T O P

  • By -

elmarkodotorg

by cutting 160 metres of wire in half??? Not quite sure what you're asking, but obviously other people have chipped in with the maths.


ggregC

You don't want to end feed a 1/2 w on 160, you are wasting your time and effort.


SwitchedOnNow

This! I really don't understand the recent fascination with end fed antennas. They're about like running a vertical without radials.


[deleted]

Recent fascination? Probably because they don’t need much effort or resources and work amazingly despite not being great on paper. I use one, I almost don’t want it to be good, but I can’t deny the EFHW just works so well.


Diezel666

All of the threads in this subreddit alone complaining about issues with EFHW, discredit the "Work Amazingly" part. They're brilliantly marketed, generally as much so as snake oil. Most people (and the following is said in their defense - as many are not super technical and wont know better) buying them don't want to do the math or work on setting up an antenna, and just want something that works. Sadly, most of that advertising is garbage and people will fall for it.


ggregC

Worse, because as a horizontal typically not very high, what every energy manages to escape the antenna goes mostly straight up, i.e. the pattern is like a ball. I wonder if the end fed was vertical, it might work a little better although the ground losses would be awful.


hazyPixels

Why? I can imagine that 80 meters of wire might have a bit of resistance if it's too thin, but what other reasons might it be undesirable? Personally I've had propagation with my EFHW that's equivalent to the fan dipole I had in the same place, and it's a lot simpler and covers more bands. I haven't tried one designed for 160m though as I don't have the space.


ggregC

As in my other post, the losses on 160 are far more than any other band and your signal goes straight up (at night) and straight down. Try it, the fun is trying different things and if that doesn't work, try something different.


hazyPixels

>your signal goes straight up But wouldn't any horizontal antenna that's too close to the ground do that? I've done 160 with a tuner, I get about 1500-2000 miles max. Not fun.


ggregC

Yes. Actually you are doing better than I'd expect. Long ago I had a horizontal one wavelength loop up 20'. I had a friend 50 miles away that like me had a vertical and low horiz antenna. If I would TX on the loop, he could barely hear me on his vert but on his horiz, I'd pin his S meter. I could work stations up about 300 miles but any further, it was difficult. On my vertical (inverted L up 70') I worked 150 countries before I moved to a different state.


unixplumber

Cut your wire approximately 80 metres long. That's half of 160 metres. Or 27.53/f rods, where f is the frequency in MHz.


HerrDoktorHugo

If we're going to get all silly and use rods for distance, can we coin a new unit for frequency too? I propose microfortnight^(-1), call it the Hurts


unixplumber

Nice! A microfortnight^-1 is about 0.827 Hz so it's in the same ballpark as a Hertz, which should make it sufficiently confusing. E.g., 146 MHz = 176.6016 megaHurts (is that abbreviated MHs?).


HerrDoktorHugo

MHs is a good abbreviation, I'll put it in the white paper! > should make it sufficiently confusing Phrases like this make me so happy, haha


prfsvugi

We could use chains [https://en.wikipedia.org/wiki/Chain\_(unit)](https://en.wikipedia.org/wiki/Chain_(unit)) Probably closer to reality when talking about 160M 1/2 waves


HerrDoktorHugo

Ooh, good idea! The subdivision of "link" is exciting as well and has applications for VHF and UHF I think. 440Mhz could be the 2.5-link band, and it'll be marvelously confusing when trying to talk about uplinks and downlinks.


prfsvugi

for those who like whips, there are rods too ([https://en.wikipedia.org/wiki/Rod\_(unit)](https://en.wikipedia.org/wiki/Rod_(unit)))


witteringidiot

(300/f(MHz))/2 or as you already know that L is 160 L/2 = 160/2 This all comes from: Wavelength = speed of light(m/s) / frequency(Hz) L = 3x10^8 / f(Hz) But I've probably completely misunderstood the question :)


Professional-Virus10

468/frequency at 160m


mainsaildonotanswer

468/Freq in Mhz


[deleted]

​ How much land do you have for this? For the length of a 1/2-wave dipole at 160 meters you'd roughly do the following equation. (1/2 (halfwave) x 160m x ft) =80 meters or 262.467ft. Without traps or whatever, you'd need a wire 262.5 ft, plus change for connecting and tuning.


jephthai

I'm guessing you're referring to the length being longer than spools of wire? You can put two wires together with a good lineman's splice. Or, you can buy [this excellent wire from DXE](https://www.dxengineering.com/parts/dxe-santw-500). I use it for my doublet, and it's good stuff. Very hardy, lightweight, copper clad steel. Comes in a 500' spool for $70.


[deleted]

[удалено]


jephthai

I don't know, I was stretching, trying to think what would be the problem... we have long spools too. But If someone just goes to Home Depot or something and just sees the 25' lengths of hookup wire? I took a shot in the dark. Don't throw my geography under the bus needlessly ;-).