Tony
I have used one of these they do work . I had an opportunity to compare
it with a more typical end fed bog of the same length in the same
direction. They are identical in performance . In my situation both
BOG's were installed over very poor ( essentially well drained dry sand).
Pro's
1) easy to install
2) Works as good any "standard BOG" would at your location , when
installed in a similar manor as you would any other BOG ( no better, no
worse, no magic)
3) Easy bidirectional switching
4) Built in receiver protection against high RF levels ( back to back
diodes)
5) Built in� lightening protection
6) Fused protection to keep you from frying the unit if you transmit into it
7) Allows you to experiment with other receiving antennas� such as
Flags, Pennants and standard beverages as well as bogs all from the same
box ( depending on the configuration you must open the end reflection
boxes and move jumpers) As shipped comes default for BOGS and Beverages
8) The feed point can indeed be inserted at ANY point along the antenna
without affecting the performance
Cons
1) Very expensive for what it is, sells for at least 2X what the bill of
material suggests it should ($75-$150 is more realistic price,� IMO)
2) While it comes with stainless hardware, some of it is cheap Chinese
cr#$, Some pieces on mine began showing rust after less than 60 days in
Florida's monsoon climate, Plan of having to replace that at some point
3) IMO the boxes will not remain water tight with repeated closing and
opening to move jumpers etc, based on similar experience with this style
box that I have purchased for other DIY projects. Once you are through
playing, plan on taking more diligent sealing steps once a permanent
installation is decided on
4) The fuse noted in #6 above is an odd package� ( to me anyway) low
current 50ma job in a solder in package. I think I would choose a more
typical cylindrical clip in holder, there is certainly room in the box.
5) The 2way box in the shack is too light ( needs a couple of pounds to
hold it down)
Interesting Info, Hints & Kinks
1) No BOG will work as well� when placed too close to a wire ( chain
link) fence. allow at least 5' set back
2) The basic center fed RG-6 design is right out of Misek, W1WCR's
Beverage Antenna Handbook , 2nd Edition, Page 68
3) Mostly easy to reverse engineer once you have a set in your hands,
not surprisingly they will not supply schematics.
4) The "magic" is in the end "Reflection " Boxes which have selectable
(via the jumper settings)� impedance ratios depending on the antenna
type (BOG, Beverage, Flag, etc) to be used with.
5) Yes I have reverse engineered the the thing ( I pad $$$ for the
ability to do so) and NO I will not share the results directly with you
. I will point out that If you don't need the flexibility of using the
same set of boxes for many different types of receiving antennas then
build a set with reflection boxes for that specific geometry and you
don't need the more complex� jumper selectable box. Again I refer you to
Misek's book for starters.
6) My set is currently on loan to a friend who is trying it out at his
location . IF he decides not to buy it from me it will be available at a
discount from the new price. Dont email me I will let you know if I sell
other than to my friend.
Cu you all in the pile up
Dave
NR1DX
On 11/22/2019 10:12 AM, tony.kaz--- via Topband wrote:
https://static.dxengineering.com/global/images/technicalarticles/ums-bevflex
-4x.pdf
--
Dave
Manuals@ArtekManuals.com
www.ArtekManuals.com
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