Some of those commercially made cheapie 100 watt baluns and transformers are
obviously
nmot made to do the job properly.
On 26 Apr 2015 at 14:08, Kelly Taylor wrote:
> If the choke bead is getting too hot, it doesn't mean you shouldn't use a
> choke. It means the choking impedance isn't high enough. Either the beads
> aren't the proper ferrite material or there aren't enough of them. With many
> commercial bead chokes, it's sometimes a combination of both errors.
>
> If anything, the heat is proof a choke is required, because if that energy
> wasn't making the bead choke hot, it would be on the outside of the
> feedline.
>
> 73, kelly
> ve4xt
>
>
> On 4/26/15 12:51 PM, "Bry Carling" <bcarling@cfl.rr.com> wrote:
>
> > Yes there is no way a monster fan dipole would work here. Small lot. I did
> > try
> > one and it was too obtrusive as well as high SWR on every band contradicting
> > all theory. First I have heard of using any "choke bead" for a G5RV. If it's
> > getting hot then it's wasting a lot of your RF power.
> >
> > Best regards - Brian Carling
> > AF4K Crystals Co.
> > 117 Sterling Pine St.
> > Sanford, FL 32773
> >
> > Tel: +USA 321-262-5471
> >
> >
> >
> >
> >> On Apr 26, 2015, at 12:22 PM, Grant Saviers <grants2@pacbell.net> wrote:
> >>
> >> My G5RV at QRO stopped working when the purchased bead choke at the
> >> coax/ladderline junction got so hot it melted the coax. They need several
> >> thousand ohms of choke impedance, usually not found in most of the off the
> >> shelf bead chokes.
> >>
> >> OTOH two 80/40/20 fan dipoles (at right angles) I modeled and built worked
> >> super at 65' high. They worked on 15m with a tuner (<2.5:1 swr) and
> >> perhaps
> >> on 10m if the coax is cut for a match or there is enough loss. I
> >> separated
> >> the ends by 24" using 3/8 sq pvc rod which makes for mechanical complexity
> >> and difficulty winding it up (I use 10" diameter concrete column forms).
> >> Eznec models are reasonably accurate if you follow the recommendations on
> >> modeling by Cebik, #108-111 at http://www.antennex.com/w4rnl/
> >>
> >> re VE7RF's conjecture that the center of every dipole may not need to be
> >> connected: Since I had a working EZNEC model, I disconnected the
> >> transmission line connections to the 40 and 20m dipoles and fed only the
> >> 80m.
> >> There is coupling but very poor swr; 4:1 on 40m, 10:1 on 20m, 8:1 on 15m,
> >> so
> >> it's not a good idea.
> >>
> >> Grant KZ1W
> >>
> >>> On 4/26/2015 1:26 AM, Steve Hunt wrote:
> >>> The 51ft "G5RV" performs well on 40m, 20m and 10m - bands where the
> >>> SWR(50)
> >>> at the ladderline/coax junction is moderate. On other bands the SWR(50) is
> >>> high, and how well it performs will depend on the length and quality of
> >>> your
> >>> coax run.
> >>>
> >>> On 40m you will notice little difference compared to a half-wave dipole;
> >>> on
> >>> 20m it has a small amount of broadside gain over a half-wave dipole; and
> >>> on
> >>> 10m the azimuth pattern has broken into 6 major lobes, with best
> >>> performance
> >>> at 45 degrees to the direction of the wire
> >>>
> >>> Using a good CM choke at the coax/ladderline junction is important - it
> >>> will
> >>> reduce radiation from the ladderline section and noise pick up on the coax
> >>> run.
> >>>
> >>> Steve G3TXQ
> >>>
> >>>
> >>>> On 25/04/2015 21:11, Dick NY1E wrote:
> >>>> I'm operating from a small lot in Florida winters, I have a 40M dipole up
> >>>> but it doesn't quite fit my opening, it is into the branches 5 or 6
> >>>> feet. I
> >>>> wonder what the 51' G5RV would perform like compared to the dipole on 40,
> >>>> and as a bonus I might get some other bands... Any ideas???de Dick
> >>>> NY1E/4www.ny1e.com
> >>>> _______________________________________________
> >>>>
> >>>>
> >>>>
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> >>
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