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:[email protected]] On Behalf Of James Rodenkirch Sent: Monday, August 05, 2013 2:29 PM To: Charlie Cunningham; 'BY THE LAKE'; [email protected] 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: [email protected] > To: [email protected]; [email protected]; [email protected] > 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:[email protected]] On Behalf Of James > Rodenkirch > Sent: Monday, August 05, 2013 2:04 PM > To: BY THE LAKE; [email protected] > 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: [email protected] > > To: [email protected] > > 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" <[email protected]> > > To: <[email protected]> > > 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 > > > > > > > > > ----- > > > No virus found in this message. > > > Checked by AVG - www.avg.com > > > Version: 2013.0.3392 / Virus Database: 3209/6552 - Release Date: > 08/05/13 > > > > > > > > > > > ----- > > No virus found in this message. > > Checked by AVG - www.avg.com > > Version: 2013.0.3392 / Virus Database: 3209/6552 - Release Date: 08/05/13 > > > > _________________ > Topband Reflector > > _________________ > Topband Reflector _________________ Topband Reflector _________________ Topband Reflector
