If you plan to use the antenna on 160m you'll need 73 material. 43 works 3.8
up.
Regards
JC
N4IS
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of James
Rodenkirch
Sent: Monday, August 05, 2013 2:20 PM
To: Shoppa, Tim; BY THE LAKE; topband@contesting.com
Subject: Re: Topband: best core material?
I wasn't going to use a binocular core, Tim - I was going to use the Amidon
FT-140-43 OR the FT-140-77 IF it made any noticeable difference....is there
some magical reason to use binocular vice standard "round"?
> From: tshoppa@wmata.com
> To: rodenkirch_llc@msn.com; magoo@isp.ca; topband@contesting.com
> Subject: RE: Topband: best core material?
> Date: Mon, 5 Aug 2013 18:12:48 +0000
>
> If receive only, you will do just fine using the 2873000202 binocular 73
material core that Tom mentions.
>
> I think this corresponds to Amidon part number BN-202-73. Newark stocks
the part under the original Fair-Rite 2873000202 number.
>
> Tom shows 2:5 ratio but I've done other ratios just fine.
>
> I am very very impressed with the 2873000202 core, in fact I also use
> it in some DC-DC converters and the core just barely gets warm at the
> 10 watt level. Whenever I've accidentally transmitted into my receive
> antenna, the transformer survives just fine, it's the terminating
> resistor that goes up in smoke. I try not to make a habit of it :-)
>
> Tim N3QE
>
> -----Original Message-----
> From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of
> James Rodenkirch
> Sent: Monday, August 05, 2013 2:04 PM
> To: BY THE LAKE; topband@contesting.com
> Subject: Re: Topband: best core material?
>
> Sorry - didn't make it crystal clear that this is a Delta shaped variant
of a EWE antenna!!!!
>
> My bad for not utilizing all of the necessary verbiage to make that
clear....you see it in ON4UN's latest book on page 7-104.
>
>
>
>
> > From: magoo@isp.ca
> > To: rodenkirch_llc@msn.com
> > Subject: Re: Topband: best core material?
> > Date: Mon, 5 Aug 2013 14:00:48 -0400
> >
> > A full-wave delta loop would have the transformation done with a 1/4
> > wave line of 75 ohm cable. This must be something other than a full-wave
loop?
> >
> > Bill VE3NH
> > ----- Original Message -----
> > From: "James Rodenkirch" <rodenkirch_llc@msn.com>
> > To: <topband@contesting.com>
> > Sent: Monday, August 05, 2013 1:33 PM
> > Subject: Topband: best core material?
> >
> >
> > >
> > > I have a schematic for a delta shaped loop that shows I'll need an
> > > 18:1 transformer to transform the 950 ohms of the antenna to 50
> > > ohms (feeding it with 50 ohm coax).
> > >
> > > One transformer diagram shows an FT-140-43 core being used.
> > >
> > > BUT, looking over some of Tom's, W8JI, write-ups, I see where he
> > > uses 73 material instead.
> > >
> > > I see where 77 material replaced 73 material so -- is an FT-140-77
> > > the mo betta way to go?
> > >
> > >
> > > Thanks, in advance, for any advice/info. Jim Rodenkirch K9JWV
> > >
> > >
> > >
> > > _________________
> > > Topband Reflector
> > >
> > >
> > > -----
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> > > 08/05/13
> > >
> >
> >
> >
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>
> _________________
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