---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 06/04/19: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:58 AM - Re: Antenna Ground Plane () 2. 09:00 AM - Re: Antenna Ground Plane (Robert L. Nuckolls, III) 3. 09:01 AM - Re: Antenna Ground Plane (Robert L. Nuckolls, III) 4. 10:04 AM - Re: Antenna Ground Plane (Robert L. Nuckolls, III) 5. 01:31 PM - Re: AeroElectric-List Digest: 1 Msgs - 05/28/19 (Scott A Klemptner) ________________________________ Message 1 _____________________________________ Time: 05:58:32 AM PST US From: Subject: RE: AeroElectric-List: Antenna Ground Plane Think I just figured it out, it is the one with 2 V shapes. One leg 7.3 inches and one 22.5 as per www.matronics.com/forums/viewtopic.php?t-222&highlight=&sid=23bc0da12eeb24 ba261ca5ac45ec04b3 Thanks again for the help Mike The antenna is two dipoles . . . one centered on 121.5 MHz, the other on 402 MHz. You have lost me here, I do not understand two dipoles concept. Please explain in more detail if you don't mind Thanks Mike Virus-free. www.avast.com --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 2 _____________________________________ Time: 09:00:13 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Antenna Ground Plane At 12:57 AM 6/4/2019, you wrote: >I am working on an antenna for a homebuilt and I read from the >AEROLECTRIC column in KITPLANES about using ferrite toroid's for a >balun arrangement. However, I seem to remember that the material >used in the toroids must be of a certain mixture to get the desired >effect for RF signals. Can anyone tell me which toroids to use and >which ones not to use. Apparently some work for RF and some work >better for audio frequencies. I included Jim Weir's string-of-beads concept in the 'Connection many moons ago . . . the idea was intuitively logical but physically flawed. That fact was not discovered until a years later when I was working some EMC issues at RAC/Beech and gained access to the EMC lab. I did some testing of Jim's string-of-beads design and found that the differences to be barely perceptible for beads-on versus beads-off. As mentioned in an earlier post, a single toroid with multiple passes through the core is many times more effective . . . however . . . It is true that the material from which the toroid is molded should be optimized for the frequency of interest . . . in the case of the glideslope antenna illustrated in the 'Connection, the toroids should demonstrate good performance at 300+ Mhz. Looking through the various manufacturer's catalogs for toroids, we find very few recommended for service above 100Mhz with most at 30Mhz and below. The antenna chapter needs some work and the string-of- beads idea is going to be removed. What kind of antenna are you contemplating a need for a balun? Bob . . . ________________________________ Message 3 _____________________________________ Time: 09:01:44 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Antenna Ground Plane At 07:56 AM 6/4/2019, you wrote: > > >Think I just figured it out, it is the one >with 2 V shapes. One leg 7.3 inches and one 22.5 as per . . . You got it . . . Bob . . . ________________________________ Message 4 _____________________________________ Time: 10:04:05 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Antenna Ground Plane I did some testing of Jim's string-of-beads design and found that the differences to be barely perceptible for beads-on versus beads-off. As mentioned in an earlier post, a single toroid with multiple passes through the core is many times more effective . . . however . . . Did some digging in the archives and I think these (or very similar) cores were used in Jim's kit: https://tinyurl.com/y2laaf78 This is Type 52 material which offers pretty good performance up to 300Mhz . . . but it still takes a LOT of cores for an effective implementation of string-of-beads. A multi-pass common mode choke could be implemented with a small diameter feedline (like RG174) through the center of this one https://tinyurl.com/y58fqdlh This might be suited for de-coupling the feedline on the dual-dipole ELT antenna. Bob . . . ________________________________ Message 5 _____________________________________ Time: 01:31:38 PM PST US Subject: AeroElectric-List: Re: AeroElectric-List Digest: 1 Msgs - 05/28/19 From: Scott A Klemptner aSBzdWJzY3JpYmUgdG8gMyBsaXN0IGRpZ2VzdHMuaSBoYXZlIG5vdCByZWNlaXZlZCBhbnkgZGln ZXN0cyBzaW5jZSA1LzI4LzE5LmkgY2hlY2tlZCBvbmxpbmUgdXNpbmcgdGhlIHN1YnNjcmlwdGlv biB0b29sIGFuZCBhbSBzdGlsbCBzdWJzY3JpYmVkIHRvIHRoZSAzIGxpc3RzLmFueW9uZSBrbm93 IGlmIHRoZXJlIGlzIGEgcHJvYmxlbSBvciB3aGF0IG15IG5leHQgc3RlcCBtaWdodCBiZT90aGFu a3NzY290dApudWxs ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.