Guy, Thanks and two initial questions:
1) what are the consequences good or bad if the wire is 2 inches above the ground? 2) any recommendations on a BOG amplifier? Thanks Paul On Sat, 3 Aug 2019 at 23:29, Cecil <[email protected]> wrote: > Guy...a great post! > > Great information for those of us who are looking for RX antenna options > but don’t have the room for the normal RX antennas... > > And also a real breath of fresh air in light of our recent discussions.. > > Thank You! > > Cecil > K5DL > > Sent from my iPad > > > On Aug 3, 2019, at 5:17 PM, Guy Olinger K2AV <[email protected]> wrote: > > > > Hi, Ed, > > > > You're on the right track. > > > > A "beverage" ON the ground really is NOT a beverage. For two things to > be > > called the same genus, they need to have most everything in common. This > is > > true of big yagis, little yagis, short yagis, long yagis, trapped yagis, > > linear loaded yagis, end loaded yagis, moxons, yagis at 30 feet and yagis > > at 200 feet, etc. One program optimizes them all. A yagi is a yagi, is a > > yagi, is a yagi, and all of them have a ton of yagi-ness held in common. > > Simply not so BOG vs. beverage. > > > > Creating beverage advice from one particulars person's wire down close to > > or on the ground at their particular property, may be simply and totally > > wrong for someone else. The normal beverage tuning instructions, usually > OK > > for wires a foot off the ground and maybe even OK to some degree for four > > inches, simply do not apply if the wire is actually laying on the ground. > > > > A regular beverage has a decent RX signal strength. To be truthful, a > > **real** BOG needs a remote amplifier, because its output is way down > from > > a real beverage. Get this much straight: an actual BOG is a LOW output > > antenna, period. The way to improve a BOG's signal output is add an amp > > (best remote), or escape BOG-iness and lift it off the ground. > > > > If you model a real BOG, you find that beyond an ELECTRICAL half wave ON > > THE WIRE, or two hundred something feet on 160, extending the BOG wire > will > > start to REVERSE the pattern. No real beverage ever does that. Just some > > beverage lengths are bit better than others FOR REAL BEVERAGES. A BOG is > a > > single band antenna for optimums. It will hear stuff on other bands, but > > forget a designed pattern like you have on a beverage for several bands, > > that work WELL on several bands. > > > > If you are even two inches above actual ground, laying on top of grass, > you > > are blending the very different worlds of pure BOG and pure beverage. If > > you are at two inches, you are at a poor place to advise either owners of > > pure BOG's or pure beverages. The great problem is that exactly which > type > > you are closer to depends on the vagaries of the location-specific ground > > underneath. > > > > These vagaries wander HUGELY ( I'm talking about an actually carefully > > ****measured**** wandering HUGELY) depending on individual properties. > > Based on those **measurements** it is a normal outcome that one end of > the > > wire could be more BOG and the other end of the same wire could be more > > beverage, and even vary more depending on whether it rained in the last > few > > days (or weeks depending on the local and natural drainage of the soil). > > > > It is clear reading a lot of the posts on BOG's from the last week or > two, > > that a lot of users were expecting greater signal output. Don't. A REAL > > *BOG* that was laid down, notched in the grass down to the actual ground > > surface, to get it out of sight and safe from lawn mowers, WILL sound > MUCH > > better to the ear if it has an amp. Otherwise, a BOG is a LOW LEVEL RX > > antenna. > > > > IN GENERAL, a real BOG needs an amplifier, will usually wind up somewhere > > 180 to 230 feet if you want front to back, and it's great advantage is > that > > it can't be mowed, snagged by galloping deer, have tree branches knock it > > down, be seen by unfriendly neighbors and it will do roughly as well as a > > single direction K9AY, but without the AY's ugly wires above the ground, > IF > > it's amplified. If the feed circuitry is done correctly, a BOG will be > > wonderful at reducing local noise off the sides. > > > > You will increase signal level significantly by getting it up an inch or > > two on top of the grass, but it ain't a pure BOG anymore, the VF is > > increased significantly, and then it needs more length to be optimum at > two > > inches. And you will still not be able to tune it smartly like a beverage > > using SWR to the terminating resistor. > > > > BOGs are a cantankerous RX antenna. You can throw a 250' wire down on top > > of the lawn and take it up after the contest. In normal (not super quiet) > > settings it WILL hear a lot of signals better than the inverted L. Just > > understand that is NOT a design antenna, and was not optimized, did not > > have the best signal to noise of a designed-for-location BOG antenna, and > > was not as good as a beverage. > > > > We know what the issues are, but new-comers to the BOG idea just don't > know > > the vagaries and how to squeeze the best out of on THEIR property. > > > > The category is Ground Low Velocity Factor (GLVF) antennas. DOGs, LOGs > and > > BOGs. If they're up in the air, even two inches, they're likely NOT GLVF. > > GLVF are low output RX antennas. If you are looking for high signal > output > > from the antenna without an amplifier, just forget GLVF. > > > > Been there, done all of that. > > > > 73, Guy K2AV > > > > > >> On Thu, Aug 1, 2019 at 2:57 PM Ed Sawyer <[email protected]> > wrote: > >> > >> Isn't BOG still a beverage just with more ground coupling loss because > its > >> literally "on the ground"? So the typical answer on beverages seems to > be > >> that 4 - 10 ft above the ground is low enough to eliminate the undesired > >> noise but high enough to reduce the losses from being too low to the > >> ground. > >> A BOG is a beverage with higher than desired losses. But if its long > >> enough, pointed in the right direction, and your ground conductivity is > >> accommodating, its less of a trade than the reverse of those items. > >> > >> > >> > >> I have had a few unplanned BOGs that were discovered as "on the ground" > >> because of some supports falling down. I could immediately hear the > >> difference, but they still worked. Would they be usable if that was my > >> only > >> option? Sure. Just not as good as the same wire at 6 - 8 ft. > >> > >> > >> > >> I use 650 - 1000 ft terminated beverages and they are quite amazing. My > >> ground condition is lossy and I don't have much local noise to null out. > >> Its pretty much all atmospheric noise. > >> > >> > >> > >> Ed N1UR > >> > >> _________________ > >> Searchable Archives: http://www.contesting.com/_topband - Topband > >> Reflector > >> > > _________________ > > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
