Magnetic Loop Antenna (above) - This hardly looks like an HF antenna to the untrained eye.
Stealth antennas — Concealment of a radio antenna (or antennas) is needed when you wish to avoid advertising to the public that you are transmitting. Some of you are reading this and now realize the radio system that you are considering is going to need an effective antenna. Consider the stealth antenna.
Why would you need to worry about stealth? Some of you may be facing situations where drawing attention is not desirable due to theft, or restrictive home owner’s associations rules. Perhaps a belligerent government is cracking down on radio operators. Maybe you are planning ahead to avoid having neighbors drop by when they are experiencing RFI issues. It is a bit surprising, but a big highly visible antenna connected to a radio that has been turned off for weeks has the potential to be blamed for bad television reception, cell phone issues, you name it. Some people wrongly blame the owner of a large radio antenna for RFI issues. It is the knowledgeable radio operator who is a good source of information to help the neighbor tack down their RFI issues (usually a bad dimmer switch, etc.). Stealth antennas can help you avoid this situation because the presence of a radio transmitter is not known to others.
In the video Last Voice From Kuwait, a radio operator was able to maintain communications with the press during the Iraqi invasion of Kuwait in 1990. You can bet his antennas were very well concealed. His life depended on stealth. Stealth in operation allowed the rest of the world know how awful the situation really was.
Two subsections of antennas:
Above 30 MHz (VHF, UHF, Microwave) and below 30 MHz (HF, MF, LF).
Above 30 MHz:
The higher the frequency, the smaller the antenna. Smaller antennas are much easier to conceal. For example, a UHF antenna for the 70 cm amateur band, FRS and GMRS can be concealed while maintaining transmission and reception effectiveness. A UHF antenna can be hidden inside of a vent pipe outdoors on top of a roof. That is much better than having to hide the antenna in an attic space. The signal will not be attenuated if it is outdoors. A VHF antenna is a little bit larger, but it is also easy to hide. The 2 meter band and 70 cm band (amateur radio service) can use the same antenna. This solves having to hide multiple antennas. Microwave antennas are easier to conceal because they can be made to look much like satellite TV dishes that are everywhere. No one seems to question a TV dish antenna.
I once hid a small 2 meter/70 cm band antenna inside of a Plastic Owl. The owl served two purposes, it hid my antenna and it scared birds away from my yard. Consider dressing your antenna up with non metallic items. These can hide the true nature of the antenna.
If your situation makes an outside antenna totally unavoidable, try placing the antenna in an attic. Make sure the antenna is not under a metal roof otherwise the signal will not make it out of your home. Keep this antenna as far as you can from electrical wires. Consider a exposure test and use low power with any antenna mounted indoors.
Below 30 MHz:
As the frequency is lowered, the length of the antenna gets longer. An Antenna for the 10 meter band is much smaller than the antenna for the 160 meter band. With HF bands, you need to be a bit more creative to conceal an antenna. Some antennas are easier to hide than others.
For example, wire dipole antennas are very easy to hide however, vertical antennas are harder to conceal. Example, a Multi-Element Yagi antenna on a tower is begging to be noticed and an inverted v wire dipole on a tall mast that uses wire with black insulation is very difficult to see from a distance. Also, put something on top of the mast like a wooden weather vane and the antenna wire could be viewed as support wires by the general uninformed public.
Other Stealth Antenna Ideas:
Many people place wire antennas under the eves of the roof. This method works well and it is well hidden from others. A fresh coat of paint (non metallic) on the wire and the wood structures will make the antenna almost invisible. The proximity to the building and the couture of the building may affect the signal, but at least it allows you to be on the air.
Another great option is to put up your antenna for a short period of time after dark. A wire dipole with black insulation at night time is almost impossible to see in the dark. A yagi antenna on a portable mast is also hard to see at night. Turn off any outdoor lights that might attract attention to the antenna. Don’t forget to remove the antenna when you are finished using it. An antenna can also be set up on a balcony. Some users have spooled wire out of a window on a high rise building. Use your imagination.
Both large and small antennas can be hidden in trees. That hard to see wire antenna is difficult to see in a tree. Best of all, the tree makes an excellent support mast. This type of arrangement should be temporary. That well hidden antenna can easily be destroyed should the tree collapse in a wind storm.
Sometimes the larger antennas are easier to hide than the smaller ones. Large antennas can be run along the top of a fence. The signal may not be the best due to the low height of the antenna, however this will be better than nothing. A 160 meter band antenna can be partially run on a fence and up the face of a house. Larger antenna can be shortened with coils. Coils make the antenna appear electrically longer so that a short wire antenna is resonant at the desired frequency. Keep in mind that coils may reduce the usable bandwidth of an antenna. A reduction in bandwidth makes it harder to transmit (due to higher SWR) on a portion of the band.
Wire antennas are far easier to conceal than a vertical whip antenna. Wire antennas are far more portable since they can be rolled up ans stowed in a bag. A wire antenna for the 40 meter band is easier to store than a CB radio antenna, however a CB radio antenna and a 10 meter band antenna would not look out of place on a car. Some radio operators have run a cable from their home base station to a mobile antenna mounted on a car. To the casual observer, the car with a mobile antenna does not look out of place. Just remember to disconnect the cable before driving away the next day.
Hide In Plain Sight:
Consider using an unusual looking antenna and most onlookers won’t realize what it is. Take the magnetic loop antenna (photo at the beginning of this post). This type of antenna is a small compact loop of conductor. It can be vertically or horizontally mounted. The small size and unusual look allows this type of antenna to be hidden in plain sight. These antennas (stealthy and unusual), are very potent. They can send out s signal comparable to a full wavelength antenna. A fake bird’s nest resting on a horizontally mounted magnetic loop antenna probably would go unquestioned for years.
Go mobile and take your radio and antenna with you. A quick setup at a park with a portal power supply will get you on the air for your communications needs. Once you re done, break it down and leave. There are so many options for mobile operation. One person I know has operated cw from a coffee shop with a small length of antenna wire.
Use caution with antennas that can come in contact with people or animals. One should take RF exposure into account when any antenna is mounted. If the antenna is indoors this is especially important. Use low power and shorter duty cycles when you can. This will help you avoid excess RF exposure.
In summary, plan ahead and look for areas that might allow you to effectively conceal your antenna. When disaster strikes, be charitable to others. This is the time to bring trusted neighbors over to allow them to use your communications systems to to let their families know they are all right. They will rarely question that wire hanging up in your back yard when the disaster is over.
Thank you for viewing this post. Please comment below with your suggestions, feedback and ideas on ways to conceal an antenna. Great ideas are always welcome and benefit others.
Here is an excellent video from You Tube user MeOnTech. He concealed a 2 meter band j-pole antenna on his balcony in a flower pot. Way to go!