Topband: best core material?

[Charlie Cunningham]

BTW, Jim

I think you will be pleased with that loop!  Mine was 40' long X 10' high
and it was an excellent receive antenna for 160, 80, 40 and 30 m. If  you
model it in EZNEC, you will find that the impedances and cardioid patterns
stay fairly constant as you go higher in frequency, but the gain goes  up
with  increasing frequency.  It helped me to hear and work Kazakhstan on
80m, when I couldn't copy on the 80m GP. It opened lots of additional paths
on 160 as well.

73,
Charlie, K4OTV


-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of James
Rodenkirch
Sent: Monday, August 05, 2013 2:29 PM
To: Charlie Cunningham; 'BY THE LAKE'; topband at contesting.com
Subject: Re: Topband: best core material?

Yes to both, Charlie - a friend of mine has a calculator to figure the exact
turns ratio BUT, at a web site I found for this antenna (used during an FO0
dxpedition) the ratio was defined as 8 turns in the primary,  28 turns in
the secondary (for 75 ohm cable so for 50 ohms it'll be something else but
still fairly close to your mentioned 4:1 ratio)

> From: charlie-cunningham at nc.rr.com
> To: rodenkirch_llc at msn.com; magoo at isp.ca; topband at contesting.com
> Date: Mon, 5 Aug 2013 14:24:05 -0400
> Subject: Re: Topband: best core material?
> 
> BTW, Jim
> 
> I assume that 18:1 is the impedance ratio, and the turns ratio is of the
> order of 4:1 or so
> 
> Charlie, K4OTV
> 
> -----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
> > >
> > >
> > >
> > > _________________
> > > Topband Reflector
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