mobile antenna

[Patrol9504]

Hi guys

I have a question about what would be a good mobile antenna. I have posted earlier on another thread called "some help". I have two antennas. One is a tram ~144-170 and the smaller one is a laird~440-570...i know the start freq but not the ending to well. Anyway i was told that it was best to get a dual antenna (please keep in mind that i am brand new to ham and i still need to take my test but want to prepare myself before hand. Like being prepared. Also i will be attending a ham meeting in February so please bare with me until then) but as i was saying...i was told to not get a diplexer to connect both. the radio i have in mind is a Beofeng...its cheap and good for a start and i think the powers are 2 and 5. But do i really need a high gain antenna for the vhf/uhf ham bands. I was looking at diamond which has a gain of 3.8/6dbi but they are expensive and they might break with highway speeds. My tram and laird are more flexible and both companies sell dualband antennas with lower gain 2/5 . Should i go for those? I live in a suburban area if that helps and there are many repeaters around

Thanks you
Christa S.

 

[n5ims]

First off, you should limit your search to NMO mount antennas (not much of a limit, there are literally hundreds of quality NMO mount antennas on the market). It's basically the standard type of mount for VHF and UHF antennas. They make them in standard 3/4" hole mount, trunk-lip mount, mag mount, and "L bracket" mount (instead of a single large 3/4" hole on the top of your vehicle, there's only 2 or 3 small screw holes inside your trunk or hood). If you go with something other than NMO, you'll probably be stuck with changing the mount when you change antennas, which is way too much work for what you get) as well as limiting your antenna choice to a very few options if you can keep the mount at all.

I like the Larsen NMO 2/70 series of antennas. They'll handle your power levels (even if you upgrade to a mobile radio that puts out 50+ watts) and allow you to select the size and gain levels you want.

The NMO 2/70 short (http://www.theantennafarm.com/catalog/larsen-nmo2-70sh-1715.html) has limited gain, but is about as short as you'll find for dual-band antennas that perform (those "low-profile" antennas are small, but generally perform poorly).

The NMO 2/70 B (http://www.theantennafarm.com/catalog/larsen-nmo2-70b-1712.html) looks like an oversized cell phone antenna (folks will often think it's just a high-performance cell phone antenna) that has good gain, but is a bit longer. It'll fit just fine on the fenders, but may cause issues with garages if mounted on the hood.

There's also the NMO 150/450C (http://www.theantennafarm.com/catalog/larsen-nmo150450c-865.html) which is the commercial version of the ham 2/70B, but instead of an open coil, it has an enclosed coil. It would be better if you use commercial frequencies since it's tuned for them instead of the ham frequencies.

One nice thing about using NMO mount antennas is that you can swap them out quickly and easily as your needs change. I have all 3 of these dual band antennas and swap them out as needed (use the shorter ones when I'm likely to park in garages and use the longer ones when garage height isn't going to be an issue). I also swap for my single band VHF-Hi gain antenna on trips when UHF coverage isn't necessary and I may need the extra range.

 

[cpfinlay]

Here's my 2c:


Diamond mobile antennas will not "break" due to wind generated by highway speeds; even into into a headwind.

Antennas that flex too much can cause chopping of the signal ("picket fencing").

Gain antennas can sometimes be counter-productive, depending on the terrain and location of the repeater(s), because the gain is achieved by the compression of the radiation lobes.

Read about the difference between ground and ground plane. Some antennas are made not to need a counterpoise (ground plane), but most require one to work as designed.

 

[Patrol9504]

First off, you should limit your search to NMO mount antennas (not much of a limit, there are literally hundreds of quality NMO mount antennas on the market). It's basically the standard type of mount for VHF and UHF antennas. They make them in standard 3/4" hole mount, trunk-lip mount, mag mount, and "L bracket" mount (instead of a single large 3/4" hole on the top of your vehicle, there's only 2 or 3 small screw holes inside your trunk or hood). If you go with something other than NMO, you'll probably be stuck with changing the mount when you change antennas, which is way too much work for what you get) as well as limiting your antenna choice to a very few options if you can keep the mount at all.

I like the Larsen NMO 2/70 series of antennas. They'll handle your power levels (even if you upgrade to a mobile radio that puts out 50+ watts) and allow you to select the size and gain levels you want.

The NMO 2/70 short (http://www.theantennafarm.com/catalog/larsen-nmo2-70sh-1715.html) has limited gain, but is about as short as you'll find for dual-band antennas that perform (those "low-profile" antennas are small, but generally perform poorly).

The NMO 2/70 B (http://www.theantennafarm.com/catalog/larsen-nmo2-70b-1712.html) looks like an oversized cell phone antenna (folks will often think it's just a high-performance cell phone antenna) that has good gain, but is a bit longer. It'll fit just fine on the fenders, but may cause issues with garages if mounted on the hood.

There's also the NMO 150/450C (http://www.theantennafarm.com/catalog/larsen-nmo150450c-865.html) which is the commercial version of the ham 2/70B, but instead of an open coil, it has an enclosed coil. It would be better if you use commercial frequencies since it's tuned for them instead of the ham frequencies.

One nice thing about using NMO mount antennas is that you can swap them out quickly and easily as your needs change. I have all 3 of these dual band antennas and swap them out as needed (use the shorter ones when I'm likely to park in garages and use the longer ones when garage height isn't going to be an issue). I also swap for my single band VHF-Hi gain antenna on trips when UHF coverage isn't necessary and I may need the extra range.

Again forgot to add in one tiny information but those two antennas do have NMO mounts. The little one is on a trunk lid mount nmo and the larger one is on a perminent nmo mount on my trunk too. I don't think many people use uhf in my area. My scanner picks more of them up on vhf. Gotta keep scanning. Thanks for the info though. It all helps

 

[Patrol9504]

Here's my 2c:


Diamond mobile antennas will not "break" due to wind generated by highway speeds; even into into a headwind.

Antennas that flex too much can cause chopping of the signal ("picket fencing").

Gain antennas can sometimes be counter-productive, depending on the terrain and location of the repeater(s), because the gain is achieved by the compression of the radiation lobes.

Read about the difference between ground and ground plane. Some antennas are made not to need a counterpoise (ground plane), but most require one to work as designed.

So maybe having a diamond won't be too bad because it's stiffer therefore i won't lose someone on the other end if i am doing 65 on the freeway. I have an nmo mount on my car and my area can be anywhere to open or to city-like depending where i go. Thanks for the info!

 

[Token]

But do i really need a high gain antenna for the vhf/uhf ham bands. I was looking at diamond which has a gain of 3.8/6dbi but they are expensive and they might break with highway speeds. My tram and laird are more flexible and both companies sell dualband antennas with lower gain 2/5 . Should i go for those? I live in a suburban area if that helps and there are many repeaters around

The gain differences you quote, 3.8 / 6 dBi and 2 / 5 dBi, are very small, you typically cannot hear a difference in signals with such deltas unless you are really on the fringe. More important is the radiation angle of each antenna. Higher gain antennas (typically taller antennas) tend to pull the radiated pattern down a bit more, and so they have a greater effect on paths to stations near the horizon.

If the repeaters in your area are typically on hilltops or tall buildings with significant look up angles (the angle from your transmit location to the receive location) the lower gain antenna will quite likely show better results. But if your comms are simplex vs repeater, or if the region is flat and the look up angles to repeaters is not great, then the higher gain antenna will show increased performance.

As a general statement higher gain mobile antennas are better, but under some circumstances they can actually give worse results.

Diamond mobile antennas will not "break" due to wind generated by highway speeds; even into into a headwind.

Antennas that flex too much can cause chopping of the signal ("picket fencing").

Breaking antennas due to speed is not generally a problem, regardless of brand, at speeds seen on most public roads. But yeah, my Diamonds, Comets, Larsens, MFJs, and for that matter Radio Shack, mobile antennas have never broken due to speed…and they have all seen well over 100 MPH.

Fatigue can cause eventual failure, but that is going to happen regardless of speed. In my experience flexible antennas (say single band base loaded 5/8 waves) show less fatigue related failure. Colliniear antennas have shown the most failure for me, often at the element joints, but that still typically has taken years to show up.

However, mag mount antennas can “break away” (pull the mag mount away from the body) at speed if the magnet is too small. I have had this happen a few times.

Picket fencing has several contributors, but antenna flexing is not a huge factor, regardless of what is said at club meetings . More often this is a result of changing multipath, causing things like phase distortion, and that will happen regardless of if the antenna is flexing or not. Of course if an antenna is bent over far enough this impacts the radiation pattern, and depending on where you are in the pattern it can cause signal issues. Still, I generally prefer flexible antennas when possible, they are less likely to be damaged by impact to tree branches or overhangs.

T!

 

[Patrol9504]

I want to thank you guys for helping me with the antennas. Of course people all have their recommendations. My area can go from anywhere to hills or city to open land. So do you guys recommend both a low gain and a high gain so where ever i am at i can switch over to that antenna?

 

[profiledescent]

Hi guys.........
Anyway i was told that it was best to get a dual antenna......../ ...i was told to not get a diplexer to connect both. ......... I was looking at diamond which has a gain of 3.8/6dbi but they are expensive and they might break with highway speeds. My tram and laird are more flexible and both companies sell dualband antennas with lower gain 2/5 . Should i go for those? I live in a suburban area if that helps and there are many repeaters around

Thanks you
Christa S.

You'll be told what's "best" by a lot of people. Ask yourself if it's what's best for YOU. There are some dual band antennas that are crap, and some that are good.

On the diplexer. Again, not good for who? Best for who? I know many amateurs using them, both to use sepaprate antennas for a dual band, and/or to use two different radios on a dual band antenna. I have used them many times, and haven't had an issue. If someone is quoting you db loss, see what it really amounts to. Two good gain antennas through a diplexer will deliver more signal that a lesser quality dual band antenna. In reading "Gain" figures, "db" means something. If you see "dbi", ignore it, as it's marketing BS.

Break at highway speeds? Not likely. I have a buddy who's a State Trooper. He's never broken an antenna off, and we know he's driven speeds well beyond 100. Even NASCAR was using the thin whip UHF quarter waves for a while, and they did just fine. Sounds like the Diamond NR770 you have. I have had good results from that antenna. If it's the 770, it's a half wave antenna at 2 meters, which is less effected by where it's mounted than others. It's 5/8 over 5/8 on 70cm. It will generate a pretty good wind load to your mount, so plan for that.

Try your various antennas in different configurations and see what results you get. Experimentation is part of the hobby. You'll find guys in the local groups willing to help, teach, and use their SWR analyzers to check thigs out. Oh, and along the way, you'll make some mistakes. It's part of the learning.

Welcome to the hobby.

 

[KC3ECJ]

So do you prefer perm or magnet mounts?

Tram has a dual band magnet mount that gives 0 db gain on VHF, and 2 db on UHF that works pretty well.

 

[Patrol9504]

So do you prefer perm or magnet mounts?

Tram has a dual band magnet mount that gives 0 db gain on VHF, and 2 db on UHF that works pretty well.

Hi
I already have two nmo mounts. One is permanent the other is a trunk lip mount. I already have a laird and tram browning monobands antenna. i was only wondering if i should get two dual band antennas: one with lower gain and another with a much higher gain.

 

[prerunner1982]

I was going to run this antenna (Amazon.com: BROWNING BR-180 Amateur Dual-Band Mobile Antenna: GPS & Navigation ) with my Baofeng UV-5r, but decided to go ahead and get a mobile radio.

Antenna works well, if you don't mind the height of it at 37" tall. It's not all that expensive and would make install cleaner and simpler.

 

[Patrol9504]

I was going to run this antenna (Amazon.com: BROWNING BR-180 Amateur Dual-Band Mobile Antenna: GPS & Navigation ) with my Baofeng UV-5r, but decided to go ahead and get a mobile radio.

Antenna works well, if you don't mind the height of it at 37" tall. It's not all that expensive and would make install cleaner and simpler.

i have a very similar antenna. Browning 150 except that i live in a suburban area where repeaters are a bit more spread out. I was told to get a higher gain antenna. I was thinking of a Baofeng as my first radio though

 

[KG6ABF]

]Diamond SG-7900A (Super Gainer series)

Check out the reviews on this baby. I have been running one of these for quite a while and never found anything short of a Comet GP9 at 20 feet while parked to beat it.

It folds over I use the fold over everyday to park it in a garage. Handles over 100watts input solid construction and it replaced the Larsen and other lesser antennas I used prior to buying and installing this. Checked the VSWR after installing it into a solid mount and on 2 it was about as flat as could be and on 70Centimeters it was flat rising slightly to 1:1.2 at the very top end of the band.
Worth every penny and has been on and off road in every weather condition you run into and works like new.

 

[dave6890]

i have a very similar antenna. Browning 150 except that i live in a suburban area where repeaters are a bit more spread out. I was told to get a higher gain antenna. I was thinking of a Baofeng as my first radio though

If you get a Baofeng, you either will need to buy one of the magnet mount antennas that come with feedline and the SMA connector. Or, if you buy a Tram NMO mount with feedline terminated with a PL-259, you will need to get a SO-239 to SMA jumper. Radioshack should still sell them.

From personal experience:
I set up my Baofeng UV-5R+ with a Tram 1185 NMO dual band antenna with a Tram NMO mirror mount (I have a roof rack and basket that is perfect for mounting antennas). It extended the range by an average of 20 miles. With a Nagoya Na-701 antenna on the HT, I have been able to hit repeaters no farther than 10 miles away. With the standard Rubberduck antenna, the range goes down to less than 6 miles. (all ranges were gauged by contacting different repeaters).

Hope that helps.

 

[dave6890]

Hi guys

I have a question about what would be a good mobile antenna. I have posted earlier on another thread called "some help". I have two antennas. One is a tram ~144-170 and the smaller one is a laird~440-570...i know the start freq but not the ending to well. Anyway i was told that it was best to get a dual antenna (please keep in mind that i am brand new to ham and i still need to take my test but want to prepare myself before hand. Like being prepared. Also i will be attending a ham meeting in February so please bare with me until then) but as i was saying...i was told to not get a diplexer to connect both. the radio i have in mind is a Beofeng...its cheap and good for a start and i think the powers are 2 and 5. But do i really need a high gain antenna for the vhf/uhf ham bands. I was looking at diamond which has a gain of 3.8/6dbi but they are expensive and they might break with highway speeds. My tram and laird are more flexible and both companies sell dualband antennas with lower gain 2/5 . Should i go for those? I live in a suburban area if that helps and there are many repeaters around

Thanks you
Christa S.

What kind of vehicle do you have? I see a bunch of people saying go with NMO and I agree. If you don't want to drill a hole in the roof of your car, there are safer and less destructive mounting options.

I have most of my antennas mounted using this http://www.theantennafarm.com/catalog/tram-1249-connector-choice-1572.html They are mounted to my roof basket.
My Icom 2300H is using this as it's antenna http://www.theantennafarm.com/catalog/laird-technologies-qw144-718.html Believe it or not, it actually isn't too bad. I occasionally drive fast (80-110mph) and have not had any picket fencing with this antenna.

Theantennafarm.com has some good stuff. I get most of my stuff from them or DXEngineering.

 

[KG6ABF]

What kind of vehicle do you have? I see a bunch of people saying go with NMO and I agree. If you don't want to drill a hole in the roof of your car, there are safer and less destructive mounting options.

I have most of my antennas mounted using this http://www.theantennafarm.com/catalog/tram-1249-connector-choice-1572.html They are mounted to my roof basket.
My Icom 2300H is using this as it's antenna http://www.theantennafarm.com/catalog/laird-technologies-qw144-718.html Believe it or not, it actually isn't too bad. I occasionally drive fast (80-110mph) and have not had any picket fencing with this antenna.

Theantennafarm.com has some good stuff. I get most of my stuff from them or DXEngineering.

You can make a 5/8 wave antenna for about $1-2 using a coat hanger wire and an SO-239 connector. then make a mount out of a simple piece of sheet metal and outperform that 1/4 hands down. Of course if you want something that looks better a little work and a couple bucks more you can still beat it and come up with a nice "commercial " looking antenna.

I am not quite sure what you mean by "picket fencing" But if you mean repeater cutting out from signal loss the 5/8 wave will proved better gain and receive. Also proximity to the repeater has a lot to do with the signal.You may be close to it and there for be able to use it with the 1/4 wave but further distances require a better gain in both transmit and receive.

 

[Project25_MASTR]

The great antenna debate. Personally, I run quarter wave on VHF in my dad and wideband UHF knob because I've never noticed a large enough difference to warrant larger antennas. I also run separate radios.

After doing some damage to the roof of my dd, I only run antennas built to commercial specs. If the gain is listed in dBi, you generally won't see me running it (exception with 2.4 GHz).

Stiff versus flexible picket fencing thing really has to do with deflection due to being in a fringe area and not the effect of the Doppler shift due to the whip moving back and forth (which in reality will only shift the frequency up or down about 300 Hz on a 25,000 Hz wide transmission). So more gain would help but it really isn't needs unless your planning on doing a lot of simplex work.