Hello John,
It's good to hear from you, and I would love to answer your questions
immediately. However, that is not possible right now. Sorry.
There are lots of great people on the Topband reflector that forgot more than I
know about Beverages, I and I think it would be good if you posted your
questions directly to that list.
I have two editions of Vic Misek's book, and also John Devoldere's Low Band
Dx'ing book. John's (ON4UN) book is far, far better than Misek's book.
BTW, I don't know why Vic uses the core material he does. It's not optimum on
160.
73,
Mike Waters
W0BTU
--- On Sat, 10/17/09, john <jb@beaumonts.karoo.co.uk> wrote:
> From: john <jb@beaumonts.karoo.co.uk>
> Subject: Re: Topband: Wire type in two direction beverage system
> To: "Mike Waters W0BTU" <mrscience65704@yahoo.com>
> Date: Saturday, October 17, 2009, 3:17 AM
> Hi Mike,
>
> I may have made an error in constructing my hardware for
> the two wire beverage.
>
> I have made up some poles 12ft long with a crossarm at the
> top and fixed insulators 12 inches apart so the wires are
> 12inches apart (this may now be wrong) I was taking the info
> from the Beverage Antenna Handbook.
>
> I have bought 2 rolls of electric fence wire it is 7 strand
> ,I think it is about 3mm 0.11 inches
> the antenna can be up to 916ft long I was thinking 880ft.
>
> Some time ago I got some cores MN8CX and bronze clips
> fromVictor Misek W1WCR when I got the handbook he says to
> use nr 30 gauge wire which in England thats 0.25mm so I have
> got some of that and my stainless steel bolts etc and boxes
> to house the transformers in.
>
> Well before I go ahead I wondered if I could ask your
> opinion is maybe the spacing wrong for the wire gauge at a
> ht of 10ft, I have to have this ht because we have 3 ponies
> in the field and sometimes need to take a tractor around it
> too.
>
> Regarding the transformers he seems to have a lot of
> windings on them the feed end transformer is on page 48 and
> reflection transformer is on page 55 but I dont know if you
> have this book.
>
> The thing is the wire gauge he has designed the
> transformers for is half the diameter I am using he uses
> nr14 awg.
>
>
> So I am a bit confused, there was no label on the electric
> fence wire but its 7 strand other people who sell the same
> stuff say its 7 strand of 0.5mm.
>
>
> I really want this antenna to work well and wish to bring
> both feeders into the shack and have only a simple a/b
> switch.
>
> I dont know how critical minor changes are but you say your
> 2 wire beverage works really good.
>
> regards
>
> John G4EIM
>
> ----- Original Message ----- From: "Mike Waters W0BTU"
> <mrscience65704@yahoo.com>
> To: "john" <jb@beaumonts.karoo.co.uk>
> Sent: Wednesday, September 09, 2009 12:20 AM
> Subject: Re: Topband: Wire type in two direction beverage
> system
>
>
> Hi John,
>
> I'm happy to answer your question as best as I can. Sorry
> for the delay in replying.
>
> Yes, I did wind my own reflection transformer. Everything
> about my Beverage is homebrew. All 3 of the transformers,
> including the reflection transformer, are transmission line
> type.
>
> I assume you mean calculate the spacing between the wires.
> I have a spreadsheet I can e-mail you, otherwise you can
> just tell me your wire diameter and I can calculate the
> required spacing for you at 10' high.
>
> 73,
> Mike Waters
> W0BTU
>
>
> --- On Sat, 9/5/09, john <jb@beaumonts.karoo.co.uk>
> wrote:
>
> > From: john <jb@beaumonts.karoo.co.uk>
> > Subject: Re: Topband: Wire type in two direction
> beverage system
> > To: "Mike Waters W0BTU" <mrscience65704@yahoo.com>
> > Date: Saturday, September 5, 2009, 2:01 AM
> > Hi Mike, I read your post re
> > reversible beverage and your fabricate line, did you
> wind
> > your own reflection transformer for this, I am
> planning of
> > installing a reversible beverage but must have it a
> bit
> > higher due to horses lets say 10ft.Could you tell me
> how to
> > calculate spacing for a given diameter of wire if I
> were to
> > use a commercial transformer.
> >
> > regards
> > John G4EIM
> > ----- Original Message ----- From: "Mike Waters
> W0BTU"
> > <mrscience65704@yahoo.com>
> > To: "Toni Lindén" <oh2ua@oh2u.com>;
> > <topband@contesting.com>
> > Sent: Friday, September 04, 2009 10:34 PM
> > Subject: Re: Topband: Wire type in two direction
> beverage
> > system
> >
> >
> >
> > Hello Toni,
> >
> > The impedance of the two-wire line should equal the
> > impedance of the two wires to ground. If they do not,
> then
> > you need to change the ratio of the 1:1 reflection
> (far end)
> > transformer.
> >
> > In your case, you are proposing to use 145 ohm line,
> which
> > at 6 feet above ground has a common mode (both wires
> to
> > ground) impedance of about 480 ohms. You would need
> to
> > change the 1:1 transformer to about 3.33 to 1 for
> optimum
> > performance (F/B ratio) of your Beverage.
> >
> > I fabricated my own open wire line out of plated
> steel
> > electric fence wire, which is very strong. Using the
> known
> > values of (1) the wire diameter and (2) the desired
> height
> > above ground, I then made some plastic spacers with
> two
> > holes 1.10" apart. This spacing made the common mode
> and
> > differential mode (line) impedances nearly equal.
> >
> > The 580' bi-directional Beverage I made from this
> line
> > works absolutely fantastic.
> >
> > 73,
> > Mike Waters
> > W0BTU
> >
> >
> > --- On Fri, 9/4/09, Toni Lindén <oh2ua@oh2u.com>
> > wrote:
> >
> > > From: Toni Lindén <oh2ua@oh2u.com>
> > > Subject: Topband: Wire type in two direction
> beverage
> > system
> > > To: topband@contesting.com
> > > Date: Friday, September 4, 2009, 4:43 AM
> > > Hi all!
> > >
> > >
> > > I'd like to know what kind of a difference the
> > transmission
> > > line impedance
> > > makes in two way beverage system?
> > >
> > > We have DX Engineering (W8JI design) two way
> beverage
> > > system at CU2X. (
> > > http://www.dxengineering.com/pdf/RBS-1%20Rev2.pdf)
> > >
> > > The system is designed for 450ohm ladder line,
> but
> > the
> > > problem is that
> > > ladder line doesn't last in high winds up in our
> QTH.
> > > (I know, there's steel inside but even with
> poles
> > about
> > > 15ft from each
> > > other, the wind load of ladder line is just too
> > much.)
> > >
> > > So my question is, does that two way beverage
> system
> > work
> > > with line having
> > > impedance around 150 oms and if it's not working
> as
> > well as
> > > with 450ohm
> > > line, how big is the difference and in what
> > parameters
> > > we're loosing
> > > ground?
> > >
> > > I'm planning to use the old telephone cable
> instead
> > of
> > > ladder line.
> > > Detailed information about the cable can be
> found
> > here:
> > > http://www.saunalahti.fi/hohtola/ham/killu/killu.html
> > >
> > >
> > > 73 de Toni, OH2UA
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|