Vehicle Mounted Regional Comms - Part 1: ATAS-120A

The military has been using vehicle-mounted NVIS antenna deployments for decades to support offgrid, local and regional comms. In this series, I am going to try several antennas. We'll see which ones work and which ones fail.

Here's my first attempt using the Yaesu ATAS-120A.

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#thetechprepper #nvis #jeep #atas120

[longtonailtrdwtr]

I use a Tarheel antenna little Tarheel. It’s mounted using a similar style trunk/lid mount on the rear driver door, about midway up. This put top 3 inches of the coil slightly above the roofline with a 58” antenna vertical above the roof. I believe this is effectively a 12-13’ vertical and I’ve worked from Kentucky to NC on voice at 10w. I semi reliably get SSB contacts at 10w. This past weekend I used a 100w radio and was easily making SSB contacts. I think a lot of it is overcoming the severely compromised antenna on HF with propagation and wattage.

[vironpayne]

You might stand up the loading coil vertical. Then clip a wire to the tip of the whip. Then connect the other end of the wire to a fiberglass pole on the rear of the Jeep. In essence you would have an Inverted-L antenna that is base loaded on the vertical.

Jason KM4ACK does something similar for his portable HF operations. Others also have done similarly.

The proximity to the roof will be an issue, especially if it is varying while you are underway mobile.

I used 102" CB whip on top of a homemade loading coil fed thru an SGC antenna matching unit at the base of the loading coil. The whole arrangement was on a bicycle carrier that mounted in a trailer hitch reciever.

On the interstate the wind pushed the whip back to where I got good NVIS performance on 40m and 80m.

[IndependentNewsMedia]

If you utilise a longer whip which is long enough to reach the boot [UK] or trunk door [US], you will get NVIS'ish, try to get a much of the whip section over the flat roof. Note there will be nulls due to the body of your vehicle, try to find the nulls they are useful; when you have local'ish interference, you can drive and turn the vehicle with trial and error pointing the null in the direction of the interference and increase the reception quality, works OK'ish on HF, and however VHF/UHF can change from s1 to s5. Keep up the good work, God bless.

[racerveza]

Wow, good timing. I opened YT to look for ATAS-120 reviews, and here you are. I've got the same objective as you - quick deployment of a stationary, vehicle-based station. I can get on the air in about five minutes with my CHA-TDL mounted to a bracket on my receiver hitch. Looking forward to your next experiments. 73 de W9DNE

[TheGeekiestGuy]

I'm always looking at different atas mounts. Thanks for the inspiration, brother. We went to do a POTA today, and the main club radio didn't have its power cable, so we ended up using another members 818. It didn't go very well, but lessons were learned. 😆🤙🏾

[WeaponsJunkie]

Keep working. This is great. Excited to see a solution for the same challenge as well.

[DavidS-iwei]

Nice setup. Try the Yaesu FC-40 and a 102" whip. You will see that, as you change the freq on the radio. The FC-40 will follow the freq as it tunes. The FC-40 is about $275 dollars.

[rufusrizzo]

I have been shocked at how well HAM sticks work. I have done well with 20m and 40m hamsticks. They tune the whole band well. If you want NVIS a bumper mount may work better.

[Subgunman]

Have both th3 Little Tarheel with a longer whip as well as the ATAS 100, the predecessor to the 120. Both are decent antennas. Have used the 100 as a base antenna with the accessory ring that has three different coil loaded whips for its ground plane. Works good in receive so TX will not be a problem.

[Swamp-Fox]

Can't wait to see what you have up your sleeve with your next whip style deployment. The only way you can find out what works is to try it!

[JohnTarbox]

If you look at the tests the US military has performed, they have had very good luck with vertical whips mounted on the back of humvees, where they use rope to pull down the whip's tip behind the vehicle. This would be easier when parked rather than in motion. DE WA1KLI

[jayzee]

Good stuff man. I’ve been thinking about the same lately, how to setup for HF comms between vehicle and home stations. Nvis was on my mind also for that 150-300miles range. Looking fwd to see what you got setup next.

[MrStanwyck]

I always enjoy your videos Gaston. That’s a nice looking jeep setup you have. Have a good evening…

[Crcket]

I too would like to have NVIS setup in the truck. Interested to watch your findings.

[dougdaniels]

Not sure what model that Jeep is, but if it's a JK, there's a great antenna mount for the rear license plate bracket. I got very good tx/rx with it when I had mine.

[JohnJones-opuf]

The ATAS 120a I had was a pos.... I had to send it in for repair after only 2 months. And still it was unreliable. Radio was FT-891

[thuff]

I do enjoy your videos and I have a tarheel on my jeep similar to your antenna. I am not sure what year your jeep is but mine has an aluminum hood that will not support the K400 without bending it. I opted for using a light mount on the a pillar to mount my antennas. I hope your hood is steal and not issues.

[kcowl]

lets try this one more time when you want - my base JS8 station was offline while I was experimenting with the manpack this morning. :-)

[deerslayer]

I thought about this antenna. But here up in western Washington I just feel like it would suffer damage. Lots of one lane roads with vegetation. I hear they are excellent antennas.

[wed_ward]

I'm doing similar tests as soon as I decide on the antenna(s). I was looking to start with some sticks (reg or mini) and mount them parallel and offset from the roof rack rail on one side and play with 40m. My issue is finding someone local to test with. I'm playing off the typical helicopter mounting to see if that will work.