, I only use 1/4 wave antennas on my personal vehicles as well as all our VHF mobiles at work.
The only place I use 1/2 wave mobile antennas is in applications where I don't have a sufficient ground plane to make a 1/4 wave work properly.
I think I have one 5/8 wave VHF antenna in my garage left over from about 25 years ago. I don't use it.

It's fun to experiment with different antennas, and what you find may very well be different from what I've found. It will depend on your local topography. In the plains, the 5/8 wave antennas can work a bit better because they achieve their gain by forcing the radiation pattern towards the horizon. In the hills/mountains, you'll often find that 1/4 wave antennas work a bit better since they do not have a compressed radiation pattern and radiate some energy above the horizon where mountain top repeaters are. As always, your milage may vary. It's all part of the hobby, so try out what you want.
 
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Man. This is all great information. Thank you all for your input. The antenna and base is just one step in figuring out whats going on with my mobile radio. That being said I want to do this right. I need something very reliabe that performs well.
 

mmckenna

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That being said I want to do this right. I need something very reliabe that performs well.
Got it. Stick with the Larsen or Laird products.
Good antennas should last you a very long time. Might cost a few bucks more initially, but it really pays off in the long run. Like I said earlier, I have a few Larsen antennas that are near 30 years old and still look and work just fine.
You've got a good radio, pair it up with a good antenna and mount and you'll be happy.
 
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I wish I could show you all pictures of my current antenna connector but Im getting an error message saying that the file is too large fr the servers to upload.
 

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Tram, & Browning are total garbage. The names are just memories of quality made deluxe CB radios in the 60/70’s. My friend wanted a Liard/Antenex TRAB4503 for his truck, but the local vendor didn’t have any. But he did have the Tram/Browning equivalent. Absolute garbage. He ordered the Liard online for double the price, & it was worth every penny. The only people who like the Tram/Browning trash are the ham radio stores who make a good profit selling that crap. Years ago there was a local ham radio store, & he told me while he sold real antennas, he made twice the profit selling Tram/Browning waste for less than the real stuff. Oh, my friend with the useless antenna didnt bother to return it. However it did become a target for his newly acquired AR-15.
 

mmckenna

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However it did become a target for his newly acquired AR-15.
A suitable end.
Some day I'm going to buy one (I'll wear a disguise…) and take the coil apart. I've got some old Laird coils that I could open up also. Would be interesting to see.
 
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Tram, & Browning are total garbage. The names are just memories of quality made deluxe CB radios in the 60/70’s. My friend wanted a Liard/Antenex TRAB4503 for his truck, but the local vendor didn’t have any. But he did have the Tram/Browning equivalent. Absolute garbage. He ordered the Liard online for double the price, & it was worth every penny. The only people who like the Tram/Browning trash are the ham radio stores who make a good profit selling that crap. Years ago there was a local ham radio store, & he told me while he sold real antennas, he made twice the profit selling Tram/Browning waste for less than the real stuff. Oh, my friend with the useless antenna didnt bother to return it. However it did become a target for his newly acquired AR-15.

Ive already purchased a Laird antenna and magnetic base so at least I can remove that from the equation and I can focus on why Im having these issues to begin with. I dont wsnt to get sidetracked too much on the antenna since for the sake of this thread, its merely a means to an end. Thanks for the input. Based on what others have told me I just avoided both brands all together.
 

bobruzzo

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Got a link? If you can get a genuine Laird VHF antenna -and- a genuine Laird NMO magnetic mount with cable and connector for $12.00, I'd love to know. Usually your looking at $30 for the mag mount and $15 or so for the antenna.

Just beware of cheap knock-offs.

There is a big difference between antennas, and if you got your hands on one and held it side by side with the Nagoya, you'd see what I mean. Laird, Larsen and the others stand behind their products. There's a good reason they are the brands you'll see in pubic safety applications. The guys who install this stuff know they can be trusted, and they know they'll last a long time. I've got 30 year old Larsen antennas still working/looking like new. All the old ham grade antennas I had from the late 80's/early 90's are all long since in the trash.
I agree 100%....I am STILL USING my Larsen dual band mobile antenna. Used when I was hamming for 2 meters & UHF. Originally was purchased around 1991-92 used in nmo permanent roof mount. Went thru a few different mounting configs over the years and different vehicles. Antenna is now in middle of my roof on SUV with heavy mag mount base. I swear by Larsen and will only use them.
 
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OK so Ive had a few days with my TM-281 after installing the new Laird NMO antenna(1/4 wave) and magnetic base. SWR reads around 1.3:1 and Im getting around 60 watts out of my transceiver. Im able to RX and TX but very often I am getting loud static for about 2-4 seconds(sometimes more) AFTER I TX and right at the beginning when Im RXing someone on the local repeater. Im never more than 10 miles from the repeater when this happens. Im at full squelch and have adjusted that a bit with no difference. Any ideas where to look or is this normal?
 

AK9R

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You may be picking up some sort of RF noise that the squelch circuit has trouble with. Does it happen on all frequencies or just one?
 
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