Re: [Elecraft] OT: Feedline Question

Yes, just like the bio (https://qrz.com/db/N7WS) says; been here 70 years. I like to say I was conceived here, since my parents met and married in Tucson, but were actually in San Diego when I was born. They moved back when I was a young child and I've never left. No reason to, unless I want

Re: [Elecraft] OT: Feedline Question

Hey, and it looks like you are really in 7-land, Wes! OTOH, I'm the "real W7OX", live in a suburb of Los Angeles and have not lived in 7-land (OR/WA) since 1960; farthest North was Palo Alto when I was at Stanford 1963-65. But 20 years ago we considered retiring to Portland very seriously,

Re: [Elecraft] OT: Feedline Question

I'm cursed. It's bad enough that I've worked (I thought) several stations in DX pileups only to later have the DX say, "Nope, we worked N6WS, not N7WS". Now my work is attributed to him too. (Just kidding Jim) Actually, the article never appeared in QST. Too technical; it went right to

Re: [Elecraft] OT: Feedline Question

What difference does oxidisation make on bare wire, ot tinning?? My feeders are mainly enamelled copper which won't corrode. Does the enamel make a significant difference? Hs anyone done the comparisons? Guy Olinger K2AV wrote: > What you appear to refer to by "open wire

Re: [Elecraft] OT: Feedline Question

On Tue,4/18/2017 11:26 AM, Guy Olinger K2AV wrote: What you appear to refer to by "open wire line" is BARE wire with small spacers widely separated. That's what Wes built to compare with the window line. Most practical implementations of open wire line use much wider spacing. The increased

Re: [Elecraft] OT: Feedline Question

Hi, Jim, What you appear to refer to by "open wire line" is BARE wire with small spacers widely separated. Performance changes a lot if the "open wire line" is constructed with unstripped THHN. Particularly with surface tension on new THHN. Where hung on the level in a misting rain, I have seen a

Re: [Elecraft] OT; Feedline question

And your effort is most sincerely appreciated. :) __ Clay Autery, KY5G On 4/17/2017 10:31 PM, Al Lorona wrote: > This obsessive exercise on my part illustrates that spacers don't make a > whole lot of difference, but they do make a difference. You may want to > include

Re: [Elecraft] OT: Feedline Question

On Tue,4/18/2017 10:10 AM, Guy Olinger K2AV wrote: Then there is the loss based on number of spacers and loss tangent of the spacer material modifying the lesser air loss. Below UHF, loss in transmission line is virtually all due to copper losses unless the dielectric material is wet or is

Re: [Elecraft] OT: Feedline Question

...@sbcglobal.net> > To: "elecraft@mailman.qth.net" <elecraft@mailman.qth.net> > Subject: Re: [Elecraft] OT; Feedline question > Message-ID: <852881305.2998918.1492486319...@mail.yahoo.com> > Content-Type: text/plain; charset=UTF-8 > > If instead of using the relativ

[Elecraft] OT: Feedline Question

Message: 4 Date: Tue, 18 Apr 2017 03:31:59 + (UTC) From: Al Lorona <alor...@sbcglobal.net> To: "elecraft@mailman.qth.net" <elecraft@mailman.qth.net> Subject: Re: [Elecraft] OT; Feedline question Message-ID: <852881305.2998918.1492486319...@mail.yahoo.com> Conte

Re: [Elecraft] OT; Feedline question

If instead of using the relative permittivity of air, 1.00059, for calculations of open-wire line, you use the effective permittivity including any spacers used to homebrew the line, this value will increase slightly. For instance, I am using spacers made of a material called "nylon 6,6 30%

Re: [Elecraft] OT; Feedline question

I'll agree with both points. That said, think about the space between wires. On and about the wires is a relatively thin layer of plastic. From there, the space between wires is filled with...wait for it...air. It might be worthwhile to read this: http://k6mhe.com/n7ws/Ladder_Line.pdf On

Re: [Elecraft] OT; Feedline question

Actually thermoplastics are NOT majority air I'm not an expert here, but the dielectric constant appears to increase with thickness and probably with density of the material. Keep in mind that the standard insulation on THHN is 0.015" thermoplastic (PVC) and that is covered by a 3-4 mill

Re: [Elecraft] OT; Feedline question

Why do you suppose a little bit of dielectric on the wire would make a huge change, when the majority of dielectric is still air? On 4/15/2017 3:56 PM, Clay Autery wrote: Thanks So, these numbers are for BARE copper, right? Using insulated wire changes things a bunch For instance 18

Re: [Elecraft] OT; Feedline question

I don't think you're missing anything. It was a good question. Please also see Clay's reply. 73, matt W6NIA On 4/15/2017 4:08 PM, Richard Fjeld wrote: Okay, and thanks to all for the info which I will save. What made me curious is that twin lead is stated in steps of 150 ohms. IE. 300,

Re: [Elecraft] OT; Feedline question

I was trying to find the dielectric constant (Epsilon sub r) for this poly jacket that's used on the standard HRO-available line. The calculations I did were for open wire line with air being the dialectric (something like 1.0054). The first ladder line that I used was made from BIC pens,

Re: [Elecraft] OT; Feedline question

Okay, and thanks to all for the info which I will save. What made me curious is that twin lead is stated in steps of 150 ohms. IE. 300, 450, 600. I assumed it was to match the impedance of certain antennas such as a folded dipole, etc. Since I understand my loop to be a non-resonant antenna,

Re: [Elecraft] OT; Feedline question

Thanks So, these numbers are for BARE copper, right? Using insulated wire changes things a bunch For instance 18 GA THHN/THWN has an approx. dc of 2.35, XLPE has a dc of 5 or so As the dielectric constant gets larger, things get real fast. 18 GA THHN/THWN... (dc = 2.35

Re: [Elecraft] OT; Feedline question

Very true! Got back in front of my desktop 'puter and made an Excel worksheet to calculate the characteristic impedance at various spacings and wire sizes. The real variable is the ratio of spacing divided by wire diameter (only the ratio matters). Everything else in the formula is a

Re: [Elecraft] OT; Feedline question

Off-list one person learns. On-list we all learn. On 4/15/2017 10:16 AM, Matt Zilmer wrote: This is an amateur topic, so there's no reason to take it offline, imho. __ Elecraft mailing list Home:

Re: [Elecraft] OT; Feedline question

This is an amateur topic, so there's no reason to take it offline, imho. If you run the impedance vs spacing calculations, you'll see the spacing doesn't make a whale of a lot of difference. I don't have the numbers here, but I switched from 1/2 of a BIC pen body (hole centers about 2" apart)

[Elecraft] OT; Feedline question

Forgive me for the OT, but there are many antenna people here above my pay-grade. I need to replace the spacers on my ladder line. If I deviate from the standard spacer length for impedance (separation between conductors), are there problems I'm not thinking of? I use a quality manual tuner,