Best way to adapt Yaesu ATAS-120 for portable HF?

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Joe Beeler:
Hi, I am working towards advancing my tech license to extra and have purchased a Yaesu 857D as it seemed to give me the greatest flexibility of working all bands/modes I am licensed for now (up to 440) while also giving me coverage down to 160 when I am ready. I also like being able to use this radio either as a portable, base, or mobile operations.

As part of my purchase I acquired a ATAS-120 antenna on the assumption that it could be used for mobile and portable ops and, with some constraints, base ops. Part of what lead my decision was an understanding that this antenna could be used with a standard camera tripod, but now it seems that was a misunderstanding.

Has anyone a good idea on how to mount this antenna in such a way to get good (or at least reasonable) reception on HF? I have a separate VHF/UHF antenna that I am happy with so I am not looking to use a duplexer to use the 120 on these bands. I've seen one suggestion on these forums of using a metal plate to simulate the ground plane of a car, but that does not seem to be too practical for portable ops. Even hacking a camera tripod to allow me to pass a 239 connector and coax through doesnt seem to offer any benefit since these tripods are plastic (at least those I've seen) and so could not offer any grounding.

Any suggestions would be appreciated. Pictures or diagrams even more so! :-)

Thanks and 73
Joe KG4PVY

Andrew:
"Part of what lead my decision was an understanding that this antenna could be used with a standard camera tripod, but now it seems that was a misunderstanding. "

Joe, what you need are radials to let the antenna work properly.  Not just one, but multiple.  A typical fixed vert. antenna installation will have between 20 to 100 radials.  Now, with that said, I have a homebru vertical which I backpack along with my FT817.  Using 4 radials, I have made quite a few good DX contacts with 5W and the homebrew antenna. Perfect?  No way. Does it get the job done?  Yup.

The ATAS is decent for mobile (I run the 857/ATAS combo mobile), but a good wire antenna will do better for fixed ops (camping for a few days, maybe).  Just depends on what you need to do.  Also, be aware that the 857 REALLY likes power to be at least 11.5V.... below that, audio distorts on my unit.  Tuning of the antenna may also be problematic unless you have enough radials of the right length.  Read up in the ARRL Antenna Handbook about vertical antennas and you'll get some good info & advice.

Andrew
N4ABA

Alan Applegate:
Even over a perfect groundplane, the ATAS 120 is a minimal antenna. While contacts can be made using it, there are better choices for portable operation, like the aforementioned dipole.

The ARRL publishes a booklet entitled "Simple and Fun Antennas for Hams", and at least one of these will fit your needs.

Alan, KØBG
www.k0bg.com

tom lish II:
I run an 857 d in 2 of my cars and one is using a atas 100 and the other is using a atas 120.

they both work fairley well mobile, from 440 mhz to 40 meters. I have a dk-3 on the pickup and it is a bit better , but runs from 6 m to 80 m. and is much larger and has a diffeent set up.

I use a diamond 400k mount on the cars, mount to the side of the trunk so the wind preasure is pushing on the "strong side" of the mount.

for a fixed mount I would reccommend you make a plate as large as possible ( perhaps an old cookie sheet or larger) and put a 2 inch double femal so239 in the center ( buxcomm.com has them for a couple bucks) and screw the antenna on top and the coax under it.  use this plate to mount it to the edge of the roof of the house and then run 6 or 8 radials out at least 20 feet ia all directions (or as many as you can) and 33 feet radials will be better. ground the radials to the plate  the antenna is mounted on.

this antenna need a good ground and a good ground plane.  Ideally you could mount it to the roof of a metal garde shack and do ok.

your easist way would to work would be a atas in the car and a fan dipole at home.  why limit your self at the house where you could put up an antenna say a 2.440/6 on one side and a hf on the other.  a hustler 5btv verticle is $159 and a fan dipole  can be built for about $15

http://www.ku4ay.net/dipole.html
http://www.qsl.net/kd7rem/antdipole.htm
http://www.hamuniverse.com/multidipole.html
http://www.angelfire.com/nb/ni4l/ni4ldipole.html
http://www.arrl.org/tis/info/pdf/9611073.pdf
http://www.geocities.com/n2uhc/2banddipole.html
http://www.qsl.net/na4it/fandipole.html

 

Michael Amper:
Just curious...how are you planning on using the FT-857D as a portable radio? Are you planning on carrying around several large batteries to power it?

Seriously, I have an FT-100 and an ATAS-120 mounted in my car, so I'd like to know.

It shouldn't be too hard to dream up a way to mount the ATAS-120, which has a UHF base, to a standard 1/4"-20 camera tripod mount. I'd wager that you could probably find something suitable at any decent professional photog shop. Your real problem will be, as mentioned above, providing a suitable ground plane for the ATAS. BTW, most professional quality tripods are made of aluminum, not plastic.

Perhaps you should consider the ATAS-25 (which *does* mount on a tripod), a Buddipole, a SuperAntennas YP-series or MP-series, or a Yaesu FC-40 with your choice of wire antenna? I'm currently building my own version of the Buddipole, and I'd like to get a Yaesu FC-20 to go with my FT-100, and eventually with an FT-817ND.

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