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Clandestine Antennas for Amateur Radio. By Craig Bradley, AE6RR. “BY PROHIAS”. -••• -•--    •--• •-• --- •••• •• •- •••. Background. First licensed as WV6SVW & WA6SVW 1961 to 1967 No antenna restrictions (except parents) Life was good Relicensed in 2004 as AE6RR

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Clandestine antennas for amateur radio

Clandestine Antennasfor Amateur Radio


Craig Bradley, AE6RR


-••• -•--    •--• •-• --- •••• •• •- •••

AE6RR – Clandestine Antennas


  • First licensed as WV6SVW & WA6SVW

    • 1961 to 1967

    • No antenna restrictions (except parents)

    • Life was good

  • Relicensed in 2004 as AE6RR

    • Main residence had minimal lot lines and CC&Rs

    • Vacation home in Truckee had CC&Rs but a large lot with some tall pine trees

    • Antenna prospects did not look good

    • XYL thought that I had lost my marbles

      • I was climbing up in the attic, on the roof, staring at trees

AE6RR – Clandestine Antennas

This presentation
This Presentation

  • Clandestine vs. Stealth antennas

  • What makes an antenna work

  • Multiband antennas

  • Possible locations

  • How well do they work?

  • RFI

  • QRO

  • Reference Material

AE6RR – Clandestine Antennas

Clandestine vs stealth antennas

Clandestine vs. Stealth Antennas

What is the difference?

AE6RR – Clandestine Antennas

Stealth antennas
Stealth Antennas

  • There have been many talks, books and articles on Stealth Antennas

  • They are “Hard to See”

  • Construction varies

    • Thin wire antennas in plain view

    • Towers and beams painted in camouflage colors

  • Scheme is to blend with the background and minimize visual impact

  • The antenna concepts in this talk can also be used to construct Stealth Antennas and others

AE6RR – Clandestine Antennas

Clandestine antennas
Clandestine Antennas

  • Clandestine means “Hidden”

    • Should not be visible to someone that may be looking for it

    • May be hidden in plain sight (looks like something else)

      • Flag pole, rain gutter, fence, etc.

    • May be hidden in or on a structure

      • On top of roof

      • Attic, indoors, shed, etc.

    • If you have CC&Rs

      • Clandestine antennas will not need to be explained

      • Stealth antennas may be discovered

    • Once discovered, you will be a suspect

      • Increased surveillance may result

AE6RR – Clandestine Antennas

What makes antennas work

What Makes Antennas Work?

Get the RF in the Air

AE6RR – Clandestine Antennas

Some antenna basics
Some Antenna Basics

  • Most of the RF is radiated from the high current portions of the antenna

  • The highest current is where the impedance is the lowest

    • At the feed point

  • The lowest current is where the impedance is the highest

    • At the end points

    • The ends have the highest voltage

  • The end points don’t radiate much RF

    • They do contribute to the tuning of the antenna

    • They act as “capacity hats”

AE6RR – Clandestine Antennas

Bent antennas
Bent Antennas

  • If you don’t have space for an antenna why not bend the ends around?

    • You can get a lower frequency antenna in a much shorter space

    • The ends don’t radiate much RF so it doesn’t matter where there are pointed

    • The ends do have high voltage present so be sure to insulate them well

AE6RR – Clandestine Antennas

Bent antenna example
Bent Antenna Example

  • Conventional wisdom says that you can’t bend an antenna back on it's self

  • SteppIR does not agree…

AE6RR – Clandestine Antennas

Antenna tuners
Antenna Tuners

  • Antenna Tuner is a misnomer

    • It does not “tune” the antenna

    • It is an impedance matching device

  • Modern transceivers and amplifiers are designed to match a 50 ohm load

    • If the antenna is not 50 ohms you will have a miss-match (high SWR)

    • Most solid state transceivers will start to limit the output power if the SWR is higher than 2:1

  • A tuner will make your antenna “look like” 50 ohms to your radio

    • You will get full power out

AE6RR – Clandestine Antennas

A word on swr
A Word on SWR

  • The Voltage Standing Wave Ratio (or just SWR) is the ratio of the maximum and minimum voltages on the transmission line

  • It is caused by the interaction of the forward and reflected voltages on the line

  • If your antenna and transmission line impedance matches your transceiver output impedance there will be no reflections

  • If the impedances do not match there will be reflections on the line

  • SWR is not a measure of how well an antenna radiates

    • Dummy loads have an SWR of 1:1 …

AE6RR – Clandestine Antennas

Reflected power
Reflected Power

  • Gooch’s Paradox “RF Gotta Go Somewhere”

    • Stealth Amateur Radio by Kleinschmidt

  • It will “bounce” back and forth on the transmission line until it goes somewhere

  • It can be radiated as RF by the antenna (good)

  • It can be radiated as heat by the transmission line (bad)

  • It can be radiated from your station “ground” (bad)

  • It can be radiated from your microphone (burned lips)

  • It can go into your home electronics (bad)

  • It can go back into your transceiver and cause it to limit output power or cause heating or damage (bad)

AE6RR – Clandestine Antennas

A word on transmission lines
A Word on Transmission Lines

  • Transmission lines have losses

    • Usually rated as dB per 100 ft with an SWR of 1:1

    • The losses are much higher at high SWRs

  • Reducing Loss

    • Place the antenna tuner as close to the antenna as possible (lowest loss)

    • Use balanced line between the tuner and the antenna

    • Use low loss coax to feed the antenna (LMR-400 or 9913)

  • If you don’t lose power in the coax you have a better chance if it “getting out”

AE6RR – Clandestine Antennas

Transmission line loss
Transmission Line Loss

The following table is for 100 ft of transmission line with an antenna impedance of 1000 Ohms non-reactive at 14 MHz (Source TLW program by N6BV)

AE6RR – Clandestine Antennas

Unbalanced antennas
Unbalanced Antennas

  • Verticals or Long Wires

  • Require radials (more stuff to hide) or a good ground (hard to do)

  • May result in “RF in the shack” with bad grounds

  • May “stick up in the air” – harder to hide

  • You can “tune” the ground system but now you have created a balanced antenna…

AE6RR – Clandestine Antennas

Balanced antennas
Balanced Antennas

  • Dipoles, Doublets, G5RVs, Loops etc.

  • No ground or radials required

  • Less chance of “RF in the shack”

  • Simple low cost construction - usually wire

  • Can be bent around to fit the space

  • Keep most of the radiation at the antenna

AE6RR – Clandestine Antennas

Loaded antennas
Loaded Antennas

  • Loading coils can physically shorten an antenna

  • Highest current is between the feed point and the coil and the lowest current is after the coil

  • Maximum radiation will be from the portion between the feed point and the coil

    • Maximize the length of this part

  • Loaded antennas are more complicated to tune

    • Nearby objects will interact

  • If you want to get on 80M, you may need to consider a loaded antenna if space is limited

    • RFI noise may be a big problem here

AE6RR – Clandestine Antennas

Loop antennas
Loop Antennas

  • Loop antennas can fit in many places

  • Outdoors may be hard to support it and keep it concealed

  • Indoor horizontal loops can run around the top of your room or around the attic

  • Small loops can be vertical and indoors

  • There are several companies that sell loops and many construction articles

  • You may need a special loop tuner

  • Many Hams have had good results with them

AE6RR – Clandestine Antennas

Multiband antennas

Multiband Antennas

Want to get on more than one band?

AE6RR – Clandestine Antennas

Required equipment
Required Equipment

  • If you want to operate on multiple bands with a simple antenna you will need an external Antenna Tuner

    • Most internal tuners will only match an SWR of 3:1 or less

    • You will need a good external tuner

    • Auto Tuner preferred

  • You can easily get a simple antenna such as a dipole to resonate on a single frequency

    • With a tuner, it will load on many bands (higher frequency)

  • Multiband antennas

    • Can be complex

    • Are very difficult to get working close to other metal objects

    • Clandestine antennas will likely be near many unknown objects

    • Will probably have a high SWR on some bands

AE6RR – Clandestine Antennas

Types of multiband antennas
Types of Multiband Antennas

  • Trapped Verticals

    • We already talked about verticals

  • Horizontal Balanced Wire Antennas

    • Fan or parallel dipoles

    • Trapped dipoles

    • Doublets

    • G5RVs

AE6RR – Clandestine Antennas

Possible locations

Possible Locations

Time to use your imagination

AE6RR – Clandestine Antennas


  • Can be done but should be your last choice

    • Limited space will require very compact antennas

    • Loops and bent wire antennas for the higher bands may be possible

    • Small current loop antennas may be usable

  • RFI will be a problem (Transmit & Receive)

  • RF exposure to you and your family will be higher

    • QRP may be required

  • The XYL may not consider your creation “decorative”

    • You won’t see indoor antennas on HGTV or in home decorating magazines

AE6RR – Clandestine Antennas


  • If you have an attic that you can get into this may be a good possibility

  • Large attics can offer many opportunities

  • You may be able put a small beam in a large attic

  • You don’t have to worry about the effects of weather

  • Attics may contain HVAC ducts and wiring that can affect the performance of your antenna

  • RFI is a consideration

  • Be careful not to step through the sheet rock!

AE6RR – Clandestine Antennas

In the yard
In The Yard

  • Verticals can be hidden in trees

    • You will have to deal with the radial/ground problems

    • Vertical dipoles may be possible in higher trees

    • Flag pole and bird feeder antennas may be possible

  • Thin wire between trees or from a tree to the house may work

    • Thin wire is easy to break and you may have to replace it often

  • You may be able to string wire along the top of a fence

    • An antenna this low will probably be good for NVIS not DX though

AE6RR – Clandestine Antennas

On the house
On the House

  • Rain gutters have been used by some

    • You will have to bond all of the sections together

    • Corroded connections can generate harmonics and RFI problems

    • This system will probably be unbalanced

  • You could run a wire around the house under the eves

    • May not be very effective on a stucco house

AE6RR – Clandestine Antennas

Tv antennas
TV Antennas

  • A TV antenna could be used as a vertical

    • The TV lead-in (300 ohm line) could be part of the antenna

    • The actual TV antenna is a capacity hat

  • FCC regulations state that HOAs must allow TV antennas

  • You could use a log periodic for VHF/UHF

    • 6M, 2M, 220, 440 and 1.2 GHz

    • It looks like a TV antenna and will receive TV signals

AE6RR – Clandestine Antennas

On the roof
On The Roof

  • A wire antenna is very hard to see from the ground if it is low to the roof

    • This is the highest location on the house

    • This location has the least RF obstructions

  • Two story houses are even better

    • The antenna is higher and harder to see from the ground

  • You can build a very good dipole or multiband doublet on the roof

    • By bending the ends you should be able to cover 40 through 6 M

    • Use chimneys, vent pipes and other existing items on your roof for supports

AE6RR – Clandestine Antennas

How well do they work

How Well Do They Work?

Results & Limitations

AE6RR – Clandestine Antennas

What worked and not
What Worked and Not

  • 20 M Ham Stick Dipole in the attic

    • My first try

    • I couldn’t hear much (weak signals and lots of RFI)

  • 20 M Wire Dipole on the roof

    • Worked great (good SWR and DX)

    • Single band though

  • Parallel Dipoles on the roof

    • Only would load up on lowest band

    • Tried a couple with no good results

    • More wire on the roof for people to see

AE6RR – Clandestine Antennas

Back to basics
Back to Basics

  • Next I went back to the 20 M Dipole and added an auto tuner

    • Worked on 20 – 10M

    • More than one band finally

    • But what about 40M?

  • Tried a 40M Dipole with bent ends and the tuner

    • Worked good on 40 and 15M

    • Not so good on 20M but it would load

AE6RR – Clandestine Antennas

My bent antenna
My Bent Antenna

  • Finally tried a G5RV Jr.

    • Half size G5RV (51 ft.)

    • 16 ft. 450 ohm ladder line

    • Balun to 50 ft of 9913 coax

    • Auto tuner

  • The last 6 to 8 ft of each end is bent at about a right angle to the main portion of the antenna

  • This antenna works on 40 through 6 meters and fits in less than 40 linear feet

    • 15M is the worst band but it does work

  • I have been using this antenna for over 3 years

AE6RR – Clandestine Antennas

Antenna view from front of house
Antenna View from Front of House

End of G5RV Jr.

VHF/UHF/1.2 GHz Whip

Bend Point

AE6RR – Clandestine Antennas

Back end of g5rv jr
Back End of G5RV Jr.

Antenna Wire

Tie Cord

AE6RR – Clandestine Antennas

G5rv jr antenna scan
G5RV Jr. Antenna Scan

AE6RR – Clandestine Antennas

Dx results
DX Results

  • Worked – 2004 to Present (a few were with other wire or mobile antennas)

    • 162 Entities

    • 370 Band/Entities

    • 36 CQ Zones

  • Best DX with G5RV Jr.

    • Scarborough Reef - BS7H (20M CW)

    • Andaman Is. - VU4AN/VU3SIG (20M SSB)

    • Chalogos - VQ9JC (20M CW)

    • Peter I - 3Y0X (40M SSB)

    • St. Brandon - 3B7C (20M CW)

AE6RR – Clandestine Antennas

Relative performance
Relative Performance

  • You will be a Little Pistol Station

    • You will not hear all of the stations that the Big Guns hear

    • You will hear a lot of RFI

    • If you wait for the best propagation, you have a chance

    • CW and PSK-31 will help

    • When conditions are good, you will hear a lot of DX

    • Sunspots help…

AE6RR – Clandestine Antennas


The WAE Award

How to “Work All Electronics” in your house

AE6RR – Clandestine Antennas

Receiving rfi
Receiving RFI

  • You will hear most of the electronics in your house

    • TV sets

    • Computer networks, routers, etc.

    • Switching type wall warts

    • Battery chargers

  • Ferrites may help on some devices

  • In a pinch you may need to turn things off to work that “rare one”

    • Identify the culprits ahead of time

AE6RR – Clandestine Antennas

Transmitted rfi
Transmitted RFI

  • Worst RFI receivers

    • Phones, cordless and regular, answering machines

      • 5 GHz cordless phones seem to be better

    • Home Theater amplifiers, stereos, etc

      • Rear channel speaker leads are great antennas

    • X10 Power Line controllers

    • Paper shredders

    • Burglar alarms

    • Sprinkler controllers

  • Check Jim Brown, K9YC’s material on ferrites and applications

    • Filters and ferrites may help

  • QRP (PSK-31 and CW) may be solutions

AE6RR – Clandestine Antennas


Haven’t had enough RFI?

Not for the faint at heart!

AE6RR – Clandestine Antennas

If you must qro be prepared
If You Must QRO – Be Prepared

  • Solve your 100W problems first

  • You may actually destroy some electronics

  • My DOA list @ 1300 W

    • One answering machine ($50)

    • One Ethernet interface for LaserJet Printer ($300)

    • Max power is now 600 W

  • Burglar Alarm

    • Bell would ring at power levels over 300W

    • Solved by a .01uF capacitor

  • Seriously consider RF exposure levels!

    • Limit duty cycle

AE6RR – Clandestine Antennas

Reference material

Reference Material

Good reading and useful antenna information

AE6RR – Clandestine Antennas

Some good books on stealth clandestine antennas
Some Good Books on Stealth/Clandestine Antennas

  • Stealth Amateur Radio

    • By Kirk Kleinschmidt, NT0Z

    • ARRL Publications

  • Low Profile Amateur Radio

    • By Al Brogdon, W1AB

    • ARRL Publications

  • ARRL Antenna Book

    • Edited by Dean Straw, N6BV

AE6RR – Clandestine Antennas

Good luck good dx

Good Luck & Good DX

de AE6RR

AE6RR – Clandestine Antennas