[Antennas] All You Ever Wanted To Know About A Hustler 5-BTV Vertical !
David W Sher
[email protected]
2003年2月26日 04:11:30 -0600
Re your statement "Being retired all I have is time and more time." You
must be single!
Dave W9LYA
What wrought doG hath?
On 2003年2月26日 00:15:14 -0600 Don Schaefer <[email protected]> writes:
>> 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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