| VK2BEN |
Rating:      |
2011-09-29 | |
| Great performance & Stealthy! |
Time Owned: 3 to 6 months. |
I bought mine from HRO, along with matching Larsen NMO trunk mount. It fitted quickly and easily to my 2003 Subaru sedan.
This model was chosen for the fact that it is a [loaded] 1/2-wave on 2m; requiring no ground plane. Important point for me, as I am not in a position to drill a hole in my roof for central antenna placement.
This antenna performs very well for me on both bands. It is quite tall (85cm+), which is OK as a trunk-mounted solution. It would be too tall if I were to roof-mount it.
However, even being so tall it is incredibly stealthy! The muted black paint job matches my black car and is very difficult to see against most backgrounds. This means it attracts less of the wrong type of attention.
The centre coil is an integral part of the antenna element; meaning no grub screws to come loose. However, it is worth mentioning that there are grub screws connecting the antenna to the screw-on base section....which then screws onto the matching coil housing at the bottom. Watch that you tighten these sufficiently!
One note on Larsen service: Brilliant.
On the second day of using my antenna, I suddenly could not receive all but the strongest signal. And nobody could hear me very well either.
So, I pulled the antenna off and checked all the connections. The matching coil at the bottom smelled burnt! So I emailed Larsen directly and asked if they would help me directly (rather than spend even more time going thru the retailer) - and they replied very promptly. Apparently, they knew that some components in the matching circuit could be faulty.
Lucky me that I got one of those....being about as far away from the USA as a customer could be!
However, Larsen shipped out a replacement part with FedEx at no cost to me. And the new part has been working fine ever since!
Thanks, Larsen!!
Hope you all have as satisfying an experience with their products as I have.
73,
Ben VK2BEN
Sydney, Australia. |
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| N8DXB |
Rating:      |
2011-04-21 | |
| Great Antenna |
Time Owned: 0 to 3 months. |
| After owning many mobile antennas over the past 30 years, I wanted a good dual band antenna to replace the ΒΌ wave dual band antenna on my truck, and this 2/70 enden up being a excellent performing antenna. It tuned great with a swr under 1.4 on the band edges and 1.1 in the center of the bands. Plus, with it being only 34 inched long with the optional spring added (after tuning); I can leave it on the truck all of the time. It clears my 10 foot garage ceiling by three inchas and it bends over nicely going through my eight foot garage door. I would recommend this antenna to anyone looking for a great dual band antenna. |
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| W4IW |
Rating:      |
2010-08-07 | |
| The ONLY Dual Band Mobile Antenna In My Book |
Time Owned: more than 12 months. |
I bought one of these to replace another brand dual band antenna (either D or C, I'll have to dig out the old bill) which didn't last very long. It was on my personal vehicle and one limb over a highway took it out by ruining the membrane in the tilt-over.
I read the reviews and decided to give this one a try and added the spring kit (I cut off about 3 inches of the antenna, the length of the spring) and mounted it on the roof of a Ford Explorer work truck that is used to service tower sites in Eastern KY. It has been to the highest points in KY in 19 or 20 different counties for more than 3 years and still looks and works like new out of the box.
And work it does, it is a fantastic antenna. It's part of my mobile package that gets rave reports and has for years.
After using this, I wouldn't even try another brand. |
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| KX5F |
Rating:      |
2010-07-18 | |
| Great Antenna |
Time Owned: more than 12 months. |
| I have had several of these, one thing I found out that they are critical to feedline length. One I had I could not get the swr below 2.1 no matter what I did, I added 18" of coax to the feedline and it worked fine. Just my 2cents. Patrick |
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| K0WVM |
Rating:      |
2010-07-17 | |
| 18 Years & still going strong! |
Time Owned: more than 12 months. |
That's right, still punching out like a champ for an equivalent to an adult in human years! I received this antenna as a high school graduation gift in the early summer of 1992 and it operates off the NMO magmount box it originally came with. I have used it on my parents van wherever we traveled and especially on a Thanksgiving road trip from N. Virginia to N. Central WV., before I went into the Air Force in January of 1993. It worked well then traveling through the Appalachian and Blue Ridge Mountains, hitting distant repeaters along the way.
It also sat in use on three previous trunk hoods of vehicles that I have owned in years past (A 1994 Saturn SL1, 1999 Nissan Maxima which was traded in for my XYL to get a 2002 Dodge Durango and a 2000 Chevy Malibu). Now it sits towards the center rear of my 2005 Dodge Grand Caravan, (Malibu traded in for this van) about 6 inches from where the lip of the back hatch and top meet.
I have never had any issues with this antenna. I also unscrew the antenna and clean off the contacts periodically (every couple of years), as I will do this again before the summer is out. I might look at eventually purchasing a Comet SSB-5NMO to put into use and compare these two antennas. The only thing I changed was to cut off the factory PL-259 connector and replace it a sturdier PL-259 connector. But, even for the minimal abuse I have put this thing through as it approaches 20 years of owning it, it has never failed me. Give this antenna a chance before you decide to go with a more expensive option. You might become pleasantly surprised at what you experience. |
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| AJ6B |
Rating:      |
2010-05-12 | |
| Exceller Performer |
Time Owned: 3 to 6 months. |
No reviews in awhile, thought I would drop one in here..
Purchased my Larsen NMO2/70B about 6 months ago and it has been flawless. I like how the Larsen antennas seal on to my vehicle. I have since replaced my Comets all with Larsen just from the way they seal.
I am using the NMO2/70B as there is also the NMO2/70C. From what it looks like, the "B" version has the coil in the base and the "C" version has the coil in the middle of the whip. I chose to get the base loaded version as if anything happends to the whip, you can order replacement parts from Larsen.
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| KI4RGD |
Rating:      |
2009-07-13 | |
| Didn't work on my Jeep. |
Time Owned: 0 to 3 months. |
I have a 2-door Jeep Wrangler, soft-top. My VHF/UHF and HF antennas are mounted on a specialized antenna mount coming off the gate either side of the spare tire. I'm currently running a Diamond 770NMO with great results.
After reading the reviews for this antenna, I thought I would invest in one and try it out. SWR stayed at 3.1 to 3.5 on all VHF freq. My Diamond 770NMO's SWR stays under 2.0 and 1.5 - not bad. I took the Larsen off and plan to send it back, if HRO will let me.
Dont get the wrong idea about this antenna, I'm sure its a hum-dinger like everyone else has reviewed. I'll keep my review # at a 5 becuase I'm sure it would work on a different vehicle. Jeeps are notorious for being difficult in mounting and operating antennas. There isn't much ground to work with. And yes - the tailgate is grounded, along with multiple points underneath, etc.. Since my Diamond 770 is working - I'll stick with it. Whats the saying, "if it ain't broke - don't swap it out." |
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| KC5MO |
Rating:      |
2009-07-05 | |
| Tough and reliable |
Time Owned: more than 12 months. |
| I have had my Larsen NMO 2/70 for 15 years now and have had no problems at all. Tunes up great ( the NMO mound MUST make contact with the under side of the roof ) and it take abuse! I wouldn't expect less from Larsen. |
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| N0XMZ |
Rating:      |
2009-06-26 | |
| I wouldn't buy any other |
Time Owned: more than 12 months. |
| I've been using the open-coil version for almost 3 years and I'm very satisfied with the performance. The only thing I'd change is the set screw as it does corrode over time. |
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| KD4ONT |
Rating:      |
2009-04-17 | |
| Great antenna that's built to last. |
Time Owned: more than 12 months. |
The first 2/70 I bought must be at least 16 years old and still works like a charm! Granted, it's been on 3+ cars during that time, and pretty beaten up by hitting things with it and being buried in the bottom of the trunk for years. I liked it so much I bought a second one (that had been collecting dust on the shelf at my local ham radio shop for a long time) just because it would be nice to have a new back-up one, just in case the old one gave up the ghost someday. On the car it's on now, it's installed on a trunk lip mount on the middle-side of the deck (because my trunk is short, in back of the window the trunk lip slightly curves up so it's not flat there, and the trunk opens past a 90 degree angle so any antenna would hit the window/roof before it's fully open). I know this isn't the best spot to mount it, but considering I go into parking garages almost daily, it'll do for now. The SWR's are practically flat on UHF but VHF, they're not wanting to com down flat when tuning the antenna. They seem to be between 1.5 to 1.7 in the amateur band there. I know, it's not "perfect" but it's in an acceptable range all things considered and with the compromises typical with multiband antennas. I do remember when tuning it last time, it appeared as if the VHF side might benefit from the whip being a little bit longer, but I suspect that would throw the balance between the middle and base coils off too much.
I've compared this antenna to a few others and always seem to come back to the Larsen because of it's quality build, lack of rusting, open air coil, hasn't burnt up with stock radio power, and it performs well for it's size.
I've read literature online about them and it only states that the 2/70 is 1/2 wave center loaded at VHF and collinear on UHF. During my antenna testing recently (with mainly D-Star), I started wondering why some wavelength antennas work better in different areas and surroundings than others (residential, downtown, areas of somewhat dense "RF eating" tree population, highways, fringe repeater areas and simplex). I happened to stumble upon this website which explained things in an easy to understand way for different wavelength antennas: http://www.hamradioindia.org/circuits/radiation_pattern.php
I also shot off an email to Larsen, asking them for more information on this antenna, mainly on what wavelength(s) is the mysterious collinear UHF side of this antenna? Here is my email and the response:
To: Larsen Info
Subject: Technical question about amateur NMO 2/70 antenna
I've been testing your antenna, along with others, with D-Star amateur digital repeaters. The information given on the NMO 2/70 is that it's a dual band, 1/2 wave center loaded on VHF and collinear on UHF. My question is, what wavelengths does the UHF side use? 5/8 over 1/4, 1/2, 5/8 or something else? From what I'm beginning to learn about take-off angles of radiation with antennas, makes me wonder what it could be? If someone could shed some light on this, I'd be very grateful for their help.
Thank you
Here's their response:
Greetings,
Great questions!
The 2/70 is listed as a a UHF collinear and a center loaded VHF.
The loading for VHF comes from the coil placed in the center of the whip. This coil, however, is also designed to phase the top and bottom sections for UHF. Both the top and bottom sections of the whip are 5/8 wavelengths (roughly) at 445 MHz. The base coil helps impedance match both VHF and UHF. This antenna design is very tricky - and picky in terms of mounting because of the narrow tuning characteristics.
It is interesting that you are looking at take-off angles. As you are probably aware - if delving this deep into antenna theory - the ground plane characteristics (such as the vehicle size / shape) combined with the height above earth ground all play into the radiation performance specific to take-off angles and radiation theory. It gets very complicated to look at!
Best regards,
Aaron, KD7PCD
I hope this information and my experience helps out someone now or in the future with this or any other antenna. And like the article above states: "The vertical antennas has its own behaviors in gain, radiation angle, effective aperture etc. But you have to choose for the best antennas for your own purpose. "Whether we buy or build our antennas, we soon find out that is no one 'best' design for all purposes" - ARRL - 1978, Page 623 - Hi."
In closing, my experience with the Larsen NMO 2/70 black, open air coil design, is that this is a worthy and well built antenna for the mobile that's not an eyesore an will last a very long time. I would recommend it to the average person under average usage circumstances; someone who doesn't want to run dual mono band (VHF/UHF) antennas or overseas built antennas. It's not that big and not ugly either ;) |
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