Topband: BOG/close to ground antenna survey.
k1fz at verizon.net
Thu Feb 8 14:48:56 EST 2007
Nine replies were received. The reply from Jon AA1K has been on the reflector. Thank you Jon, and to all that answered de Bruce-K1FZ
Earl, K6SE was the only one making exact termination test on his 7' above the ground Beverages. He is using AWG 17 galvanized steel electric fence wire.
The longest (1100 FT) achieving a 60 db front-to-back and a 60-db front-to-side. He did not achieve the same resilts with copper wire so went back to galvanized.
He used the H.H. Beverage method to find the proper termination.
Gary, K9AY Two of his Beverages are BOGS that he raises up to 30" posts on contest weekends. He sees more than 10 db signal increase in the raised position.
His BOG wire is insulated #12 and terminates with 280 ohms. They require a preamplifier in the down position He has experimented with optimum lengths
for his local conditions- 550 ft and 850 ft have good F/B and deep side nulls.
Rick, N6RK has them at 2-4 feet above ground. Wires longer than 500' are a waste of wire. They work better than 10 foot ones, a low dipole, and
somewhat better than a 4 square. They are very directional and at six is needed to cover all directions.
Terminations were 450 ohms into 6 wire ground radials.
Bill, VE3CSK is using an 475 Ft Beverage 30" above ground terminated into 475 Ohms. The VSWR is above 1:1 but stable from 1.6 to 20 MHz.
It hears almost as well as his 8.5 ' above ground one, and is quieter. Wire is #17 galvanized (electric fence type).
Paul N1BUG has tried 300, 500, 700 foot BOGS. In reality 1-2 inches above ground due to forest floor debris. He is experimenting with termination resistors.
They are not as good as ones 2 to 3 meters above the ground. Front to back only improves slightly when terminated, but is getting at least 20db.
Jack, W0UCE has two sets of BOGS. (45, 280 degrees) Both sometimes work better than his 4SQ Active Array, depending on incoming angle.
The BOG are always better than his K9AY loop (in favored direction).
Floyd K8AC has been using a BOG for a couple of years. Wire is a twisted pair of # 33 Teflon insulated. Thinks it was a 200 ohm termination.
In its favored direction, is hears better than a K9AY, inverted L on 160. and better than other antennas on 80 meters.
Would put up more if he had the space.
Bob AA6VB has #14 insulated laid directly on the grass ground, not terminated. Length 400-600 feet depending upon the day.
Does not hear as well as his coaxial loop and does not think it worth having.
More information about the Topband