Designer's notes
Modern technology can produce devices that produce 25 GW microwave pulses with a total pulse energy of 250 J. At 10 GW, a microwave pulse will fry transistorized electronics over a diameter of 400 to 500 meters. Even if you assume that the perfect coupling of bare, unprotected transistors by a perfectly aligned antenna is unrealistic for applications in the field, you still have the microwave pulse blasting all electonics over a wide (albeit somewhat smaller) area. While 25 GW, 250 J microwave sources are still rather bulky at TL 8, by TL 10 you will be able to fit them into a pistol. We know this because laser pistols would require similar or greater pulse energies and thus similar power handling equipment, plus all the beam generating and focusing equipment. Assuming a 1 cm wavelength and a 10 cm focusing aperture, you will be able to focus this into a 1 meter diameter spot at ranges of up to 8 meters. This will not only automatically fry anything electronic that is not in a totally enclosed and well engineered Faraday cage, it will set it on fire! (At this power level, fires will be ignited by high voltage sparks jumping across gaps between conductive wires.) The microwaves scattered from the target will kill all transistorized electronics within about a city block … phones, tablets, computers, smart appliances, thermostats, insulin pumps, pacemakers. God help you if you use it near a hospital.

While this level of indescriminate destructiveness may be appropriate for some settings, having people who just want to kill robots carry around a weapon of intermediate destruction in their pockets is not always the desired option. Hence, in this document it is assumed that the days of the silicon field effect transistor are near their end. Modern engineering has reached the lower size limit of silicon structures for micro-electronics and to get superior performace the boffins will switch to something else - something that just happens to be more microwave resistant. It is not like we are lacking for options: opto-electronics and plasmonics will reduce the length of wires over which voltage can build up from centimeters or more down to less than a tenth of a millimeter, and the 2D supermaterials people are looking at for the next generation electronics materials have extraordinary electrical and thermal properties that could allow them to be much more robust to transient voltages.

Be aware, though, that this is an explicit approximation that is being made here. GMs who want to use silicon microelectronics can do so, but should realize that when combined with radiofrquency weapons they will be all too easy to knock out.

Counter-Electronics Weapons

Counter-electronics weapons emit brief pulses of very high power microwaves, sometimes called an "Electro-Magnetic Pulse" (EMP). These pulses are silent, invisible, and generally imperceptable to those without advantages that allow them to sense into the radar or microwave part of the spectrum, except if they hit anything containing metal at close focus they will cause mad sparking (other excellent conductors, such as carbon fibers, superconductors, or graphene ribbons, count as metal for this purpose and may be encountered in futuristic settings). The microwave pulses have little effect on non-conductive materials, but can be collected by conductive wires that act as antennas and channeled into sensitive electronic components. This can temporarily or permanently disable electronic devices. Any machine, equipment, or character with the Electrical disadvantage will be Stunned if it fails a modified HT check ("upset"). Failure by 5 or more disables the device - it will remain non-functional until fixed. If the failure was by 10 or more, it will require major repairs before it will work again ("burnout"). Otherwise, flipping circuit breakers, replacing fuses, or just powering down and powering back on will suffice to bring it back to working order ("lockup"). This will take one minute and a successful Electronics Repair + 5 or IQ roll. Critical failures are one level more severe than the nearest non-critical failure.

The sparks created by microwaves that are collected by conductive surfaces and funneled across gaps or breaks in the surfaces can ignite flammables or detonate explosives. Anything with electrically-activated explosives must make a HT check at +10 to avoid immediate detonation. This includes characters with the Electrical and Fragile(Explosive) disadvantage. Electrical devices made out of flammable materials roll vs. HT with a bonus given by their flammability class (see page B433) to avoid ignition:

Electrical objects or characters that are powered down or otherwise disconnected from their main power supply roll at an additional +5 to avoid ignition (but not explosion). Objects that are not Electrical do not make this roll, but may suffer burning damage (see below) if they contain or are in contact with metal - which might ignite the object in the usual fashion for burning damage. If the object or character has both Electrical and the appropriate Fragile disadvanatge or flammability class, make separate HT rolls to avoid electrical malfunction and ignition/explosion.

Microwaves are difficult to focus. You need large dishes to get a tight focus at any reasonable range. Consequently, practical microwave weapons have beams that spread out as cones. At the listed range, the microwave beam has a width of one meter (one hex), at every multiple of that range the beam spreads out by an additional meter (2 m at between 1× to 2× the base range, 3 m at between 2× and 3× the base range, and so on). If the width of the beam is less than the width of the weapon's focusing aperture, the beam is focused, and coverges from the width of the aperture at the aperture to the width of the beam at the focus as a cone, then diverges from there as a cone going the other direction with the same opening angle.

When the beam spreads out, the microwave intensity drops and the pulse becomes less effective. Likewise, if the beam width is smaller than its target, the microwaves may miss critical parts or, if the waves are guided to the parts by antennas/wires/waveguides/resonant cavities within the casing, they will be less intense. Collecting these two effects, you get a bonus to resist given by:

The MAX function means take the larger of the two values. If the larger value is still negative, the bonus to resist becomes a penalty to resist instead. GMs may, optionally, make the SM of the beam more fine grained at closer ranges - a SM of -1 between 1×range and 1.5×range, for example, with the beam width being proportional to the distance from the listed weapon range. When targeting sub-assemblies, use the SM of the sub-assembly rather than the entire object. Microwaves will scatter from the area of incidence to affect electronics outside the beam's primary footprint. Even for things not directly illuminated by the beam roll a HT check, but with a HT bonus to resist equal to 2×MAX(target's SM, range modifier from the center of the beam spot to the device) + 9 - except if the device is connected to any point in the area illuminated by the beam by anything conductive it does not get the extra +9 bonus (this does not apply to omni-directional E-bombs, which have pulses that spread out in all directions so there is never anything outside their primary footprint).
Example:
In retrospect, the Supreme Leader should not have said what he did about the First Lady at the recent summit. Now the Republic of Bananastan is being blockaded by the world's global hegemon and superpower, with a destroyer parked just offshore of Bananastan's largest (well, only) port. Bananastan is now desperate for money, refined fuel, consumer goods, arms, food, medicine, and of course luxury goods for the Supreme Leader, his cronies, family, and many mistresses; meanwhile, Bananastan has loads of valuable oil just waiting to shipped out to willing buyers.

But the Republic of Bananastan has an ace up its sleeve. Before the recent troubles they had managed to acquire a single stealth drone with an E-bomb warhead. They have one shot to knock out the destroyer long enough to allow a flurry of smuggled goods to trade hands. The problem is that a destroyer is SM+11, which would give it a good chance of surviving even a close range E-bomb without any damage persistent enough to allow any boats to get through. The radar mast and antenna assembly, on the other hand, is only SM+7. Without radar to identify targets, or to guide its shots, Bananastan might be able to get quite a number of boats past.

So, one night, the stealth drone does its stealth thing and sneaks up close to the destroyer, and in particular, right over the radar mast. BOOM! The E-bomb goes off, unleashing an EMP with a HT-25 blast. The destroyer, at SM+11, gets +22 to resist. Not surprisingly, its lights flicker for a few seconds before all the electronics come back on-line. Well, not all the electronics. Because the radar was deliberately targeted, it gets a separate roll using its SM of +7, for a +14 bonus. This is a net -11 to the HT roll, and the radar fails by enough to burn out completely. The destroyer is now blind. Dozens of smuggler ships now start a desperate run in and out of port, hoping to cross the line of blockade before the sailors on the destroyer complete their damage control and get the radar working again.

Microwave beams pass through walls, clothes, and between 10 to 100 cm of rock and soil (depending on moisture content) without significant attenuation. Non-conductive armor of any sort, including cloth, leather, modern ballistic armor, and most futuristic armor, offers no protection against microwave bursts. Metal and other good conductors, on the other hand, reflect microwaves. The thickness does not matter - a thin layer of aluminum foil will do as good a job of reflecting a microwave beam as thick armor steel or a mail suit. Metal suits, armors, or barriers that are not specifically designed to stop microwaves are not a perfect defense, however - microwaves will leak through openings and the interior is likely to act as a resonant cavity or waveguide that can actually increase the intensity of some frequencies. Further, antennas or metal cords leading to the outside can pick up the microwaves and funnel them inside the suit. Wearing a full metal suit or armor usually provides some protection, however. These will provide a +8 bonus to the HT roll to resist unless the character has active Scanning Sense (radar), Scanning Sense (imaging radar), Telecommunication (radio), Accessory Perk (radio), or any other antenna; a power cord leading outside the suit; or any conductive communications cable leading outside the suit (such as coax cables, telephone cords, or ethernet cables, but not fiber optic cables). A partial suit of metal will give a +3 HT bonus. Suits or armor specifically designed to stop microwaves may provide a higher bonus. Metal barriers or metal meshes with a grid spacing of less than a centimeter will also provide a bonus of similar to that of a suit with the same coverage, all the way to complete immunity for a fully enclosed cage of metal around the character or device without any antennas, cords, or centimeter-sized or larger holes to the outside (called a Faraday cage).

The usual defense against counter-electronics attacks is the Resistant advantage, which can represent circuit breakers, surge protectors, surge arrestors, robust electronics, isolated radio or radar systems, metal casing, or electronics located inside of a Faraday cage.

From TL 6 through TL 8, electronic components have become more and more sensitive to the transient high intensity electromagentic fields produced by counter-electronics devices. As a rough guideline, use the following for electronics without special engineering to resist counter-electronics effects:

Very high powered microwave beams will deposit enough energy in flesh to cook it. The sparks created by such beams can also cause thermal burns to anything with metal in it or touching it. The GM may rule that some non-metalic wet, heat sensitive but non-living materials (such as ice, or maybe zombies and vampires) will also take damage, or that uniform sheets of metal without gaps are unaffected. Non-metalic dry materials, and wet materials that will not be appreciably harmed if heated past the boiling point of water, will not be harmed by this effect. If the HT penalty, including the penalty from the microwave source itself plus modifiers for range (but not size) and metal shielding, is worse than -27, cooking or spark damage may occur:

Note that metal shielding does not necessarily apply to the metal itself - a knight in mail armor will be protected from cooking by his armor, but the sparks from the armor can burn him and ignite his clothes. Metal that has lots of gaps and nearby adjoining sections, or creases or wrinkles or projections or dimples (such as mail or scale armor, or aluminum foil that has previously been crumpled) does not get any protection for its metal-ness. Smooth sections of metal that has minimal gaps or joins (such as plate armor) rates +8 to the HT modifier for determining damage on the table above. Smooth, uniform sheets of metal over a wide area will be un affected by microwaves and just reflect the beam instead. Damage is per hex exposed to the beam. Small targets (SM < 0) will have their damage reduced proportionally to their linear measurement from the Speed/Range table, compared to SM 0 linear measurement of 2 meters. Similarly, SM+1 targets can be considered to occupy 1½ hexes, for a +50% increase in damage. This damage can usually be considered toxic to non-metalic objects (although, as mentioned, some non-living but wet and heat sensitive objects may also be damaged), and burning to anything with metal in it or touching it. The burning damage may also set fires, in addition to the rules for igniting electrical components.

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