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I am planning to move into a new apartment, and of course would like to install a HF antenna there, on the roof if possible.

Today I noticed a small Yagi antenna on the roof of the building , more than likely for VHF, but more interesting, seems to be some massive long wire antenna coming from the roof which spans across multiple buildings as shown in the photos below.

Closer inspection, it looks like ladder line of some sort. Would anyone know what exactly this is? I have a feeling that I may be unlucky and already there is a HF HAM operator living the building.

However this "wire antenna if it is" spans across multiple apartment buildings, so i'm not really sure what i'm looking at here:) Thanks in advance.

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  • $\begingroup$ Not sure where you are, but in some countries, you can look up ham licenses by address. Might be a starting point/further confirmation for you to see if someone with a license lives in either of these buildings. $\endgroup$ Oct 15 at 1:46
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It looks like a fibre or telephone cable strung between buildings.

It sets a good precedent for setting up your antenna though - if you can get access to the other rooftop at night, and a catapault or fishing rod. Make it fairly official-looking, with some large bolts and a labels with bar codes and lots of numbers.

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    $\begingroup$ Love your reply:) Thanks. I'll keep that in mind)). Regarding the beam antenna in the first photo, more than likely from a Ham? The worrying is that i'm planning to install a Hex beam on that roof. $\endgroup$ Oct 14 at 17:53
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    $\begingroup$ @Engineer999 Perhaps a 2m or 6m Yagi? The five elements could be a counterpoise for the vertical just above it. $\endgroup$
    – Mike Waters
    Oct 14 at 21:21
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The cable strung between the two buildings has two parts, a strong wire probably made of stainless steel or similar, then you can see some form of cable, as Tommexus said it's probably fibre or telephone cable, or maybe coax, hanging from the wire with lots of evenly spaced cable supports.

The steel wire is used to provide a strong support between the buildings and acts as a strain relief so that the cable or coax isn't supporting it's own weight by itself, which protects the cable or coax from being stretching or damaged, especially at the ends.

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The pictures look a lot like post-socialist country big city residental area. It may as well not be, YMMV.

The Yagi looks like an abandoned old analog TV antenna. Most ham installations use vertical polarization in UHF and this one looks pretty much horizontal.

The cable between the buildings is not an antenna at any rate. This is a communincations cabe of some sort. It may or may not be related to the cell tower at the roof of the building on the right on the last photo.

No sane antenna can work together with a weight-bearing wire.

Some 30 to 10 years ago this is how we got cable TV (75 ohm coaxial) and internet connection (FTP or SFTP). Just before the local authorities got enough power to irrevocably ban the cables hanging between the residental buildings, cable TV / internet providers started experimenting with optical connections that were much safer in regard to static and lightnings. Here and there these wires still hang because there is no one willing to deal with them.

In small communities this is how internet and cable TV work even today.

In general, the picture looks like no one will vigorously object an HF wire antenna. Or two. Luckily, it is 2021 and you won't break anyone's TV set.

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  • $\begingroup$ That yagi looks a lot like for a VHF TV on channel 1 or 2. Though 5 element yagi at these frequencies is a bit on the edge and was used mostly for remote (i. e. cross border) reception. Though communal TV might have used it even for strong local signals, to get better directionality. We might indulge in some dx tv archaeology if you tell is the location and direction of the antenna :-) $\endgroup$ Oct 16 at 8:31
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The ladder line looks like a cable, as several people pointed out already.

As for the Yagi, it does look like a TV antenna, but there's a simple way to tell if it's currently used for ham radio or not: Does it move?

A TV antenna is stationary. It points towards in a particular direction towards a particular transmitter.

A ham radio VHF antenna is typically used in multiple directions. If you come back and see it's been turned, that's a pretty good sign there's a ham about!

"But what if it's used by someone who always connects to the same repeater?" you might ask. A good question but, at least in my parts of Europe, repeaters normally use vertical polarisation. For simplex traffic on SSB or CW over hundreds (or thousands) of kilometers, however, most VHF antennas are horizontal. (So, at least in this part of the world, @fraxinus assertion about polarisation is not that simple to make.)

It's of course possible that it's a ham radio antenna not currently in use. If so, it will not expose itself by moving. If you get axcess to the roof however, or a close by roof higher up, you could easily check if it has a rotor or if it's mounted statically. This will give you your answer.

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