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Attic Antennas

Stephen Reynolds (WA4CNG) on July 27, 2000
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Attic Antenna Systems

By Stephen T. Reynolds WA4CNG

Growing up in the early 60's with a new General Class call sign after 1 year as a Novice was great fun. I lived at home with my parents and had lots of trees to string antennas on including an 80 and 40 meter dipole. I later got a tri-band beam up on our roof with rotor. I worked a little DX, but mostly rag-chewed on 75 meters. The DX was on 20 and 15 meters. Well here comes incentive licensing and being the arrogant upstart that I was, I did my own protest at that. So I let my license lapse, waited 30 days, took the General Written test and did 5WPM CW and bought my call sign back for $20 with a technician license. I moved up to the VHF spectrum and had great fun and pride building 2 meter repeaters here in Atlanta in the 70's and 80's. As we all know, the FCC in their wisdom decided to kill incentive licensing. It really never did work, and instituted a much simpler 3 classes of Amateur Radio licenses. I got my general class license back on April 15th along with several thousand others that upgraded.

Well as time goes along so do homes, families, jobs and so forth. In August of 1999 my wife and I moved into our new home in Alpharetta Ga. The home is in a very nice neighborhood with many restrictive covenants. As I was operating on VHF at the time, the large attic and tall roof line provided me ample space to put a dual band Omni 144/440 antenna in it (15 feet high) plus a high gain 800Mhz antenna for my scanner. The ground elevation here is 1200 feet and is one of the tallest ridges in North Fulton County. When your VHF/UHF antenna base is 100-200 feet higher than most all others, Height Does Matter, no matter how you get it, ground elevation or a tower.

Well here comes the FCC with Santa Claus at Christmas time. I have NO trees in the yard (.35 acres), restrictive covenants which meant nothing to me on VHF/UHF, but I am getting back on the HF bands. How do I do this and take full advantage of my general class license, which will arrive on April 15th?

My first step was to buy the current ARRL Handbook, plus their Vol. 6 Antenna Compendium. Both of these provided me with lots of information on adapting antennas for an attic, as there have been no major changes in design in the last few years, with the exception of a couple of antennas on the market right now that seem too good to be true. My attic is 50 feet wide and 40 feet deep with a peak 15 feet high. There are lots of cross members in it along with quite a lot of open space, but it is not long enough for a full sized 40 Meter dipole.

The first antenna I got was an Alpha Delta DX-EE dipole because it would fit in the space available. In my work I have access to some very good Antenna Bridges. I fine-tuned this antenna for the center of the Phone Band on 40-10 meters. The DX-EE works great on 40-10 with reports from all over saying 'you gotta hear your signal from that attic mounted antenna with 100 watts SSB'. It is installed as a slightly inverted V.

I next purchased a Square Loop antenna, strung it around the furthest corners of the attic. I had to cut some of the wire off to get it to fit and stay square. This produced a resonate frequency of 8Mhz instead of the desired 7.2Mhz. It was off to HRO for an MFJ 949E tuner. This antenna serves well on 40 and 20 for DX. I bought a 1:1 balun and built a copy of the 40 meter loop for 20 and 10. It is resonant on 20 and 10 and with the tuner on 15. Square loops are quieter and have a higher take off angle which is needed sometimes for DX depending on the distance to some countries.

The FT-100 I purchased is good for 160M-70CM all modes. The next thing on the agenda was horizontal polarization on 144/440Mhz (Satellites). The candidate was the Eggbeater antenna with ground plane assembly. Up it went on a 12 foot mast. Now I am all set to go out and scare up some DX.

I have now worked 70 countries using the attic mounted antennas. I can easily hold my own in the pile-ups, by waiting my turn in line, instead of blasting away with 1500 watts and stacked 5 element monobanders at 150 feet fed by 7/8in hardline. My feed lines are all 50 ohm double shielded teflon insulation with silver plated center conductor. None of them is over 35 feet in length. My current ham shack is part of the computer room on the second floor below the attic. All of the feed lines go through 1 gang box hole in the wall like a telephone outlet with 5 outlets. I have two antenna switches for multiple uses through the tuner.

I have just pulled two runs of inch super flex cable from the attic down to the Terrace Level of the house into the room where I am building my shop/shack. I fear that when I get that room built, I will be moved into it for my ham shack. Not a problem, there are several very good remote coax switching systems out there. One of the best joy's of Attic Antennas is that I do not have to go grounding them or worry when a storm comes up. I sometimes keep operating anyway. My neighborhood has all underground utilities. The rig is run off of a 1000 watt computer UPS system, plus I have a Whole House surge protector on the main panel.

I am currently scheming a way to get a Stealth multi-band vertical mounted in a backyard flowerbed and when it becomes a reality I will write about that adventure also. The last thing I will do before I get moved into the Terrace Level shop is to run one last wire cable from the basement into the attic and one turn around the attic. This will be an indoor long wire out of 10ga stranded wire. I currently use my tuner with the DX-EE on 75 meters, but the efficiency is real low. It may take a full gallon with the DX-EE and tuner to be able to talk where I want to on 75 meters, or the indoor long wire may get the job done.

I have just bought a second DX-EE antenna and installed it 90 degrees around from the first, with the two feed points on top of each other. This makes for an interesting way to switch TX/RX lobes from N/S to E/W depending on where the signal is coming from. I also have just completed my required FCC RF Exposure survey and passed as all antennas are 6-15 feet up in the attic, and the second floor is 10 feet high in the house, you cannot get physically close enough to get into a controlled or uncontrolled area near the antennas. With this done I need not post any of the yellow notice signs in my house.

Member Comments:
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Inside Antena and Lightning  
by AC5WA on July 27, 2000 Mail this to a friend!
Don't believe you are "safe" because your antena is inside your house. HUGE voltages can be induced by nearby strikes, even cloud to cloud strokes. I have sat in a building under construction and watched and heard arcs jump from the end of an unterminated cable bundle to the side of the junction box which was grounded. The foreman was "encouraging" me to continue working until I showed him the sparks. I got a break until the storm moved. Loops may not be as bad as dipoles or vertical antenas but the "potentinal" is still there.
 
RE: Inside Antena and Lightning  
by WA4CNG on July 27, 2000 Mail this to a friend!
One unique thing about the DX-Series of antennas is that the center insulator has a built in surge protector that greatly reduces the chances of induced voltages from the open end design of a dipole. The closed square loops fed by a balun have this as part of the design of the closed loop. Under these circumstances I do feel safe enough. When I move to the Terrace Level, I will have standard surge protection from the antennas where they enter my shack grounded via a 2 inch flat copper bus to my newly installed gound system on the outside wall. Thanks for the comment.
 
Documentation Source  
by K3AN on July 28, 2000 Mail this to a friend!
EVERY HAM who has any kind of antenna inside or outside his or her house should go to the Polyphaser web site. The site has numerous documents in PDF format that can be downloaded. Document PTD1016 is titled "Ham Radio Station Protection." It is 11 pages long. I suspect there will be other titles on their list that you will want to download.

www.polyphaser.com/technical.htm is the page to visit. It lists all the available PDF documents, with a brief description of each.

Polyphaser also has, or had, a document titled, "The Grounds for Lightning Protection." I couldn't find any reference to it on their site, but I didn't do an exhaustive search.

 
N9PO  
by N9PO on July 28, 2000 Mail this to a friend!
Thanks for sharing your set up with us. I too found the need for an indoor antenna after moving from a rather unrestricted area of Virginia to Chicago, Il. Moving from house to apartment. I am on the third floor and have acess to the attic in my building so I installed a G5RV JR in February which has been giving me great signal reports. I also added a 2 m vertical to get me back on VHF and from a height of 40 ft inside the attic have no problems getting into repeaters in Milwaukee with a 1/4 verticl and 20 W. So N9PO is back on the air from 40m-2m with attic antennas less than 2 miles from O'Hare airport.
 
G5RV Jr. and Others In Attic  
by AB0HI on August 1, 2000 Mail this to a friend!
I too have a G5RV Jr. in my attic. I have it placed in the attic above the garage in a square configuration. The ladder line then runs down into my garage and the coax then runs down into my basement. It tunes perfectly on 20 meters does well all the way down to 40 meters and quit well up to 10 meters. I also have my discone scanner antenna up there along with 2 meter and 6 meter base antennas. I am satisfied with the results and there is no weather related(rain, ice, hail, heat, cold ) wear and tear on them. They have been up there 5 years and have never needed any maintenance.
 
Additional Info  
by WA4CNG on August 2, 2000 Mail this to a friend!
Several E-Mails have come to me directly most with the same request for additional information.
1. How much clearance around the various antenna wires do you have. I have a minimum of 3 feet to any wood support, more than 6 feet to metal (HVAC Ducts). Arcing to anything at even high power is not an issue. I use standard antenna insulators for end terminations, and only 100 pound test nylon cable as there is no wind load!
2. TVI/RFI I had two issues while using my tuner to load the 40 meter square loop and the DXEE on 160. My treadmill started to run and the GFCI on the Jaccuzi tripped. So much for 160. I have a 60 mile Radio Shack VHF/UHF antenna in the front attic space directly under the square loop and one end of one of the DX-EE's, plus I also have a Hi-Pass filter on the input to the distribution amplifier that feeds the whole house, it is very clean on most channels when running 500 watts, NO TVI with 100 watts.
3. I have added a 500 watt amplifier to the station (ALS500) and have had no problem with it, plus my Radiation Exposure calculations are made with a full 1000 watts just to make sure I have plenty of room for Non Exposure.

I will be happy to continue to answer quesitons here or via direct E-Mail.
 
Attic Antennas  
by KC2GUC on February 27, 2001 Mail this to a friend!
I started with an atic DX-EE and then discovered the W9INN dipole. In 42 feet I have a 10-75 meter antenna that works well with a tuner (have reached CA and Norway on 75 meters).

The same tuner would not tune the DX-EE on 75.

W9INN hand-built antennas (built to your desired frequency) are in a very small ad in the back of CQ/QST. Very satisfied. I have no financial incentive to write this; Just think Bill does a good job.

How well does the Egg beater do? I am thinking about it for satelite and was not sure if its too much of a compromise.

kc2guc, jeffrey, scarsdale, ny
 
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