The antenna behaves differently in various environments (height, surrounding buildings, substrate), sometimes the changes are very pronounced. The variant with a balun like FD-4 is proven. Not every band will be ideal, but even the worst case will be decent.

See: http://www.radio-foto.net/radio/windom.php

The balun must be made well - using suitable materials, appropriate wire, and securely protected against moisture ingress.

Suitable antennas are offered by Jirka. http://www.ok5im.com/

The G5RV antenna has 300 ohms at the feed point, so you can use a 300 ohm twin line. But you still have to transform the impedance with a balun to 50 ohms. Whether you do it at the feed point or at the transceiver is up to you, and this applies to all bands on which the antenna operates!!!

The G5RV is not a bad antenna. However, Luis originally designed it as a gain antenna for the 20m band, and it was later discovered that it can be used on other bands.

The version with the ladder to the shack is better.

The impedance of the antenna is strongly dependent on the environment, and there is very little hope that the impedance matching will work on all bands. Moreover, connecting a balanced and unbalanced feed line will cause the flow of return currents and likely problems with TVI.

Which antenna depends primarily on spatial possibilities and requirements for the type of connection. For example, 1/4 vertical on 80m is an excellent DX antenna, but for close range connections, a horizontal dipole or Inv.V is better.

Lukáš, could you specify the requirements for the antenna and the spatial possibilities in more detail?

The required bandwidth on 80m would only be achieved by a dipole antenna with a large conductor diameter (several meters). Usually, this is realized by flat or even better spatial placement of multiple conductors. For example:
http://pagesperso-orange.fr/f5rrs/images/ya-30.jpg

A Windom powered with a ladder line can be tuned anywhere – if there is a suitable ATU.

The G5RV construction with a ladder line to coax will not be good. For a narrow segment, e.g., only CW, where the higher frequencies are multiples of the lower band, it might be possible to tune it, but I wouldn't attempt it for larger tuning.

W3DZZ is operational, but the bandwidth on 80m is smaller. If quality traps are made, it works well.

There is also the option of parallel dipoles, e.g.:
http://www.hamuniverse.com/multidipole.html

I would choose either FD-4, because it is a simple antenna, proven over the years to be a good antenna, it results in a short feed with coax cable, but with the disadvantage that the bandwidth will be smaller, or a Windom powered with a ladder line, which requires a bit more effort (ladder line, ATU, and tuning when changing frequency), but rewards with the ability to tune anywhere.

Hi,

It will be my pleasure if the advice is helpful. Hopefully, I will get a QSO with you, hi. A toroid for the balun for FD-4 can be obtained from Martin Karasz, or a balun or the whole antenna from Jirka OK5IM. A suitable toroid is rarely just lying around... and poor material would negatively affect the properties of the antenna.

Z-match is an excellent matching circuit. Feeding with a ladder line is a bit problematic since it needs to be made very well due to the bend (from the center of the antenna down, then to the side and up to the shack). In the case of a shack on a lower floor, it would be simple.

The actual decision about the antenna is usually made by a radio amateur based on feeling. For example, I have bad experience with HB9CV and I prefer antennas with higher impedance, ideally with 50 ohm impedance at the feed point (1/4 vertical, OWA yagi, quad). But there are certainly radio amateurs who have the opposite experience.

Hello Lukas,
I see you are an apartment ham (like me), so I dealt with the same concerns and I am still dealing with them…
I would also recommend FD4, best with a balun, it will tune beautifully everywhere, but it will be good with a balun too. Buy a ready-made balun because trying to figure out which toroid will be good doesn't seem very practical to me.
Imagine putting your new FD4 up and down maybe 5 times and changing the balun for the great 'interest' of neighbors and residents of nearby apartments – you will create a lot of problems because every internet outage, TV, and broken television at the neighbor's will fall on your head. I speak from my own experience! One more piece of advice – build antennas in the housing estate fundamentally (I'm not joking) at night and when it is deserted. In the morning they won't even notice the wire.
Check out my pages for inspiration http://www.QSL.net/om3cug where you will see how I have made wire antennas for 80/160m and mainly how I have built the vertical HF9V on the roof and anchored without problems. FD4 will work well from 80 to 10m but when you set up a vertical on the roof, your eyes will first pop out and then your jaw will drop because you realize what a huge difference it is on the upper bands compared to wire. I only operate with QRP 5W and look at my pages yourself to see what can be done with such an antenna setup.
I wish you good luck with the antenna installation, 73 Igor OM3CUG