Large Ukraine Portable Antenna Systems? - Page 1
Forum section: electronics / general

author: geo_leeman
author_rank: Regular Contributor
timestamp: March 06, 2014, 02:56:50 am
content: While watching the crisis in Ukraine on CNN this morning I couldn't help but notice these GAINT portable antenna arrays in the back. Does anyone have any insight on these? They seem like some kind of radar system possibly, but there are so many in close proximity in this photo.

author: Wytnucls
author_rank: Super Contributor
timestamp: March 06, 2014, 03:31:59 am
content: There is a rotating antenna, which is the omnidirectional target direction finder array and some scanning vertically, to detect the altitude of the target.

author: Br0ski
author_rank: Contributor
timestamp: March 06, 2014, 05:15:34 am
content: radar for air targets probably only rotate 90 or 180 so they need multiple unitsthe one to the right rotates 360 independent or the one on the top 360 deg coverage better distance that one than the taller ones

author: Frost
author_rank: Regular Contributor
timestamp: March 06, 2014, 08:23:01 am
content: Quote from: geo_leeman on March 06, 2014, 02:56:50 amMaybe they belong to a older surface-to-air missile system like the S-300

author: ivaylo
author_rank: Frequent Contributor
timestamp: March 06, 2014, 08:46:12 am
content: QuoteIt doesn't rotate. It shakes up and down. Look at the thing on the left hereIt is for accurate altitude measurements I believe. The old (80s) Russian military radar complexes used to have a bunch of rotating ones and at least one of these.

author: Richard Head
author_rank: Frequent Contributor
timestamp: March 06, 2014, 09:30:57 am
content: They are primary (as apposed to secondary) radar antennas.The funny looking vertical parabola is called a height finder.It has very high vertical resolution but terrible azimuth resolution.The other (last picture) antenna is a horizontally mounted parabola that has excellent azimuth resolution (but terrible up-down res).The two work in combination to determine with great accuracy the direction of an aircraft.Dick

author: ales22
author_rank: Contributor
timestamp: March 06, 2014, 09:33:35 am
content: @ivaylo In the picture is Tesla RP-4G or RP-5G made in Czechoslovakia. But you're right, We were part of Soviet union from '48 to '89, so it was deployed in Soviet countries. One should be in Kiev, National Aviation University:http://www.czradary.cz/rp4g16.htmland here are some technical detailshttp://www.czradary.cz/radrp4g.html(unfortunately in Czech only) "Presny pristavaci radiolokator" means Precision Approach Radar.

author: daqq
author_rank: Super Contributor
timestamp: March 06, 2014, 09:47:19 am
content: QuoteMinor correction: We were part of the Eastern Bloc, not the Soviet union.

author: ales22
author_rank: Contributor
timestamp: March 06, 2014, 10:14:24 am
content: Yes, you're right. I wanted to make it simple, maybe too much.

author: uwezi
author_rank: Unknown
timestamp: March 06, 2014, 10:27:03 am
content: Quote from: geo_leeman on March 06, 2014, 02:56:50 amThe two radars with elongated vertical dishes are - as was already explained - height finder radars, NATO nick nameOdd Pair(because of the double antenna, a big one and a small one), original name PRV-13. Normally it is linked to a surface-air missile system.http://en.wikipedia.org/wiki/SA-5_GammonThe double antenna to the right is a air surveillance radar, most likely a NATO nicknameBar Lock, original name P-35.http://en.wikipedia.org/wiki/P-35_radarI used to serve in the German navy in signal intelligence 1989-91... These radars were placed everywhere along the Baltic coast of Eastern Germany, Poland, Russia, Lithuania, Latvia and Estonia. We used to listen to and analyze the signals sent out by these radars. It is interesting now to see the actual antennas in such nice pictures

author: geo_leeman
author_rank: Regular Contributor
timestamp: March 06, 2014, 01:25:52 pm
content: QuoteWow! Lots of information! Is it possible that some of these are even the olderP-30system? The P-35 says that:QuoteApparently the V-beam system used a dish fixed at 25 degrees and from the difference in range provided by the horizontal antenna and the tilted antenna an approximate altitude was obtained. Sounds like an excellent simple vector refresher problem for students!Either way, these are pretty old and incredibly powerful. 1MW systems from either 1955 or 1958 on the E/F band.

author: uwezi
author_rank: Unknown
timestamp: March 06, 2014, 03:26:03 pm
content: Quote from: geo_leeman on March 06, 2014, 01:25:52 pmAt the time I was pretty amazed by how 3D information was acquired in old style systems, as much as I was amazed by more modern (talking late 1980s) technology using phase-array antennas.As far as I can remember we have not encountered any P-30 or "Big Mesh" anymore in the Baltic 25 years ago...Also the upper of the two antennas in P-30 is actually tilted by 25 degrees:http://www.radartutorial.eu/19.kartei/karte921.en.htmlHowever, these might be ideas which could be used in small-scale microcontroller projects using ultrasonic range finders...

author: geo_leeman
author_rank: Regular Contributor
timestamp: March 06, 2014, 03:37:02 pm
content: QuoteHmm.. I didn't notice that. So that is a scanning of two beams and location by a direct 3D solver?QuoteTrue. Assuming the target size is small compared to the range such that the geometry doesn't kill the location. Maybe even just some simulated data and asking students to solve it geometrically. This is all pretty advanced for it's day though!

author: uwezi
author_rank: Unknown
timestamp: March 06, 2014, 03:52:57 pm
content: Quote from: geo_leeman on March 06, 2014, 03:37:02 pmA truncated oval antenna like the ones you can see on all these pictures generates a radar beam which is a narrow stripe perpendicular to the long axis of the oval. This means that the horizontal antenna of the P-30 creates a vertical radar beam, while the tilted antenna generates a beam stripe which is tilted 25 degrees off the vertical axis.Now both antennas are mounted on the same motor axis and rotate. At ground level both the vertical and tilted beam are parallel and any reflection from a target at ground level will show up at the same time for both antennas (which are working on different frequencies or sending out pulses with a time delay). But a target which appears at a higher elevation angle from the radar site, the tilted antenna will see it when the horizontal antenna is already pointing in a different direction - the higher the elevation, the further the upper antenna has to be rotated to "see" this target.From the time it takes for the echos to return to the antennas you get the distance to the target and then it is just pure trigonometry to also determine the height of the object above ground.The newer systems with two horizontal antennas are working simultaneously on several different frequencies or using a frequency sweep together with an antenna system which directs the different frequencies into different elevation angles. From the echos at the different frequencies the system then determines the elevation angle and from the time delay the distance.

author: ivaylo
author_rank: Frequent Contributor
timestamp: March 06, 2014, 04:36:10 pm
content: QuoteLove these enemy equipment nick names. It's funny the technicians working on them had their own nick names for them. The PRV-13 they called "Elephant" because when on, it looked like a giant elephant shaking its head up and down (can't find a video of it but the movement does look ridiculous, it's pretty rapid and quiet at the same time (exemplary mechanical engineering I guess, shaking all that mass on a mobile platform in a storm for example doesn't look trivial to me)). The P-30 they called "Christ". Now I realize it must have been a paraphrase on the local language of P-30 "Khrustal" (Russian: "??"; English: crystal). Pure blasphemy...

author: geo_leeman
author_rank: Regular Contributor
timestamp: March 06, 2014, 04:42:57 pm
content: QuoteI see! Thank you. The link you posted earlier also has a link to a V-beam graphic.http://www.radartutorial.eu/06.antennas/an65.en.html

author: Wytnucls
author_rank: Super Contributor
timestamp: March 06, 2014, 04:59:00 pm
content: They can be seen in movement here:http://footage.shutterstock.com/clip-2673458-stock-footage-russian-radar-system-in-work.html?src=rel/5465027:9/gg

author: geo_leeman
author_rank: Regular Contributor
timestamp: March 06, 2014, 05:03:47 pm
content: Quote from: Wytnucls on March 06, 2014, 04:59:00 pmThat setup has a little bit of momentum! The pedestal mounts have a lot of un-even loading unless that equipment in the vans is weighted at the back.I remember being up inside a WDR-88D weather radar a few years ago and marveling at how well it was balanced. Just a small motor (or 3 fingers on your hand) was enough to rotate the dish.

author: uwezi
author_rank: Unknown
timestamp: March 06, 2014, 05:49:53 pm
content: Quote from: geo_leeman on March 06, 2014, 05:03:47 pmI guess that's one of the reasons why these big antennas only have a reflector consisting of a wire mesh. Otherwise it must be impossible to rotate them on a windy day.Modern phase-array antennas don't rotate at all, instead you have four panels pointing into different directions. The beam deflection is by means of shifting the phase of the RF signal between neighboring antenna elements...

author: uwezi
author_rank: Unknown
timestamp: March 06, 2014, 05:52:08 pm
content: Quote from: geo_leeman on March 06, 2014, 05:03:47 pmone of these?

author: daqq
author_rank: Super Contributor
timestamp: March 06, 2014, 05:53:02 pm
content: If you're into big radars:http://englishrussia.com/2013/08/01/date-with-lena-m/Search the site for 'radar' for more.

author: uwezi
author_rank: Unknown
timestamp: March 06, 2014, 06:43:46 pm
content: Quote from: geo_leeman on March 06, 2014, 04:42:57 pmAnother Eastern block V-beam radar is the ship-borne NATO nicknamedHead Net C. Here the tilted and vertical antennas are mounted rear-to-rear, which means that the height information is lagging 1/2 rotation behind.

author: geo_leeman
author_rank: Regular Contributor
timestamp: March 06, 2014, 08:07:48 pm
content: Quote from: uwezi on March 06, 2014, 05:52:08 pmOne of those! This particular one was a dual-pol prototype back in 2009. It was then struck by lightning and down for awhile. The mechanics were just beautifully engineered. I remember them doing analysis of smoke plumes from wild fires with this in the off (non-severe storm) season.

author: geo_leeman
author_rank: Regular Contributor
timestamp: March 06, 2014, 08:10:23 pm
content: Well, as long as things are moving slowly (as they were then) I guess that wasn't a huge problem. It looks like these scanned at about 7 RPM max, so < 5 seconds lag isn't too bad.Quote from: uwezi on March 06, 2014, 06:43:46 pm