ATAS 120 in the attic

I posted a private question to Moleculo and he suggested I get it into forum. I've read the posts already about throwing the ATAS 120 out the window and have filed them away as possible "I told you so's from others". Before I do the copy and paste, here's the update. The ATAS 120 has been installed and the rolled flashing isn't quite done since I ran out. The antenna is tuning fine on all but 40m. The other glitch in my plan of using two AB Switches one to switch from the LDG-100 Tuner and ATAS-120 and the other AB Switch switching from a Solarcon A99 outside and 10-80 trapped dipole in the attic too. Bouncing back and forth to the tuner and the ATAS-120 is a smooth transition since setting keep having to be changed. The configuration I'm shooting for is to match my pickup install, FT857 with AB Switch to the ATAS-120 and to a 75m Hamstick thats tuned. I'm open for any advice and suggestion (besides tossing the Yaesu screwdriver I've heard that one)

Here's the post:

I know the ATAS 120 has taking several bashings, but I've been using one on my pickup for about 4 years and its worked great. Only time I take it off is when I go through a car wash or take the truck in for service. There are five of us hams that have a yearly competition on DX for distance. Only three of us are really throwing blows (friendly) at each other. Two of those have tall trees and yards and it drives them crazy I keep beating them out sitting in my pickup with the 857 and 120. Every few months they are doing something different, different antenna, higher up into the nosebleed tops of the trees, and they still can't top my Antartica contact on 15m. I've been toying around the house with something that can rival my pickup because sitting in it on cold winter nights by the side of the house isn't so fun. Here at the house I added that trapped dipole thats zigzagged all over my attic (I have an 857 in the house too), and it does ok on 40 and 80 not as well as my truck though. I also have a 75m Ham Stick on the truck with a switch. A few months back I put up a Solarcon A99, at the advice of my competition since they both have one up and its been ok but I'm pushing the envelope in the neighbor hood and have heard comments. Again my pickup smokes it hands down, if there is a DX station or a state I need and I'm not making the trip I run to the truck and usually make the QSO. Sorry about the long drawn out story here, but here's the wrap up. I bought another ATAS 120 for my attic and this is my plan. The open attic that I have to work with is only about 20 x 25. I planned to mount a quad electical j-box to ceiling joist (bottom chord of the truss) just about over my radio in my shack (3rd bedroom office) on the 2nd floor. The base connector will poke up through the j-box and I'll fan out 12" wide rolled galvanized roof flashing is all directions (about 6) to get lengths out as far as possible. The ATAS can extend it full length without contact to the peak and I have nothing but a half dozen small attic vents placed along one side of the peak. One piece of rolled metal may be able to stretch out to a rather inaccessible area over our master bedroom to a length of almost 40'. I haven't quite figured the grounding yet, my YT-100 is grounded to the house copper strung through attic. I'm powering my radio through a Powergate PG40 connected to a Yaesu PS and a 54Ah sealed battery. I pounded in 1/2" 6' copper rod but haven't punched a hole through the wall to drop wire to it yet. No pretty way to get there but on the exterior surface. The holes patchable I guess, if I sell the place.

Thanks for support and questions. I'm using the Diamond UHF Base Conector and 13' RG316 coax which goes up through the ceiling almost over the top of me. The connector is fed out of top knockout in a 4" quad electrical j-box. Each of the sheets of flashing have 3/4" holes at the end and are stacked on the connector and tightened down. The pattern is fanned out in only five directions for the moment (ran out of metal), the longest is fifteen feet and the shortest is eight. I have a long run I can still make and a short 6' going due north, the long one will be about 30' and go northwest.

The plan is to use the 857 to tune the antenna and I'm bagging the LDG for now and will keep it in the truck for field work. I'm going to pull the dipole out competely for now since it runs inches away from the top of the ATAS. The Solarcon A99 will come down but I did connect the Hamstick on the outside of the house right near the vertical and swapped the coax to it and checked in to a net on 80m with no problems. The SWR reading was 1.3 to 1 here in the house on the Hamstick.

I'll shoot some pics this weekend or Monday if the I get drug away from the house.

I'm very greatful for the advice.

Thanks

Bryant
W7BDB

Here's a another side conversation that took place before I posted on this forum.

The key to getting this to work as well as possible is going to be your groundplane, which from what you described, sounds like you've thought out pretty well. One thing to be careful about: You mentioned trying to run wire down the wall from the antenna to the ground rod. The problem with doing that is you might turn that run of ground wire into something that resonates like an antenna, causing RFI problems in the house. You really don't need to ground the antenna because it's not going to be susceptible to lightning in your attic. The flashing that you're laying down below the antenna will act as the groundplane that the antenna needs to see. I suspect that this whole setup will work better than your truck, as it sounds like you're increasing the overall groundplane.


Well its installed, thanks for the grounding advice. If I had tackled that I would probably still be working on the project. Went in fairly well, lots of crawling around in a hot attic (not too bad here in OR). My plan has a few glitches I didn't think through enough. First off it won't tune 40m and I ran out of sheet metal so I will install a couple more runs next Monday and see if that helps. The longest run didn't get put in, so 15' is the longest and the shortest is 8' and there are only 5 runs from the antenna. I do have that zigzagged 10-80 trapped dipole in the attic and had planned to use it for 80m anyway but I slapped up the 75m Hamstick in place of the A99 vertical and it worked great checking into the OEN on 3980. My uh oh was the two switches where I had planned to use one for going between the ATAS and the LDG YT-100. That wasn't as easy as jumping back and forth like in my PU with ATAS and Hamstick, the tuner interfaces the radio as does the ATAS. So I'd lose the init to ATAS when I tried the dipole using the LDG. So for that to work I'd have to keep changing the setup. Hopefully I can get 40m on the ATAS, keep the Hamstick and pull everything else out. I don't use 160, mainly because I can't tune to it anyway. I can always carry the LDG in my pickup and build a 10-160 I can raise in the trees when I'm in the field.

Click to expand...

Climbed up and pulled the dipole out, didn't run any more sheetmetal yet but did swap out the coax w/UHF connector and put in a SO239 bulkhead and ran RG8U giving me a little more slack. It also allowed me to tighten down better in the j-box and put a T in for the shunt coil if its needed. It tunes 6-40 great, got a good signal report on 6m but the other bands aren't too swift at the moment. Confirmed signals in the mobile are about as weak as in the house.

Adding a couple pics, I'll get some more when the metal is complete plus get full shots after I clean my mess up.

Do you think the shunt coil is must anyway?

Thanks for the advice. Didn't mean to say the truck is better than the house, thats an unknown at the moment. They both have the same antenna and radio. I do have the radio running on a battery, with backup from a power supply. The Powergate 40 is connected up to the radio. Would love to have "real antennas" all over the place if I had the room and property. The tuner has moved to the box it came in for now, the ATAS is tuned to the freq. No stray RF or my wife would be the first one to kick down the door to my shack.

"Big Chief talk- little woman listen" ....I've always subscribed to the theory that there are only two types of men, those that are whipped and those that are liars. I'm just sayin... From antenna to the fact of life, one can learn everything in this forum.

Propagation is getting pretty deep around here, I'm going to put on my tinfoil shoes! Post some pics.

Update, added the rest of the flashing metal today. Made good contacts 10, 15, 17, 20, and 40 even with the lousy band conditions. Of course it helps having everyone working hard on field day eager to make contacts.