K3RRR Yaesu ATAS-120a Mobile, Portable and Fixed Station Antenna
ATAS-120a – Some K3RRR Uses: Portable, Permanent and Mobile
I wrote this highly viewed page a few years ago. I have since sold all of my Yaesu equipment and gone all ICOM.
As a result, I sold my ATAS and have installed a Diamond SD-330 screwdriver antenna with a Tunematic TM-1 controller to work with my dedicated mobile rig: the Icom 7100. I’m still installing more ground bonding in our new SUV and we are now in the depths of the sunspot cycle – but the ATAS seemed to work better.
This is a completely preliminary opinion on my part that is subject to very significant changes as I get more done with the new system installation.
(Since I wrote this update, things have changed again! My Subaru Forster SUV was awarded joint custody along with my Shack for my new ICOM 705 (I sold the 7100 and the Diamond screwdriver to help fund my much loved ICOM 705.) I’m now using the Wolf River Coils Silver Bullet Mini for both portable and mobile operating. It does require manual tuning versus the automation that I had with the Diamond screwdriver – but seems to work at least as well if not better.)
I also wrote this original page prior to owning an MFJ 1786 magnetic loop antenna which I installed at this mountain location as well as our beachfront condo. As with everything in life and Ham radio, each has its own pros and cons.
However, the upshot was that the MFJ loop did significantly better than the ATAS – partly because it was so much less noisy. Your mileage may vary significantly – but you might want to check out my magnetic loop page by clicking MFJ 1786.
Now back to the Yaesu ATAS-120a comments that I wrote a few years ago. I hope you find them helpful! (I kept the following in present tense.)
I use the Yaesu ATAS-120a – a 2 lbs screwdriver-type, autotune antenna that is designed specifically to go with both my FT-897D and FT-857D, for both mobile and portable operations. It does a surprisingly amazing job for both.
Best DX so far: Mobile from the top of the Smokies to VP8, Falkland Islands – with 10 watts – even at the bottom of this sunspot cycle. I have received so many requests for info and photos on the ATAS-120a antenna, I’ve created this separate page. (This page gets a huge number of hits – apparently even the techs at Yaesu are recommending folks check out the page for ATAS ideas. Thanks, guys – very much appreciated!)
- I use the ATAS with several different mounting schemes depending on where I am and what I’m doing. Below are several photos that show these various schemes. If you mouseover the photos, you will see details about each photo (apparently, the mouseover doesn’t work with Firefox so you might want to start up Chrome or IE if you are really THAT interested in the details.)
- I use Budd’s Vertical Antenna Clamp and special SO-239 mounting kit for portable, picnic and balcony operation. This is a very good approach for very temporary operations. However, with the weight of the ATAS versus the much lighter weight Buddipole, high winds will blow the ATAS horizontal unless guyed.
- As with ALL of the portable operations and mounting approaches, the antenna ONLY works great with a tuned counterpoise. I am finding that a lot of the same issues and ideas that work with the BuddiStick apply to what I am doing with the ATAS-120 for portable operation.
- For radials (I know “counterpoise” would be more accurate, but you know what I’m talking about!), I use three conductor Radio Shack flat rotor cable with each of the three wires cut to a quarter wave for a different band. I usually just use one of these for three bands…but sometimes use two of these to THEORETICALLY give me six different bands. Reality turned out somewhat differently. Surrounding environment and metal….along with radial interactions and radial angles and end heights, change things from all those very precise quarter wave measurements. However, the biggest problem I have found is that just one of the six bands will not auto tune with the ATAS….usually 40 or 12 Meters, depending on the particular portable operation set up. (Side note: I have been surprised how well this thing seems to work on 40…much better than I expected.)
- I use the Diamond CRM mount for our balcony in the mountains. If you are looking for a permanent installation approach for your ATAS, this mount works great with a double barrel SO-239. I recommend one that is about 6″ long.
- I also use another of Budd’s Vertical Antenna Clamp mounting kit with a cheap $18 mini tripod from Wal-mart. I have found this particularly handy for operating portable in the mountains. Note that the mounting kit has to be drilled out to fit the 5/8″ double barrel SO-239. In my case, Bud himself was nice enough to do that for me after I emailed him my intentions about using it with a competitor’s antenna! (As a management consultant to companies all over the world, I’ve seen the insides of a LOT of companies. I have never seen one as good about genuine customer service and quality as Bud’s BuddiPole company. They should be a model for every small company to follow.)
- If you decide to use this same tripod, here are some hints: you will need to pop out the current mounting screw since it is too short for the mounting plate. I replaced it with a longer stainless steel bolt and wing nut. A benefit of this particular tripod is that you can adjust the legs so they are almost perpendicular to the antenna thereby giving a very stable base for the ATAS even when the breeze kicks up….especially stable if the legs are also extended and perpendicular! (In the photos below, the legs are not extended.)
- If you intend to balcony mount or tripod mount the ATAS, I recommend as many counterpoises as possible – with at least one cut as a quarter wave for each band you want to work. Click this Antenna Length Calculator for a quick way to know how long a quarter wave is for each frequency of interest.
- My first mobile contact with the ATAS 120 was a mutual 59 contact with Costa Rica with 20 watts sitting in the parking lot of our Florida condo about 5 minutes after installing the antenna with less than adequate ground strapping. Improving this strapping has greatly improved both reception and transmission. Oops, I should have taken some photos of the strapping too.
- For my mobile installation, I have been using the ATAS 120 with a Comet CP-5M trunk lip mount since a roof mount is more difficult with a convertible! However, I am finding that the CP-5 keeps coming loose with Interstate speeds between Florida and Tennessee – even using Loctite.
- I am relegating the CP-5M to my Diamond CR320a tribander VHF/UHF antenna since it has the same M mount. I have just bought, but have yet to install, the Diamond K400C for use with the ATAS 120. All reviews I’ve read indicate it is a much better mount for such a heavy antenna.
- Update: Having just completed a 2,000 mile round trip to our mountain home and back, I can now report with certainty that the Diamond K400C is a much better mount for the ATAS-120 than the Comet CP-5M. I used Loctite on both – but the design of the K400C is just stronger with no slippage whatsoever – even at 85 MPH speeds for multiple hours (that is theoretical of course since I would never go over the speed limit just because it is a 15 hour trip from Clearwater Beach to Gatlinburg with almost 90% of that spent on Interstates.) I should note that the adjustment range for the Comet IS better than the Diamond for adjusting the antenna so it is vertical from all perspectives.
Bottom-line: I am very pleased with how well the Yaesu ATAS-120 antenna works with all the different and varying uses shown in the photos.
73 / 72,
K3RRR
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73 de Robert K3RRR
http://K3RRR.com
@K3TripleR
http://YouTube.com/K3RRR
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Hey Robert!
I have an ATAS 120A I use on my Ford Transit 350, it is one of my main antenna for POTA. I use it with my FT 891. I have had some very good results with it on most of the bands.
73 de N2NWK
Hi Del,
Great to see here on my website after all the times that we have talked on the satellites!
One bad thing I suffered through when I converted from all Yaesu to all ICOM was giving up my ATAS-120a… Was a great antenna for over a decade and never gave me a problem – seemed to have worked a whole lot better than my Diamond 330.
Hope all is well, my friend!
73,
Robert
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73 de Robert K3RRR
Twitter: @K3TripleR
YouTube.com/K3RRR
Website: K3RRR.com
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Hi Robert,
Thank you for this website. I’ve always been interested in the ATAS120a for my QTH due to restrictions, but have had resivations about getting one based on reviews I’ve read on line. After reading this page, I brought one over the weekend and put it up. WOW. My reception is great. I’ve taken what you’ve written about the counterpoise into consideration as the SWR is a little high. After looking at the wavelength calaulator you’ve referenced, I’ve designed I’m having fabricated a counterpoise system for 70, 2 & 6. My next thing to add coming off my mast will be the counterpoise wires for HF as you’ve described. Thank you so much for going to the trouble to explaining your success with the antenna and more importantly, for us less experienced operators, how you did it.
Regards
Darren – VK3FOAC
Hi Darren,
I’m delighted that the article was that helpful to you… See you on the bands!
73,
Robert
I am using the Atas 120A as a base station with FT857D, all is well with contacts to the other side of the world (From VK3)The problem is that when it rains all I get is a HSWR reading and that means shutting down. I reside in a retireme3nt village where we are not permitted to erect any antennas at all but for all of the the ATAS is almost undetectable to the naked eye. Can any one come up with a suggestion for a wet ATAS 120A.
All the best Mike VK3AUR
My ATAS 120A is good accept when it rains, I’m using it as a base station antenna
with good results round the world from VK3.
can any one suggest how I can use the antenna when it rains. We reside ina retirement village in Melbourne where we are not supposed to erect any antennas The ATAS 120A is almost undetectable to the naked eye at about 12 feet above ground.
All the best mike VK3AUR
michaelwimbornejp3@gmail.com
I am using the Atas 120A as a base station with FT857D, all is well with contacts to the other side of the world (From VK3)The problem is that when it rains all I get is a HSWR reading and that means shutting down. I reside in a retireme3nt village where we are not permitted to erect any antennas at all but for all of the the ATAS is almost undetectable to the naked eye. Can any one come up with a suggestion for a wet ATAS 120A.
All the best Mike VK3AUR
michaelwimbornejp3@gmail.com
Hi Michael,
I’ve never had any weather related issues with mine…
The “a” version of the ATAS 120a includes a rain cap for the top of the antenna where the stinger attaches…you might check that it is in place and working….otherwise, I would look to the coax connection and the coax itself as the problem. You might try with other temporary coax during the next storm and see if that makes a difference. Alternatively, your choice for radials or counterpoises might be the rain impacted culprit.
Best of luck with your quest!
Robert AA5FR
Hello there,
Nice web site & very usefull ideas I learned from you mate, I have made my ATAS & 857 as my home base, but 1 problem I got, can you help me with Ground? As I don’t have sand around me, I need alternative idea please.
Best regards,
A61CD
73
before reading your site i was looking at selling by atas 120a as i could not get the vswr below 4 to 1 but after reading your site i can get the atas to tune all the bands it covers.
Neil VK8NH
Bravo, Neil….so glad that this page was able to give you some guidance for your ATAS…I personally find it to be an amazing antenna when you got the right grounding…
73 de Robert AA5FR
well your site is cool i have not read the 120a article through yet but i had to leave the site for now but i needed to comment on what i see so far i to have the 120a and 857d mobile and in the RV i reside in now for 30 years my towers are scedual 40 steel tubes 2and one half and three inch the three inch is caped and drilled for the antenna the coax is in the tube then it is fed in to conduit to the heater area then on to the radio oh i use it on 2 meter also using a duplexer my counterpoise is a 19 inch stainless bole drilled and up side down on the tower and you bare wright some of the frequencies do not tune in that is because i am still trying to find that sweet spot where they tune. thanks for listening. have a nice day terry AE7MR beekeeper-1
I’m also using an Atas 120A and love it! I already did QSO’s over a distance of 4500km’s / 2800 miles.
I’m only using it for a few months now and cannot wait to see what it can do more!
For pics of my installation: http://www.pd1ca.nl/my-antennas/
Srs,
I would like to know the price of the antenna Yaesu ATAS 120 for radio and if you ship to Brazil what the cost, how do I acquire.
sds
Mauricio
Ola tudo bem?
Gostaria de saber se eu prender na aluminio da porta o batente posso uar sem pproblema? No Yaesu FT817nd .
Thanks for posting this. It’s given me some good ideas while waiting on my reciprocal license …. and made me miss the Smoky Mountains.
73 de KD4RJB
Minato-ku, Tokyo, JP
https://www.facebook.com/photo.php?fbid=222704731076960&set=a.222704711076962.71111.100000123058849&type=3&theater
Hi Robert,
I purchase the ATAS 120A I think in two or three days is in home, I ask you for your experience with ATAS I go to use it in portable, no vehicle, you sugest to my for instaling 1 radial for band (¿?) or copper mesh 2.000 mm x 2.000 mm.
I hope your help.
73´s Ivan EA8YG
Canary Islands
Hi Ivan,
The one thing I’ve learned is that the ATAS has to have a very good ground…when it does, it does an excellent job even on 40 meters. A mediocre ground will get you poor results…not mediocre results. This is true as a mobile or as a portable. I have also found for most of my own portable ham operations, that theoretical quarter wavelength seems to not be that in the real world. For your installation, I would probably start with the mesh and add sloping counterpoises until you got the results you want.
73 de Robert AA5FR