Topband: best core material?

[James Rodenkirch]

Yes, JC - ordering 73 material binocular cores today! 
 
> From: n4is at comcast.net
> To: rodenkirch_llc at msn.com; tshoppa at wmata.com; magoo at isp.ca; topband at contesting.com
> Date: Mon, 5 Aug 2013 15:49:37 -0400
> Subject: Re: Topband: best core material?
> 
> 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 at contesting.com] On Behalf Of James
> Rodenkirch
> Sent: Monday, August 05, 2013 2:20 PM
> To: Shoppa, Tim; BY THE LAKE; topband at 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 at wmata.com
> > To: rodenkirch_llc at msn.com; magoo at isp.ca; topband at 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 at contesting.com] On Behalf Of 
> > James Rodenkirch
> > Sent: Monday, August 05, 2013 2:04 PM
> > To: BY THE LAKE; topband at 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 at isp.ca
> > > To: rodenkirch_llc at 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 at msn.com>
> > > To: <topband at 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
> > > >
> > > >
> > > >
> > > > _________________
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> > > >
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