320 likes | 387 Views
Purposes of the Amateur Radio Service. (a) Recognition and enhancement of the value of the amateur service to the public as a voluntary noncommercial communication service, particularly with respect to providing emergency communications.
E N D
Purposes of the Amateur Radio Service • (a) Recognition and enhancement of the value of the amateur service to the public as a voluntary noncommercial communication service, particularly with respect to providing emergency communications. • (b) Continuation and extension of the amateur's proven ability to contribute to the advancement of the radio art. • (c) Encouragement and improvement of the amateur service through rules which provide for advancing skills in both the communications and technical phases of the art. • (d) Expansion of the existing reservoir within the amateur radio service of trained operators, technicians, and electronics experts. • (e) Continuation and extension of the amateur's unique ability to enhance international goodwill.
Who is this W5WZ? • Licensed in 1997 at age 26 (tnx W5LA) • Competitive desire to operate instilled (tnx KM5YL, W5LA) • Contesting spark ignited at FD 1998 (tnx W5EW) • Technical abilities challenged & stretched (thanks K5RUS, K5ER) • The recent shack at W5WZ
My station has evolved just a bit… KD5CAS station circa April 1998 (and only a single ladder-line fed dipole antenna & antenna tuner)
And just for fun… • This is KF5GDK, ten years before earning his license. • He was calling “DQ, DQ!”
Beverage Antenna for Dummies by W5WZ (also a dummy)
Disclaimer: There are smarter guys than me, read their stuff • The ARRL Antenna Book • Lots of antenna info • Chapter on Long-Wire and Traveling Wave Antennas
Disclaimer: There are smarter guys than me, read their stuff • Low-Band DXing by ON4UN • Complete chapter on Beverage receive antenna
Antenna Gain & Directivity • Yagis are directive, i.e. there is less gain in all but forward directions • Dipoles are also directive – broadside in 2 directions • Inverted-Vees are also directive - although omni-directional
The Challenge • Multi-element Yagi transmit and receive antenna are readily available for 10, 15, 20, & 40 meters • Tower height and structural requirements for larger directional antennas (40 & especially 80 & 160) gets complex and expensive • We all want to work more stations on every band, including 160, 80, & 40
Common Situation • Ham station with wire antenna (usually dipoles) on 160, 80, and sometimes 40 • Constraints limit having 160m 3-element at 320 ft & 80m 4-element at 240 ft • $$$ • YL of the house • Neighbors, landlords, size of lot, etc. • Fear of extreme heights • You still want to work lots of stations on these bands
Overcoming the Challenge within the Constraints • If you can’t increase transmit and receive gain, then increase receive directivity • Beverage antenna are ideal solution • Cheap to build • Simple to erect; one person can do it! • Can be temporary: string the wire for a single contest or the winter season • The dB gained are in Signal-to-Noise ratio, in a particular direction
Meet the Beverage • A travelling wave antenna made of a length of wire a small height above earth • Terminated for unidirectional reception • Un-terminated for bi-directional reception.
Practical Considerations • Beverage antenna • Have excellent directivity • Gain usually never exceeds -3dBi • Generally, longer Beverages have lower elevation angles and narrower beam widths • Resulting Benefit: Much higher Signal-to-Noise ratio in the desired direction
In the Real World • Imagine a W1 working Europe on a vertical antenna with thunderstorms in W4-land • Instead of S7 signal with S9+10dB noise on the vertical, perhaps S5 signal with only S3 noise and interference on the Beverage
What Do I Need to Build It? • Length of wire • Supports and insulators • 2 ground rods and clamps • Termination resistors (Ohmite 296-2368, 470 ohm, 2 watt, flame-proof non-inductive, $1.03 from Allied Electronics) • Feed-Point transformer (9:1) • Store bought • Homebrew • Feed line to your receiver
Most of the Hardware • F-connectors & install tool • Transformers • Ground rod clamps • Resistors • Antenna switch
Supports & Ground Rods • Remember to insulate the wire from the support • Trees • T-posts • Bamboo sticks, 4x4s, etc • Standard copper-clad ground rods and bronze clamps
Feed-Point Transformer • Amidon FT-114-43 cost $2.25 each • AWG# 26 spool cost $4.50 • Needs a simple 8-turn trifilar winding for ON4UN design
Another Feed Point Transformer • W8JI design – see W8JI.com • BN-73-202 cost $0.50 each • I find the design by W8JI much easier to wind and implement 2-turn primary 5-turn secondary for 75 ohm feed line (6-turns for 50 ohm) Test by placing 470 ohms across secondary, sweep SWR from 1.5 to 10 MHz – should be flat around 1.2 – 1.4:1
Feed Point • Feed line connectors • Weather proof enclosure
Connect to your Receiver • Coax feed line • 75 or 50 ohm • Modify your transformer to accommodate • Protect your receiver while transmitting, especially if QRO with both transmit and receive antenna in close proximity • “Front-end saver”, CQ magazine, Feb 1997, pages 32-33.
Termination Point • 5-ft ground rod and clamp • Insulator • Wire-nut method to replace resistor without soldering out in the woods
Feb 2010 - Initial Result at W5WZ • Single-wire 285-ft beverage at 45 degrees, average height about 4.5 feet • Just before local sunset, first evening on 80m CW, transmitting 100 watts on dipole at 75-ft, I worked • Z31 - Macedonia • LZ - Bulgaria • YO – Romania In the previous 12 years of hamming, outside of NA I had only confirmed Canary Islands, Cyprus, Morocco, and Suriname on 80 meters
Expanding the Beverage System • Add length to the Europe beverage • Build additional antenna for specific directions – ham population centers • Create/install switching scheme • Provide receive antenna signal to both radios simultaneously
Benefit of Adding Length for 80 meters • A picture is worth 1,000 words
Benefit of Adding Length for 160 meters • Length REALLY matters on 160m!
Benefit of Additional Directions • Ever try to rotate a 500 foot long antenna? • Pull up posts, move termination point, reinstall posts and termination point. • Use a standard multi-position antenna switch to select different beverage and thus heading.
Aerial Overview • 580 ft beverage at 45 degrees (Europe) • 480 ft beverage at 90 degrees (Africa) • 800 ft beverage at 270 degrees (VK/ZL) • 480 ft beverage at 315 degrees (Japan)
Provide Signal to Both Receivers • The “Magic Tee” http://michaelgellis.tripod.com/magict.html • The advantage of the "magic tee" is that the two output ports are isolated from each other and the theoretical loss is only 3 dB.
How to Build the Magic Tee • For 50 ohm coax, change the resistor to 25 ohms • Be SURE to use the right mix of ferrite in the binocular core. • 73 mix is SUPERIOR • Five bucks for 10 binocular toroids • http://toroids.info/BN-73-202.php • http://kitsandparts.com/ • Use a 7 turn primary, and a 10 turn center-tapped secondary. • The sigs will be 180 degrees out of phase • OR, you can buy the $50 DX Engineering box...