Sparks31 has a brief article up on Covert and Hidden Antennas.
Whether you are setting up a field radio station for communications or a monitoring post for SIGINT operation, the antenna is the linchpin of your setup. The best radio in the world is useless without a decent antenna.
Let’s take a look at a common antenna design, one I’ve used with much success over the years:
This is a discone antenna. I have one at my eastern QTH. For a first antenna it’s not bad. It makes an adequate wideband receive and transmit antenna for the VHF and UHF bands. It’s a unity gain antenna, but its advantage is that you can get on the air with multiple VHF and UHF bands with a single antenna. For permissive urban and suburban environments it’s a good choice.
However, it sticks out like a cow in church. Anyone with a modicum of RF knowledge will know what you’re doing when they see one on your roof. Not a problem in permissive environments like the U.S. today, unless you live in place that has a H.O.A. which restricts antennas, or for whatever reason(s) you want to keep your RF activity under wraps.
Antennas are one of those things that you can easily roll your own out of whatever stuff you have lying around your workshop, homestead, or wherever.
Marconi spins in his grave every time a ham buys an aerial instead of building it.
– Joe W1GFH
KD6TLF also wrote about hidden antennas for purposes of operating where antennas were restricted. His original site is gone, but his article is reprinted here.
Build your own hidden stealth and secret antennas
Learn how to build, hide and operate indoor and outdoor Ham antennas without causing RFI problems. Some of these designs were taken from pirate operations and applied to legal radio.I do not condone pirate radio, but why not apply their hideing techniques with proven ham antenna designs and theory.
Hide your antenna in something else. Extreme Measure for the most severely restricted environment. When NOBODY can know you have a transmitter. For apartment Balcony, Great working! Hanging “HUMMINGBIRD FEEDER” bird feeder 10-40m HF Antenna Instructions. This hides the outside loading coil so your random wire will tune up on 10-40m. Puts substansial portion of your radiated RF outside your apartment-condo…
LOOK AT THESE. DO YOU SEE ANY ANTENNAS? 10-30m and 40m balcony antennas. 10-30m is an AEA Isoloop magnetic loop, (MFJ type loop), and a 40m hamstick bundled with fishing poles to hide. Stick is tuned with wire tuner and artificial ground counter poise. I’m on the 3rd floor.
The loop is covered with a plastic tarp to hide. I get average 559 sig reports every where I go. Even on dx reports. Loop works DX very well. From my QTH in Escondido, Ca I work Asia , Russia, South Pacific, South America, etc points West of me in afternoons on 15 and 20. CW! Also I work all USA and Canada. I have not tried Europe yet in mornings from here yet. I do not operate much in the Extra class band where most of the DX is, because I like ragchew type qso’s. I can’t say enough about these loops. They really perform…
Prepared Ham has a similar article – Hidden Antennas for HOA Restrictions.
There are two antennas in this photo can you find them?
These antennas work great and do not need a tuner. Now I can hear the masses now saying “you could/should have built a resonant dipole….” “Real HAMS don’t buy antennas”…..”Turners are a crutch resonant antennas are the only way to go”…. And I am sure you can come up with others as well…
G4ILO has an article on how to operate at a stealth level at home as well.
If you want to get on the air without highly visible antennas then the best solution will depend very much on your personal situation and what you can get away with. One of the first decisions you need to make is whether to go for stealth or covert operation. I don’t know if there is an official definition of these terms, but for my purposes, stealth operation means “under the radar”. It implies the use of outside antennas that are hard to see, whereas covert operation requires that your activities are completely undetectable. Covert operation may be required in a neighbourhood that has covenants or CCVs specifically banning antennas, but many hams in that situation opt for the stealth approach, and get away with it because nobody notices.
While researching compact antenna options I discovered the following rule of thumb:
- An antenna may have two of the attributes small, efficient or broadband (work over a wide frequency range without retuning) but never all three.
This is something you should always bear in mind when considering your options for low profile or hidden antennas. If it’s small, it is either going to be inefficient or have a narrow bandwidth.
Stealth antennas that work very well are:
- Flagpole vertical. In the USA, I am given to understand, it is the right of every citizen to erect a flagpole on their property, so that they can show they are patriotic Americans by flying the Stars and Stripes. A flagpole can easily be used as, or conceal, a full sized vertical to make an efficient disguised antenna. You can even buy ready made flagpole antennas. In the UK, however, we have no such right, and blatant displays of patriotism tend to be regarded with suspicion, so for most of us it is not an option.
- Invisible wire or dipole. Another good option is a long wire or inverted L made of thin wire which is hard to see from a distance. If the feeder can be disguised then a centre-fed dipole or doublet is also possible. This option does rather depend on the availability of suitably high supports to hang the wire from. Personally I don’t like this idea because I’m also a birdwatcher and fond of wildlife and I don’t want to risk injury to birds who fly in to the invisible wire. Also, in the high density housing developments here in the UK where antenna restrictions are likely to apply, the plots are not big enough to accommmodate an effective long wire, and not far enough apart for such a wire to be really invisible to neighbours. But it is a good option if you can use it.
- Magnetic loops. My top choice for use where disguised or hidden full-sized antennas cannot be erected, a magnetic loop can give full-sized antenna performance for a fraction of the size. Because a magnetic loop does not look like how most people expect an antenna to look, and doesn’t need to be mounted up high, you may be able to install one without anyone realizing what it is. Try mounting it on top of a pole from which you hang bird feeders, or on top of one of those metal obelisks you grow climbing plants up.
- Short vertical dipoles such as the TransWorld Adventurer. I haven’t tried one, but I have heard nothing but great reports on them. They stand about 8.5ft (less than 3m) high, and actually work better (with lower angle radiation) close to the ground than elevated on a mast. Coated matt black, they are pretty hard to see.
- Loaded whip (a.k.a. “screwdriver”) antennas. Loaded whips are mobile antennas. Even the most efficient loaded whip won’t perform as well as a full sized vertical, but by choosing one with a very high Q loading coil such as a High Sierra, you’ll still radiate a reasonable signal, at a cost of needing to retune whenever you QSY any distance. Due to its small size, you may be able to plant your whip in the garden without drawing attention to it. Use a base extension to increase performance, and as many ground radials as possible. Another possibility is to install the antenna on your car or truck and use a trailing cable to connect it to your shack. (If you try this, use a push fit connector such as an RCA phono jack and socket that will part easily if you forget to disconnect the antenna before driving away!)
Radiosurvivalist.com writes about hidden antennas, too.
Stealth is an absolute necessity when you are in survival mode especially when it comes to your communications equipment. The very best communications antenna for a survivalist is one that no one can see. You know yourself that paranoia will run rampant and anything seen as a “threat” will be reported. The last thing you want to do is to draw attention to yourself or your location by having a huge antenna sticking up in the air. Sure, the big antennas work so much better but they also tend to attract unwanted attention. So with this page we will show you some antennas that will perform very well for the bands they are created for and yet will not draw a lot of attention.
Before you go any further on this page you may want to read about a ham operator who specializes in working stealth modes with stealth antennas. The article is entitled: “Secrets of a Successful Stealth Operator“.
What is it? Put simply, it is an end-fed, longwire antenna that is laid right on the grass. Hence the name. The original grasswire used by K3MT in the summer of 1988 was just 204′ of #18 AWG magnet wire laid along the property line, anywhere from 1″ to 6″ above the ground. This sketch shows plan and elevation views of a typical installation. Both an 8′ ground rod and optional counterpoise wires are shown. Use one or the other. Both are not needed. (Click the image for a better view of the Grasswire Antenna.)…
The Villages Amateur Radio Club published a presentation a few years ago covering various stealth antennas. Click here to download a PDF of the slides. It covers flagpole antennas, treetrunk antennas, attic dipoles, birdhouse vees, and more.
Lastly, the Marine Corps Antenna Handbook (PDF – 2MB) has a lot of information about antenna science, improvised antenna parts, and field antennas which can be of aid in building your stealth antenna.