Shooting through walls is cool but could someone PLEASE let me know how it could not work with spells? Its implanted and says it overlays sight which seems way too broken on a caster for my liking.

The "Radar Sensor" is on pp36-37 of Augmentation.

The problem is that it does indeed overlay sight ... electronically. Therefore the mage cannot use it for LOS, as only optical means can be used for that purpose (even if implanted).

Not to reawaken an old argument, but then why can a mage use electronic cybereyes. I always thought the ruling was if one paid for an implant with essence then it was part of the aura and, thus, can be used to target LOS spells.

That's a good question--my thinking is that radar, as an active sensor, is qualitatively different than normal cybereyes functions.

That said, under the generic "if you paid essence for it..." rule, I could see this being allowed. Nasty bit of kit, though.

You're not going to allow casters to use it because it would break the game.

It's bad enough with APDS shotshells.

I always figure that the Cybereyes themselves were optical-based. There has (in the past) been a differentiation between optical and electronic in things like Vision Magnification.

Yeah, as much as it is broken, I'd allow casting through it. With respect to occular drones, I'd allow casting through them, unless it's operating away from the body sending it's singles wirelessly back to its "host."

The ocular drone is specified (errata or FAQ, can't remember which) as being unable to be used for spells while not firmly in the socket.

Eureka! Perhaps the Radar Sensor needs Augmented Reality!

Don't explain it. Just tell your players no.

It does say that it can replace or overlay vision, so it seems that it can be like AR or like low-light. It's up to the GM.

I dont know why everyone is so scared of radar sensor. Sure it gave me a massive.... anyways, it really isn't too powerful.

First requirement for GMs dealing with radar characters is a formal declaration of the structure rating of walls and whatnot. Also, with wireless as it is. When battle breaks out, so does the jamming. And that piddly signal of 2 will be out in no time.

You also have to wonder how the corps would react to this new advancement. Would they be using it too? Would they have sensors specifically designed to pick up that frequency, and thus sound an alarm?

I would have been happy had they left it out entirely, but now that the cat is out of the bag, instead of trying to stick it back in and pretend it doesn't exist, I think we should stick with the rules and deal with the consequences, I do assume they play tested it and found it to be at a reasonable power level.

How about this argument re: mages

Normally, the mage would be able to use the radar sense to cast spells, just like using an eye mod would. The radar emissions themselves would be similar to using a flashlight to assist in spell targeting. However to actually provide useful information, considerable computer processing of the returned radar signals is necessary. It is this image processing that makes the mage normally unable to target spells using the radar sense.

Note that in certain rare cases, the mage can use the ability to see into the radar spectrum to target things, namely anything with an active radar emitter in the same wavelength. (just like you could target a torch or flashlight). So, if you have the radar sense cyberware, a mage with radar vision can blast you by looking at your radar emissions. If you are just using a radar emitting helmet, the mage can just blast the helmet.

[edit]
On blocking the radar waves: in general, anything that blocks wireless signals also stand a pretty good chance of blocking radar.

In addition, plenty of people would carry 'punk busters' that give off a warning when they notice a radar sweep. Note that the range of the punk busters is roughly twice the effective range of the radar sense itself.

In addition, most jammers will degrade the radar sense, with more powerful jammers making it completely useless.
[/edit]

Jamming a wireless signal and jamming radar are not the same thing in real life. By wireless I mean 2.4GHz and 5GHz respectively. Radar can be anywhere from 8-12GHz or even 40GHz. Something that jams a wireless signal would not necessarily jam radar. I am unsure how this works in the rules though. Do jammers still jam radar in SR4 rules?

Radar sense implants generate composite electronic images that are merely representations of what the sensors are recieving back. The sensor data is patched together and translated to a visual representation of the what is there (this can be overlayed over existing vision with AR/image link creating a composite image or normal vision can be switched off and you can use just the radar representation).

Using both radar sense and ultrasound impedes magic use because they create a completely artificial representation of reality generated by the processor from the myriad information recieved by the sensors - though this happens to be accessed through your visual senses for convenience it does not satisfy the LOS prereq of spellcasting targeting (but rather a highly-processed, composite representation of a scene, figure or object entirely computer generated from non-visual data). In the same manner that you cannot target an ARO construct with a spell you cannot target the visual representations produced by radar and ultrasound.

I would say "No" very fast here out of one simple thing.

It is not eyeware.

Eyeware are part of cybereyes and allow for optical vision. Radar Sensor and Ultrasound are separate headware additions that overlays the users sight, very much like adding a transparent membrane over the characters vision.

The mage would be able to SEE things but cannot target it directly because he cannot see or target the aura of the object or person in question.

EDIT:
I wouldn't stop the mage from blasting away the wall right into the face of the target on the other side though.

The easiest way for a corp to detect someone using radar would just be to use Increased Sensitivity microphones throughout the facility. The sensors should be able to "hear" the ping of the radar bouncing off the surfaces.

Sea mammals and military convoys use that tactic so I don't see why it wouldn't work in SR.

RADAR is not SONAR. There is no audidible sound from radar bouncing off surfaces. One uses sound, the other uses radio waves. The only way to detect a radio wave would be to have some sort of RADAR yourself. Anyways, if you had such an increased sensitivity microphone there would have to be some way for it to make a distinction between normal sound and the sound the "bounce" makes. You would get a lot of false positives with such a device. Just simply having a very sensitive microphone is going to do nothing for you.

ahhh...guess that's why I'm in business and not science.

So how do radar detectors work? And why aren't they in SR?

You have one in every radar employing device, since those consist of a radar transmitter sending out a radar cone (like shining a flashlight somewhere) and a receiver that receives the radar waves that get reflected back (like your eyes receiving the reflected by objects you shine your flashlight at). As for why receivers aren't listed separately ? Probably because it is not worth it dropping passive radar cameras all over the place in regard to the amount of armed individuals employing that particular electromagnetic spectrum to raid your base.

The main difference between your run of the mill flashlight and radar"light" is that each gets reflected by different things. For ease of description and gameplay regarding the implanted radar system, I'd just go with it reflecting off of metallic substances (plus anything you deem similar enough) and being absorbed very well by fluids (such as the ones inside your body).

So you could see the cabling in the wall, the weapon the guard (who would appear as a shadow, due to absorbing most of the radiation) behind it is carrying, his cybereyes and pocketchange, but would have hard time making out the same things through a crowd or rain. Also resolution isn't quite as good as with visible light, so the picture would be somewhat grainy.

For Sonar you want a ultrasound system.

The same reason you can't do it with ultrasound either.