The MFJ can be a blunt instrument on certain tasks. I'm not sure that the 259 is a good instrument for measuring zero Z crossings. What I used to do before I got better stuff, was to sweep the freque
Lowering Z with more radials is the classic sign of reducing lossy series resistance in the ground system. This is a straight power loss to RF heated dirt which adds to the radiation resistance of th
Whether forested areas absorb vertically polarized radiation is controversial, and personally I have not seen anything convincing either way. Discounting the trees as an issue, adding 16 long radials
There is very little difference in the pattern of a 5/16 inverted L and 1/4 inverted L that has the bend to horizontal at the same height, assuming a bend even roughly half way. The lower the bend th
The actual difference will vary somewhat depending on where the bend is. The simple one I tried had only one degree difference, 25 and 26 degrees, but the difference between the two elevations was on
Given the mentioned, a "tee" shape, with the top of the tee used as a pair of radials and fed at the junction , the antenna will perform as a too-short bog, IF care is taken to isolate the feedline,
A BOG is an antenna that suffers from incoming waves propagating at the speed of light while propagation along the wire can show a velocity factor from .45 to .80, sometimes varying wildly with place
Reread the email. You trim a BOG to a working length using its DOG-mode resonance. The former is very difficult to measure and involves helicopters. The latter is easier than trimming a dipole, if yo
Have you had the opportunity to actually MEASURE it's pattern other than at the ground? You can get a good front to back and forward pattern on a single band. It's length would not suggest resonance
No, it's not silly. People have buried BOG's in lawns, although "burying" the wire is usually just pushing the wire into a slice into the sod. The wire needs to be insulated and sealed at the end of
Aside from miscellaneous capacitance, which won't amount to much on 160, just changing the feed a little, I don't see any real effect. You should connect the metal house to the radials and to your gr
Small hardline through the woods is one permanent answer to that. Considering how much money we spend on antennas and amplifiers it is sometimes remarkable how cheep we get on feedline, and go nuts a
Hi, Tzikas Short version: Your six elevated 1/8 wave radials at 9 meter height will do better than the plan in your picture with the long 1/4 wave radials in only one direction. Make sure you have a
All of these concerns are just flies on the back of the cow if the ground/radial/counterpoise system is not efficient. OTHERWISE... If you model a lossy ground/radial/counterpoise into the equation a
Various visual mental simplifications of what is going on in inverted L's do not map well with what a model will show if you vary one length, record the results, vary it again, record, etc to create
Primarily in reply to KJ4FDV's post... The way to model ground loss invoked by elevated radials is fairly straight-forward if a couple specific gotchas are avoided, and this can also be factually mea
I own a C31XR and for use on a tower that is used for a 160 vertical, just remove the insulation on the twenty meter reflector and director. There is no change in performance in the XR. I have never
On rotary coils providing an adjustable inductance, the usual way to reduce the inductance is for a moving shorting contact to short to one end. Whether that is the top or not depends on it's use in
Given that BOGS are right at root level, the velocity factor along the BOG wire will be somewhere between 45 and 75%, most often toward the 50% end of the range if it's pushed down good in the grass
Short version: Anyone who has four elevated radials can easily check this out. How to in Long Version. 1/4 wave elevated radials can have 18-60 ohms ground induction loss per radial. Divide by number