I stand correcred.

Quote from: Hydra009 on January 10, 2023, 06:47:04 PMI stand correcred.

You're a stand-up guy! Not many people will admit to an error on the internet. I've made many. Hail, fellow well-met!

I understand The Patriot system RADAR tracks both the target and the missile and sends it intercept data to augment the onboard systems. Crazy complicated. As a weather RADAR engineer, we were always getting jammed by false returns and implementing fixes. Even a picket fence could look like a doppler weather return. I bet those missile RADAR systems have sophisticated methods to evade jamming and countermeasures.

Quote from: Hydra009 on January 10, 2023, 06:47:04 PMI stand correcred.

Sorry. I didn't mean to sound like an asshole. My comment was supposed to be tongue in cheek.

I spent a few days at Sill back around 2010 or so trying to figure out what was wrong with the sensors on a new small arms range they were having built. They were doing a lot of live firing of both conventional artillery and MLRS (possibly HIMARS). The conventional artillery was impacting surprisingly close to us. 1 to 2 seconds between impact and boom. The MLRS was firing from slightly further away 2-3 seconds from launch to the sound getting to us. I'm not sure where it was coming down. I was really surprised how close we were to the impact zone in particular. In any case everything was really loud. Very impressive. The people living in Lawton probably hate it... 

You're fine.  I was thinking in terms of infrantry housing/training, I didn't know it was inadequate for missile defence testing.

Poland to send Leopard tanks to Ukraine

Mmmm...those will pair so well with the Marders and Bradleys.  And AMX-10 for fire support / recon.  All backed up by Krabs and CAESAR and HIMARS!  What a team!

Russia lost another 500 soldiers and 10 tanks yesterday

Quote from: Cassia on January 10, 2023, 09:54:42 PMI understand The Patriot system RADAR tracks both the target and the missile and sends it intercept data to augment the onboard systems. Crazy complicated. As a weather RADAR engineer, we were always getting jammed by false returns and implementing fixes. Even a picket fence could look like a doppler weather return. I bet those missile RADAR systems have sophisticated methods to evade jamming and countermeasures.

First a bit of history. I completed my Nike Hercules Training in 1980. Nike was already being phased out at that time so I was offered the chance to go straight from Nike training in Patriot training. I declined because 1) I had just finished 60 straight weeks of training and was ready to go to work. 2) As a junior enlisted soldier I was unlikely to get to work on a Patriot system any time soon. Operations and maintenance would mostly be performed by E-6 or E-7 so I would probably be spending most of my time standing inspections and marching in parades. 3) There were not enough Patriot systems available yet to train everyone so even the E6's and E-7's in the training battalions were spending most of their time standing inspections and marching in parades. My knowledge of Patriot is very limited.

Nike systems were based on technology from the 40's-60's so it is old. Older than I am and 100% analog. The computer that plotted intercepts and generated guidance data for the missile used tube driven op amps to add or subtract variables, determine rate of change, and divide a variable by a constant. It used mechanical motor driven potentiometers to multiply or divide a variable by a variable or store a variable for a long time. By the end of 83 I had moved from Nike to a SATCOM MOS so it has been almost 40 years since I worked on a RADAR period. I don't remember a lot about what I knew then but here is a snippet.

Nike batteries used 4 to 5 RADARS. All batteries had at least 4 RADARS. The Low Power Acquisition RADAR (LOPAR), the Target Tracking RADAR (TTR), the Target Ranging RADAR (TRR), and the Missile Tracking RADAR (MTR). Some batteries were also equipped with a second acquisition RADAR the High Power Acquisition RADAR (HIPAR). The HIPAR was a later edition to the system and was very similar to the RADAR used in early AWACS planes.

I am sure I am missing something, but from what I remember our main tools for Electronic Counter Counter Measures (ECCM) were Dickie-Fix receivers, manually changing frequencies, and the HIPAR had an automatic frequency hopping mode. Dickie-Fix receivers basically work by comparing incoming signals to a know reference and canceling signals that don't match. Changing frequencies is just that. Moving from a frequency that is being jammed to one that isn't being jammed.

Ground clutter was dealt with on the display side of the system with a system that works a lot like noise cancelling headphones. The incoming signal is split. One part is inverted 180 degrees then sent through a delay circuit that would delay it one pulse repetition. The signals were then combined again and anything that had not moved since the last signal would cancel itself out.

Dictator's cook humiliated after bragging about victory

Mr Prigozhin's quasi-military group of convicts posted a photo allegedly from Soledar's salt mines and typed that they had captured all of Soledar.

Not only have they not captured all of Soledar, the picture isn't even from Soledar, as the Russian military rightfully pointed out.  Russia's military might not have the best equipment or armor or air defense or medicine or food or even a pot to piss in, but they do have their wits about them - especially when they surrender.

QuoteRussia's Defense Ministry shot down Prigozhin's boast that his own men had single-handedly brought Putin a win, instead confirming Ukraine's announcement that fighting was still underway in the town.

Moreover, defense officials suggested Russian airborne units and assault teams are leading the charge. The Defense Ministry made no mention of Wagner whatsoever.

The rebuff comes as praise for Prigozhin's outfit hit a fever pitch among pro-Kremlin figures, and the notorious mercenary group threatened to outshine Putin's regular soldiers on the battlefield.

QuoteDespite Prigozhin butting heads with top defense officials and government officials, the Kremlin has largely allowed him to do as he pleases—but they seem to have fired their first warning shot this week in a sign of things to come.

Putin's appointment on Tuesday of a controversial colonel-general as the new ground forces chief was done "as a snub to Prigozhin," a source close to Russia's General Staff told the outlet iStories.

Quote from: PopeyesPappy on January 11, 2023, 01:01:30 PMI am sure I am missing something, but from what I remember our main tools for Electronic Counter Counter Measures (ECCM) were Dickie-Fix receivers, manually changing frequencies, and the HIPAR had an automatic frequency hopping mode. Dickie-Fix receivers basically work by comparing incoming signals to a know reference and canceling signals that don't match. Changing frequencies is just that. Moving from a frequency that is being jammed to one that isn't being jammed.

Ground clutter was dealt with on the display side of the system with a system that works a lot like noise cancelling headphones. The incoming signal is split. One part is inverted 180 degrees then sent through a delay circuit that would delay it one pulse repetition. The signals were then combined again and anything that had not moved since the last signal would cancel itself out.

Frequency hopping you say? Thanks Hedy Lamarr !


https://science.howstuffworks.com/innovation/famous-inventors/hedy-lamarr.htm

Quote from: Cassia on January 11, 2023, 10:20:34 PMFrequency hopping you say? Thanks Hedy Lamarr !

I knew about Hedy. Unfortunately for her no one used the tech she thought of first until after her patents had expired so she never made any money from it.

Starting in the 60s super duper secret squirrel comms systems were using spread spectrum for both ECCM and to keep signals hidden. 802.11 and CDMA both use spread spectrum techniques so today it is literally everywhere. 

Quote from: PopeyesPappy on January 12, 2023, 07:51:28 AMI knew about Hedy. Unfortunately for her no one used the tech she thought of first until after her patents had expired so she never made any money from it.

Starting in the 60s super duper secret squirrel comms systems were using spread spectrum for both ECCM and to keep signals hidden. 802.11 and CDMA both use spread spectrum techniques so today it is literally everywhere. 

I designed a microprocessor card for a commercial aviation transponder. I believe miliary RADARs have "ID Friend or Foe" equipment that interrogates transponders. They use a transmitted random delay between interrogations and the reply to sync-up and avoid being faked out by the bad guys. It's like an electronic "Spy vs Spy" going on all the time. I have read horror stories about the reliability and design of Russian IFF equipment. Makes sense in light of this war.

Russia sure loves to repeat mistakes - stepping on the same rake twice, as the Ukrainians say.

They massed troops at Solenar and sure enough, a Ukrainian rocket wiped them out - killing over 100 in a single strike.

(There's a marked increase in copium in the twitter comments - pathological skepticism/denialism, the automatic assumption that because it's coming from a Ukrainian source that it didn't happen or the numbers are severely inflated, one comment even promotes the false russian claim of wiping out 600 Ukrainians in a "revenge strike" that was independently confirmed to have hit near an abandoned building, etc.

It appears that emerald mine guy's lack of policing Twitter, undoing attempts to keep Twitter from becoming a safe haven for trolls/extremists, is bearing fruit)

While I'm on the subject of news trustworthiness, I'll just tell you guys that I personally try to give you guys timely and objectively true information (though obviously I editorialize - I have a pretty clear position which I don't try to hide)

Ukraine has a pretty clear position as well, and although details get kinda murky in war and there's a lot of guesswork involved, there isn't evidence of outright deception or inflated numbers from official Ukrainian sources.  When they say they captured Izyum, they actually captured Izyum.  When they say they took Kherson, President Zelenskyy was there personally.  When they claimed huge Russian losses (10k at the time), most of the world was unprepared to accept it and preferred the default assumption that numbers are inflated on both sides.  Well, Russia actually leaked a document showing guess what - about 10k combat losses - precisely what Ukraine was claiming.  Various news organizations and Oryx work to independently substantiate Ukrainian claims, and by and large, they do.  You can go down the list, pick a battle or a missile attack or a Bucha-style war crime, and the Ukrainians are shown to be telling the truth.

And it makes sense why the Ukrainians would be highly motivated to tell the truth - they rely heavily on foreign support, so maintaining trust with people halfway around the world is literally a matter of life and death for them.  So they can't risk harming this relationship with falsehoods.

That said, there has been some wild stuff circulating around that isn't true, mostly from 3rd parties.  Ghost of Kyiv, Arma 3 footage purporting to be an airstrike on a Russian convoy, and mistaken reports that the Russian cruiser Admiral Makarov was struck by Ukrainian missiles and was on fire (yours truly made an oopsie in passing along such mistaken reporting before it was corrected)

Meanwhile on the Russian side, which already has a bad history of false reporting, has gone into overdrive.  Russian official death counts have consistently been highly deflated and Ukrainian losses highly inflated.  They claimed to have destroyed more Bayraktars than Ukraine had.  They claimed to have destroyed a bunch of HIMARS (amusingly, even one impossibly perched in the second story of a building) yet the US has yet to claim the loss of even a single HIMARS vehicle.  They have vacillated between denying various massacres ever happened to claiming that they were justified.  They famously claimed that the Moskva was still afloat but damaged - but not through enemy action - before it was sunk by "rough seas" which suspiciously did not exist elsewhere in the Black Sea.  They claimed that all hands were evacuated and safe, but some Russian families raised hell about their missing sons.  Russia claimed that the HIMARS strike that hit Russian troops at Makiivka only killed 63, yet curiously, a lot more than 63 troops were mourned at funerals in Russia.  Russia has put out pixelated video game footage from the 90s purporting to be real footage of a HIMARS, lol. There's a laundry list of lies, damned lies, and statistics.  I could go on and on, but I won't bore everyone.

So when Ukraine says one thing, and Russia says another, I know which one is much, much closer to the truth.