Stealth Antennas David Treharne N8HKU March 10, 2005

Introduction Most Hams want a large antenna Most don’t get one. 5-band-10/12/15/17/20 Meters, 11 Elements. Price: $

Why Not? Cost: Antennas and towers are quite expensive. Zoning: Restrictive covenants make it difficult and expensive to put up a large antenna array Space: Many homes/condos/apartments do not have the space Spouse: Beauty is in the eye of the beholder

Solution: Stealth Antennas It turns out that an antenna does not have to be BIG to work It does not have to be outside to work It does not have to be high powered to work It does not have to be permanent to work

What is Needed An attic, a porch, a deck, a flagpole, or even a ceiling A tuner A good set of speakers or headphones Patience An occasional contest

The N8HKU Condo No outside antennas Antennas covering 10m-80m, 144, 440 MHz

The Condo Antenna Farm SPI-RO trap dipole for 10-20M Isotron combo antennas for 40M and 80M Cushcraft Ringo Ranger 2m/70cm Vertical

Getting the Antennas in the Space Trap dipole across the attic, bent to “see” Europe Need to trim them to resonance Metal can interfere with them

Resonance of Dipole after Trimming No tuner needed for 20m. Other bands can be tuned, including WARC bands of 12M and 17M.

Other Antennas Isotron antennas needed significant trimming, and still need tuning. Ringo Ranger had horrible transmission to the Tin Lizzy until I moved it 1 ft over, now great reception

Power May not be a good idea to run full power –Interference potential with home electronics Issue with home stereo –RF Exposure needs to be analyzed for both yourself and for others in the house or in the adjoining units I performed a full analysis –RF can get into your equipment Keyboard acts up on 10m Needed to add an isolation choke between my radio and computer to keep RF out of the speaker system

Where have I worked? United States –40M/80M is within 1,000 miles only due to near vertical sky bounce –Oregon/Washington tough ROW: –Russia, South America, U.K, Germany, Israel, Australia, Finland, Italy, Croatia, Spain, Netherlands, Japan All of that on SSB –Contests help: late in contest, all the Big Guns have been worked, and the operators listen better for the weaker signals Many countries worked on RTTY or PSK 31 as well. –Can use less power –Signals are stronger –Less atmospheric interference

Resources ARRLWeb: Putting Up Your First Antenna Simple antennas for HF and VHF -- and simple instructions for putting them up! , 8498 bytesARRLWeb: Putting Up Your First Antenna ARRLWeb: Limited Space and Indoor Antennas –techniques for building and using limited-space and indoor antennas. The Care and Feeding of a Condo Antenna Farm –The Care and Feeding of a Condo Antenna Farm 64 April 2001 In By Al Alvareztorres, AA1DO ARRLWeb: Antenna - Indoor –techniques for building and using limited-space and indoor antennas.