stealth antennas david treharne n8hku march 10, 2005
TRANSCRIPT
![Page 1: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/1.jpg)
Stealth Antennas
David Treharne
N8HKU
March 10, 2005
![Page 2: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/2.jpg)
Introduction
• Most Hams
want a large antenna
• Most don’t get one.
5-band-10/12/15/17/20 Meters, 11 Elements.
Price: $1159.95
![Page 3: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/3.jpg)
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
![Page 4: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/4.jpg)
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
![Page 5: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/5.jpg)
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
![Page 6: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/6.jpg)
The N8HKU Condo
• No outside antennas
• Antennas covering 10m-80m, 144, 440 MHz
![Page 7: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/7.jpg)
The Condo Antenna Farm
• SPI-RO trap dipole for 10-20M
• Isotron combo antennas for 40M and 80M
• Cushcraft Ringo Ranger 2m/70cm Vertical
![Page 8: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/8.jpg)
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
![Page 9: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/9.jpg)
Resonance of Dipole
after Trimming
No tuner needed for 20m. Other bands can be tuned, including WARC bands of 12M and 17M.
![Page 10: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/10.jpg)
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
![Page 11: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/11.jpg)
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
![Page 12: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/12.jpg)
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
![Page 13: Stealth Antennas David Treharne N8HKU March 10, 2005](https://reader036.vdocuments.net/reader036/viewer/2022062314/56649dba5503460f94aab46b/html5/thumbnails/13.jpg)
Resources
• ARRLWeb: Putting Up Your First Antenna Simple antennas for HF and VHF -- and simple instructions for putting them up!http://www.arrl.org/tis/info/antbegin.html 2002-02-05, 8498 bytes
• ARRLWeb: Limited Space and Indoor Antennas
– techniques for building and using limited-space and indoor antennas.http://www.arrl.org/tis/info/limited.html
• 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.http://www.arrl.org/tis/info/antind.html