In one of Beverage's old articles, there is a page or two devoted to adding coils to lower the velocity of the antenna. If I recall correctly, it has both theory and measurements.
Chuck ________________________________ From: Topband <[email protected]> on behalf of Mikek <[email protected]> Sent: Thursday, November 21, 2019 12:13 PM To: [email protected] <[email protected]> Subject: Topband: BOG Beverage on Ground Help Hi guys, Just saw this page and it presented info that a BOG is a resonant antenna. It gives me a little boost about adding inductance to the antenna to artificially lengthen it. > http://www.iv3prk.it/bog-modeling.htm Is there any agreement about this or anyone want to shoot it down? Mikek Hi guys, I see certain measurements for the length of a BOG, such as 200ft for for 160 meters. And even a warning on one page, /* "The biggest mistake is making the BOG antenna too long. Try not to go */ /*over 200 feet for 160 meters." */So, if I tried to use this 200ft BOG on 80 Meters, I assume it has receive problems. A short explanation of those problems would be helpful, Impedance? Pattern? I've been pondering over W8JI's Loaded beverage page. > https://www.w8ji.com/slinky_and_loaded_beverages.htm I'd like to apply the loading to a BOG to slow the VF and make it seems longer. ie. make a 80 meter BOG length work on 160 Meters. But then make the reactance go away for 80 Meters My actual goal is to have a BOG that covers 500kHz to 4MHz. To that end, I have been working on a variable inductor that I can insert into the length of the BOG. In reality, it would be eight Variable inductors spaced about 35 to 40ft apart. I'm land limited to about 270ft. I want to control the inductors with a DC current through the BOG wire. I have a 100uh toroid inductor that I can partially saturate with an electromagnet. The electromagnet is energized by an adjustable current through the BOG wire. This means I need to RF bypass the Electromagnet, so it's inductance is not seen by the RF. Also I must block the RF from seeing the Power supply/current source. I have a drawing showing my proposed circuit here. > https://www.dropbox.com/s/wrfpubqvsfd11nq/bog%20with%20variable%20inductors..jpg?dl=0 I want to be told what problems you see and ways to overcome them. _If it is at all feasible_, I would wonder about the values of the blocking caps and Chokes. I appreciate any thought you can give this idea. Mikek _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
