[Antennas] All You Ever Wanted To Know About A Hustler 5-BTV Vertical !

[Don Schaefer]

List Members;

At the request of Bob K7LAY ,  I have been asked to summarize all the 
information on decoupleing this antenna
from the transmission line.  It is with a lot of apprehension that I try 
this task, I can only hope to do justice to all
who got back with me on my question. So here goes.

I will not pass judgment on the information I got, but I will be trying 
a number of the ideas to see which works
best for me.

1:  Burying the feedline is reported to serve as a way to decouple.  To 
do this you would have to buy burial-rated coax,
or put it inside a piece of hose.  The idea being to run the coax under 
ground perhaps a quarter wave at the lowest band.

2:  Use Fair-Rite RF beads on 1/4 wave lines  One source for beads would 
be from Mouser Electronics their
part # 623-2643102002 to order Fair-rite EMI Shield Beads for 
RG-8/RG-213 suggested to order six each for
80 - 10 meter choke effect.

3:  The claim that the shield of the coax can sub for a radial system is 
"pure hogwash".  There is no substitute of a good radial system under a 
vertical antenna.   But at the same time ferrite beads properly 
installed and of the right "mix" will do nicely in preventing rf from 
"running down the outside"  of the coax.

4:  Use Radio Works (804-484-0140) type  4KV-L1 Line Isolator.  These 
units are lightweight compared to coax,
and work 100% to isolate the feedline.  160m through to 10m, and are 
inexpensive too.  Sure beats that awkward
"roll of coax" choke.

5:  CHeck at Radio Shack to see if they have the size of snap on beads 
that will fit... and use them.  Or just
wind a choke out of coax at the base of the antenna using several turns 
of RG-8X  using a round can such as
a coffee or Quaker Oats, and wind 6-8 turns, tape it up so it stays 
wound and that should do it.  Always try to connect cables at horizontal 
 points, that way water will not have a place to stand and ingress into 
the joint.

6:   Beads will work fine also. you can order them direct from Amidon at

http://www.amidon-inductive.com/associates_prod_chokes.htm

or check out the Radio works chokes already made up at http://www.radioworks
com/hpcatalog.html Look under line isolators. Also there are others who sell
the w2du choke which also works well..  But the 6" coil will do the job. on
most frequencies.

7:  I would ignore what they recommend as far as the de-coupling. I have 
never done that

and never had a problem. I would attach a SO-239 connector to the base no 
matter what else you do.

I would also add as many radials as you can possibly lay down! The more the 

8: I have a 6BTV which started out as a 4 BTV and grew.  I don't use a 1:1 
balun at the base as my antenna doesn't seem to need it; however, I bury my 
coax in a PVC water pipe for about 25 ft to the point where it goes into 
the house.  If you find you have RF on the coax, a 1:1 balun using beads 
works fine.  Palomar, who advertises in some issues of QST, has balun kits 
of beads for RG-8 and RG-58 coax.  I use an lightning arrestor at the base, 
and connectors are weather proofed using antenna "gunk."  The EMI beads are 
probably not the optimum material for the HF band.   It would take some 
research to locate and identify the correct ones, I don't have the 
information at my finger tips.  Just order a completed commercial 1:1 balun 
or buy a kit from Palomar.  The coax coil, while not as effective as a 
ferrite bead balun, is probably good enough for the levels you will experience.


9: I've been using a Hustler 6-BTV vertical and I installed it exactly as
Hustler indicated in their installation instructions, with coils at each end
of the transmission line.   This method works very well for me and several
other nearby operators who, like you, have either 4-BTV or 5-BTV antennas.
There is no hard and fast rule for constructing the decoupling chokes, and
you can make the chokes a separate item, with connectors at each end if you
wish.  If you do it as a separate choke at the antenna end of the
transmission line, I'd recommend using good quality connectors, either 'UHF'
or 'N', filled with a dielectric water proofing filler called 'STUF', and
wrap the connectors with one of the compounds available from AES or HRO.
Try to keep the number of additional connections to a minimum to reduce
losses.  You don't have to enclose the choke in a box, but I'd protect it
against wild critters that like to munch on cables...

As for substituting ferrite cores for the 6 inch coils, you might want to
ask for some technical help at Hustler.  I have considered using ferrite
cores in place of the coils, but decided not to do so after adding up the
$$$$ for all of the cores.  A length of cable, a few connectors, and some
good quality 3M outdoor electrical tape, is a heck of lot less expensive.
Hustler's coil method works very well to keep RF out of the shack, and also
to keep the transmission line from radiating.

What are you considering as radials?   You can make the 5-BTV work with the
minimum number listed in the installation instructions, but adding more
FULLY INSULATED radials will improve the bandwidth and radiation pattern.
Read the instructions and make sure to insulate the outer ends of each
radial wire.  Home Depot, Sears, Lowes, and most local hardware stores sell
liquid tape, an insulating compound that is available in small cans with an
applicator brush inside the cap.  When you make up your radials, simply dip
the outer end in the insulating liquid and let it dry.  You might want to
crimp ring lugs on the inner ends of the radials to allow more radials to be
attached to the antenna base.  I recommend brushing some insulating liquid
on the junctions of the inner radials and the crimp lugs to avoid corrosion.
Home Depot sells #12 AWG and #14 AWG insulated wire by the roll (either 250
or 500 feet...?).  This wire makes excellent radials for burial, and accepts
the liquid tape very well.  The radials need to be approximately the lengths
indicated by Hustler, and you can lay them out in any manner you can fit
into the available space.  They do NOT need to be straight, but it helps if
they are.   As a reference, broadcasters use as many as 120 radials, 3
degrees apart.  You don't have to use that many, but you might want to
consider using more than Hustler recommends in their instruction sheet...

10: I have a 5-BTV and it works really well for me, ground mounted with 10
tuned radials, 2 on each band. I use it when I go camping and always
get great reports, I wish I had the space to set it up at home.

I use a 4" PVC pipe as a form, about 10" long and have about 10~12
turns of the coax on it, I have one of these on each end of the coax.

here is a link that might help you.
http://www.k1ttt.net/technote/airbalun.html  although it is a bit
technical for most of us including me, if you look past the techstuff
to the basic design you will find that a piece of pvc pipe, some coax
and some vodoo magic will make things work just fine.

I hope that responding to Bob K7LAY request will not cause a great uproar,
but maybe bring some more discussion on the subject.  I again want to thank
all of you list members for your help and like I said earlier I will be trying a number of and or combinations of to find my best results.  Being
retired all I have is time and more time.

Thanks Again
73
Don Schaefer
Spring, Texas



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