On 24/11/18 21:29, Sergio Manzi wrote:
Hello Warin,
I'm afraid we're opening a can of worms here, but you're right:
something needs to be fixed, and here below I'm trying to contribute
with some considerations...
Thanks... rather than 'fixed', guided might be a better term. 'Type'
just provides for too much freedom in the responses.
The Wiki [1
<https://wiki.openstreetmap.org/wiki/Tag:man_made%3Dantenna>] gives a
very good definition of what an antenna is: an "/interface between
radio waves and electrical signals in a transmission line/".
Well it is a better attempt. But needs improvement (I can say that as I
wrote it :) ) "/interface between radio waves *in free space *and
electrical signals in a transmission line/".
Consider a wave guide - the field there could be described by some as a
radio wave .. but not in free space. And of course a wave guide is a
transmission line.
That interface can work in either or both directions:
* *receiving *(/RX, radio waves to electrical signal/), like the TV
antenna on the roof of an house or a radio-telescope.
* *transmitting *(/TX, electrical signal to radio waves/), like the
broadcasting antenna of a commercial TV or the transmitting
antenna of a VOR radio direction navigation system.
* *receiving/transmitting* (RX/TX, /both directions/), like those on
the tower of a mobile telephone cell or a radar.
Not all antennas are *communication antennas*: communication antennas
are for conveying information ("meaning") from one party to another
(/and I would add "in a bidirectional way" or we should call it a
"*broadcasting antenna*", but I'm not totally sure about this latter
specification/). Some other kind of non-communication antenna: the
radio-telescope, the VOR, the radar.
Yep. Though communications can be one way e.g. a TV signal conveys
information, sometimes useful like a weather forecast. But I am
reluctant to put 'communication' down as a value - covers too many things.
For the above I think an *antenna:usage=** tag could be a correct tag,
with values like: communication, broadcasting, radio-telescope,
navigation, radar, measurement, ham_radio (/there is not such a thing
as an "ham radio" antenna type, per se: hams make uses of a lot of
different antenna types/).
As for the "type" of antennas, *there are **a lot*: monopole, dipole,
mast radiator, whip, Yagi, Log-periodic, random wire, loop, quad,
rhombic, helical, beverage, ground plane, collinear, traveling wave,
curtain, horn, dish, etc., etc.
Biconical, biconilog, patch ... heaps of them. Some even describe the
matching .. a 'Roberts Dipole' for example. A 'quad' to me just says 4
.. 4 of what? Helicals, bow ties, dipoles .. A 'phased array' also does
not say what the driving antennas are nor the number of them.
Furthermore there are some inaccuracies in the above (/a "dish"
antenna is actually //a system//built from two components: a
reflector, the dish, and the true antenna located in the focus of the
dish reflector/) and possible complications (/you can have an array of
antennas, like the array of four helical antennas pictured in the wiki
page/).
A 'ground plane' is also a system of at least 2 components. And the feed
to the dish can be in several different locations...
antenna:reflector=dish/ground_plane/* ?
I'm really unsure if it is worth to specify antenna types. Beside, I
think most mappers will be unable to correctly identify antenna types.
Unfortunately some mappers want to put these things down .. so provision
for that has to be made to avoid confusion.
Someone has also included polarisation in the types value .. so that
needs to be addressed too,
antenna:polarisation=vertical/horizontal/circular/circular_clockwise/circular_anticlockwise
should do.
A radom_*e*_ *is not an antenna*, but the weatherproof enclosure that
protect an antenna.
Sigh. Yep. But that is what mappers see and want to put down. Don't know
what to do with it yet. Similar to the dish problem, they see the dish
and want to put that down without going into the feed detail or the true
antenna. Some of the dishes are covered too so it will not be easy to
have mappers detail more than 'dish'.
antenna:enclosure=radome/* ?
Some microwave repeater antennas get covers - usually for snow conditions.
In the wiki there is a lot of talking (/and some proposed tags/) about
"transponders", but the term is used in an absolutely inaccurate and
wrong meaning: a transponder is "/is a device that, upon receiving a
signal, emits /_/a different signal in response/_" [2
<https://en.wikipedia.org/wiki/Transponder>]. What in the wiki is
called a transponder can probably be more accurately described as a
"repeater" [3 <https://en.wikipedia.org/wiki/Repeater>]. Unhappily
man_made=communications_transponder is already in use for absolutely
wrong features, as in [4
<https://www.openstreetmap.org/node/2199511457#map=19/44.98542/9.01678>]
where it it is used to tag a cell tower.
Yep. Non experts tagging things as well as they know how.
Enough, for now, but of course I'm open to the discussion and I'm
ready to contribute for what I can (/I'm not an expert in the field
but/ /I am a former radio amateur and a former telephone company's CTO/).
Cheers!
Sergio
[1] https://wiki.openstreetmap.org/wiki/Tag:man_made%3Dantenna
[2] https://en.wikipedia.org/wiki/Transponder
[3] https://en.wikipedia.org/wiki/Repeater
[4] https://www.openstreetmap.org/node/2199511457#map=19/44.98542/9.01678
On 2018-11-24 02:47, Warin wrote:
Hi,
I was looking at the wiki for antennas
https://wiki.openstreetmap.org/wiki/Tag:man_made%3Dantenna
I made some additions to the definition and added some photos etc.
It is still rather sparse. I'd like to be able to further define what
the antenna is.
Unfortunately on the German wiki there is the use of antenna:type ..
with a confusing set of values.
(eg communication, special, parabolic_satellit,
parabolic_satellit_uplink, radar)
These appear to be the use of the antenna.
Perhaps this could be antenna:use=radio/TV/radar/wifi/cell_phone
I don't think 'communication' is a good tag - any antenna performs
the function of communication.
Similar for satellite (note last 'e' for British English), that might
be all you can tell from the configuration and direction of the
antenna but does not define its use.
Then the 'type' of antenna .. better described as antenna:configuration ?
Values could be monopole, dipole, yagi, dish ... yes dish will have
sub tags for the feed system etc.
Broad thoughts?
Not after detail at this stage but antenna:type to others such as;
antenna:use?
antenna:configuration?
antenna:mode=tx/rx/2way for the direction of communication?
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