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Feeding a resonant dipole with ladder line

Yes, I’m using Firefox and can’t see the cursor.

I had it a lot and it went after a Firefox update. It was on both Windows and Linux Firefox versions. Firefox 69.xxx on Windows and Firefox 68.xxxx on Linux no longer show this invisible cursor problem.

Also you can try flushing the cache for the browser but I’m sure it was a Firefox update that fixed it for me.

My Firefox see the cursor. Windows 7.

73 Phil

My OS is Windows XP Professional and I see the cursor OK on programs like Word or Power-Point, it’s just here, when writing a post on the SOTA Reflector that I don’t see the cursor anymore. This has been happening for about 1 month or so.
I don’t know yet how but I’ll try to do what Andy suggests of flushing the cache for the browser.
Hey, while I’m still typing this post, I saw the cursor back visible again but the joy just lasted very shortly, as it’s now become invisible again. :frowning:
73,

I see you’ve chosen the endfed route, but i was going to say don’t get too “hung up” on removing sag from a dipole - for any span having finite weight, zero sag requires infinite tension.

As a side thought, could I attach multiple elements to the matching transformer/balun like a fan dipole? I know it works with a centre fed dipole, but I’m not sure if this would work with an end fed antenna?

The original plan was to set this up for 20m band at about 10 meters above the ground.

It occurs to me that (if the support poles at each end were spaced far enough apart) this would also make a fairly decent NVIS setup on either 40m or 80m.

I’m wondering if I can put 2 elements up & end up with what one might describe as an “fan end-fed half-wave” (if there is such a thing)?

It should work. It will be a bit tricky to adjust on multiple bands, as a fan dipole is, but I believe it should work, although I have never tried that, only the fan dipoles with a common balun at the center and it worked fine.
73,

Guru

Thanks Guru. Could be an interesting experiment.

When I go away on holiday in the caraven, I run a vertical mast with two elements on a 1:1 balun effectively giving me a “fan vertical” with a 1/4 wave on both 40m & 20m. This works well.

I just wasn’t sure if the high impedance and different matching arrangement at the end would make a difference.

As you said, might be a bit of a pain to get it tuned, but it’s going to be a fairly permanent install, so I only need to do it once!

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I think that what makes the usual fan dipole work is that on the band where there is a resonant dipole, its impedance is low but all the other dipoles present a high impedance on that band. So the resonant antenna gets almost all the power and the other wires are almost invisible. However with parallel high impedance antennas more than one wire will receive power on some bands. This may not matter. The atu would possibly have two high impedance antennas in parallel, the resultant impedance would be a bit lower (say half) than it would be with a single resonant half wave or full wave. But then, as a 40m half wave works as a full wave on 20m there seems to be no reason to add more wires.
Andrew VK1DA/VK2UH

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I made my 40m halfwave a bit long and was able to get a less than 1.7 to 1 SWR on 40, 20, 15 and 10 meters.

I had wondered if I could set up a 40m & use it as a full wave on 20m.

Also considered setting up an 80m full wave, giving a half wave on 40m for an NVIS antenna, then setting up something else for DX on 20m.

Nice to know, thanks.

No, “fan” EFHW’s don’t seem to work. No, I don’t know why, but my experience has been replicated by quite a few others over on the “End Fed Half Waves” Facebook group. I wanted to place a 30 mtr half wave element in parallel with a 40 mtr one, since a 40 mtr EFHW, as pointed out elsewhere in this thread “should” already work for 40, 20. 15 & 10. Nothing bad happened to the resonances that worked before addition of 30 mtrs, but the antenna just did not seem to know that 30 was there. VK4TJ.

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Thanks. I think Andrew (VK1DA ) makes a good point that explains why this wouldn’t work:-

Thanks again for all of the replies & pointers folks.

Hi John

I have to admit to not liking end fed high impedance antennas. But my arm gets twisted occasionally and I do use them.

I suggest it would be worth evaluating the 30m EFHW on its own, if you didn’t already do that. Having a say, 2000 ohm impedance in parallel with a very reactive 5000 ohm impedance of the 40m EFHW should allow the 30m antenna to operate as if the 40m wire wasn’t there, almost, provided the matching network covers the 30m band. A tuned matching network would need retuning for 10.1 MHz. Curious to know whether you tried the 30m antenna independently using the same matching network.

In my early years of ham radio I used a transmitter built by my older brother with a pair of 807s etc. the microphone case was metallic and if there was any RF on the chassis when using end fed antennas, you got RF stings and zaps off the mike. This formed my Pavlovian training to avoid such antennas. :wink:

73 Andrew VK1DA/VK2UH

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