ATAS-120 And Other HF/6M Mobile Antennas

I posted this on a radio forum as a reply to a new ham who is considering the purchase of a Yaesu FT-857 to run mobile, and asked for antenna recommendations. I decided to repost it here. I don't claim to have all the answers, but I have had quite a few HF mobile rigs, and have helped quite a few other hams setup their own mobile HF station. So here goes:

If you use a WB0W antenna, you will be using a Little Tarheel II, unless you don't want to use 6 Meters. This is their smallest screwdriver antenna, and the only one that does 6.
Right off the bat you need to forget 160 Meters. It is not impossible to work 160 mobile (I have done it, but it was on a motorhome), but requires a huge antenna and even then, it is an exercise in frustration.

Also, unless you specifically want to work 75 Meters, it is probably more trouble than you want to deal with. You can have an effective 75M mobile station, but that involves a huge Texas Bugcatcher antenna, ground straps to the frame of the vehicle plus ground radials running along both frame rails for the full length of the vehicle, plus a 500 watt mobile amplifier. And then it is not really a multi-band setup; in fact it is only tuned for a small slice of 75M. Basically, you want this if you spend all your time on one specific net frequency. Forget having a multi-band setup that can be bandswitched while driving and works well on 75M. I'm not saying you cannot work 75 with a smaller antenna, but it will be pretty much emergency only, because the net will stop while they try to find someone who can hear you well enough to relay.

So, you probably want 40M through 6M. Plus 2M/440, of course. The 857 has two antenna connections: a 2M/440 connection and an HF/6M connection. You should use any common 2M/440 dual band antenna you like for that side of things, rather than trying to incorporate that into the HF antenna.

A couple of things you need to understand about screwdriver antennas.
First, most of the ones you see people recommending as being much better than the ATAS are indeed better as an HF antenna, but it is an unfair comparison because A) they are twice the size or more, B) they don't do 6M, and C) they don't autotune. While it is possible to bandswitch one while driving, it is not a good idea, and certainly not in traffic. It is much better to pull over somewhere. It is just about as quick to jump out and swap Hamsticks, although with the screwdriver, at least you can do it while sitting in the cab.
There are a few screwdrivers that have an auto-tune option, but not in the price range you are looking at. I'm not looking at a price list, but you would probably have over $1000 in one of those by the time you are done.

In my opinion, based on my experience as an HF mobile operator and former ham radio store manager, the ATAS is probably a decent antenna, all things considered. If you look at the hams who give it poor reviews, most of them are 2x3 calls and this is their first HF mobile antenna. Because HF mobile, and especially multi-band HF mobile is not really plug-and-play, a lot of these guys would be complaining regardless of which antenna they chose as their first. The vast majority of them are saying the antenna just quit tuning after awhile. In other words, after just about long enough for their insufficient grounding system to deteriorate a bit from exposure to the elements. I think the ATAS is just fine, if it is properly installed.

Here is a low-cost option you may want to consider: a basic Hustler setup with the full-length 54" mast and a tri-band adapter. This allows you to run any three HF bands with no need for bandswitching, plus the mast works as a 6M antenna. So you could switch freely between 6M and let's say 40M, 20M and 10M, without changing anything.
It would be fairly large, but not as large as a Texas Bugcatcher. And it would be half the price of the ATAS. Also, you could carry additional loading coils for the other HF bands, including one that works reasonably well on 75, albeit not as well as a Bugcatcher.
The Hustler can stand up to an amplifier too, if you want to run some power.