They exhibit fast response through the UHF region, and are constructed from proven transmission line, gaseous discharge components, silicon components, and can be subjected to many transients

Spikeguards have been organized into various types that will optimize those protective characteristics required.

The FCC-250 series (description of the part numbering system) are rated at 10,000 amperes for a duration of 10 microseconds, This series is available in a number of dc breakdown voltages varying from 75 volts to 2000 volts. This series has a pulse breakdown varying from 1000 to 3000 volts for a pulse rise time of 1 kv/nanosecond. The impedance of this series is approximately equivalent to 2.5 picofarads in shunt with the transmission line load.

In the event that the total tolerable VSWR is specified for the entire coax-to-antenna system, a determination can be made if the addition of a Spikeguard will exceed the limit. It is merely necessary to specify the VSWR and impedance of the system without the Spikeguard, and the above analysis can be carried out.

The FCC-350 series is rated at 20,000 peak amperes for a 10 microsecond duration. This series is available in various breakdown voltages varying from 90 to 20,000.

The 250 and 350 series are extremely fast in reacting to transient voltages. For dc trip voltages of 1 KV and higher the overshoot voltages of transients having a ratio of 1 KV/nanosecond is minimal since the trip voltages is achieved in approximately 2 nanoseconds. The impedance of these series are approximately equivalent to 3 picofarads in shunt with the transmission line load.

The 450 series are constructed from proven silicon components that are in turn encased in epoxy.

They can be provided with clamping voltages varying from 6 to 300 volts, The 6 to 20 volt units are capable of sustaining 70 amperes of peak current for a triangular pulse having a 4 microsecond pulse width. From 20 volts and up, the units have a decreasing current capability, with the 300 volt unit capable of sustaining 5 amperes of peak current for 15 microseconds.

The dc impedance in the nonconducting mode is equal to or greater than 5 megohms,

The clamping voltages are achieved in approximately 1 nanosecond for transients having a risetime gradient of 1 megavolt/microsecond. Of particular importance is the fact that these units exhibit a capacitance of approximately 2 picofarads,

Since these units operate extremely fast and have low capacitance, they will provide transient protection for sensitive semiconductor components, particularly, integrated circuits, such as TTL, ECL, DTL, MOS, and MSI. Due to the fact that they have low capacitance these units can protect not only power supplies, but also input and output data lines, without degrading the data transmission operating characteristics, by excessive capacitive loading.

Typical dimensions of these units are 0.6" long by 0.6" wide by 0.4" high.

The FCC 450 series are also packaged in coaxial connectors to protect receivers and transmitters from transients. They exhibit fast response through the UHF region by clamping in approximately 1 nanosecond when subjected to transients exhibiting risetime gradients of the order of 1 megavolt/microsecond. These units also have a distributed capacitance of approximately 2 picofarads.

For example, the FCC-450-10-(connector type) is used to protect receivers and clamps fast transients to 10 volts peak.

Typical VSWR values for the type N, C, BNC and TNC connectors are
as follows:

The 450 series that clamp up to 300 volts are capable of protecting transmitters up to 200 watts.

An improved 450 series has been developed, and is designated the 450B series, These units have improved VSWR characteristics.

In order to obtain optimum transient protection the two units must be separated via the coaxial cable by at least 50 feet for a slow transient having a risetime gradient of 20 kilovolts/microsecond; and by 3 feet for a fast transient having a risetime gradient of l megavolt/microsecond.

The above hybrid combination provides optimum protection of both transmitters and receivers.

Even though the 250/250B/350/350B series will have some overshoot, those units used for transmitters up to 100 watts will still clamp at 1800 volts or lower, for a transient having a risetime gradient of 1 KV/nanosecond, and 1000 volts or lower for a transient having a risetime gradient of 20 kilovolts/microsecond.

In most instances these overshoot voltages will not cause failure of an antenna or transmission line since they will only last for 2 nanoseconds for the 1 KV/nanosecond risetime gradient and 50 nanoseconds for the 20 kilovolt/microsecond gradient

The energy levels finally permitted to arrive at a transmitter or receiver during a transient will be well within the safe levels of 450 series normal operation.

As transmitter power output levels approach one kilowatt the 250/250B series overshoot performance is nearly equal to that of the 350/350B series. The Spikeguard clamp voltage for a one kilowatt transmitter would ideally be about 1100 volts dc, in order to prevent inadvertent firing of the Spikeguard due to transmitter power and antenna VSWR. An 1100 dc volt rated 250 series will only overshoot to 3000 volts before clamping a 1 KV/nanosecond gradient transient This overshoot will only exist for a period of about one to two nanoseconds. Even for a 100 watt transmitter the condition is not much more severe. A 100 watt transmitter will be rated to clamp at 230 volts dc. A 1 KV/nanosecond gradient transient will cause an overshoot voltage of about 1500 volts. This will only permit the overshoot to exist for a period of approximately two nanoseconds. The energy permitted to exist during either of the two examples would not exceed 200 microjoules, which is insufficient to damage 100-500 watt transmitters.

Therefore, transmitter protection is recommended as follows: For transmitters up to 100 watts output, a hybrid combination of a 250/250B series be placed at or near the antenna, and a 450/450B series be placed at the transmitter is recommended. For transmitters of 100 watts or greater a 350/350B series unit placed near the antenna is recommended.

The 250, 350, and 450 series protectors have also been configured for protection of telephone, and computer data lines Protection is offered for 1 to 150 pairs of data lines. Installation is convenient and economical through the use of a Quick-Connect Terminal Block providing junction points to the protectors that shunt the lines to ground.

The Quick-Connect Terminal, strips, connects, and trims wire in one operation. The terminals are designed to make a positive connection to unskinned 20-24 gauge conductors, or 18 and 19 gauge skinned wire, and accomplish this through a spring tensioned terminal clip, and Quick-Connect tool combination.

The procedure for installation of a data line is to just hook the unstripped conductor to the top of the clip. Then using the Quick-Connect tool, push the wire down into the clip. This action automatically strips the insulation, forms an electrical connection, and cuts off excess wire. All of the above in one fast operation.

The overall data line protector comes with a 250, 350, or 450 type Spikeguard installed between each terminal strip and the ground strip. The ground strip runs the entire length of the block and has convenient bolt holes to permit mounting and attachment to any earth connection available. The position of the ground strip permits very short leads, minimizing inductance in the installation.

The entire terminal block can also be supplied in a metal housing, if no convenient terminal box is already available.

Fischer Custom Communications power line transient protectors are especially designed to achieve optimum suppression of high energy nanosecond risetime transients.

Several types of powerline protectors are available. Two versions are as follows: The FCC-120-P Model plugs into the free electrical outlet next to the one your equipment receives its power. The FCC-120-P is a 120 VAC (60-400 Hz) power line rated device, which is capable of sustaining a transient peak current of 1000 amperes for 5 microseconds, and 100 peak amperes for 100 microseconds.

Transients varying from 400-100,000 peak volts will be clamped at 400 to 600 peak volts. This type of suppressor is constructed from a metal oxide semiconductor, which clamps transients having risetime gradients of the order of a megavolt/microsecond.

The FCC-120A-P is capable of withstanding 2000 peak amperes for 5 microseconds, and 200 peak amperes for 100 microseconds. All other characteristics are as previously stated.

The other type of power line protector not only enables optimum performance of the metal oxide component but increased overall circuit protection by the addition of common mode chokes placed in series with the power line between the metal oxide components and the equipment being protected. This circuit configuration permits the metal oxide component to have common mode inductive impedance in series with the load, thus increasing its ability to clamp. Clamping under these conditions will occur with the transient delivering minimum current to the load being protected. Transients varying from 400-100,000 peak volts will be clamped at 300 to 500 peak volts.

1. The common core inductor toroidal windings will not suffer core saturation, and voltage drop when passing the high power line currents.
2. The inherent capacitance of the metal oxide components, and the common mode chokes create an LC filter that will constantly provide protection from lower level transients and interference caused by common mode currents.

Installation is convenient, just plug the male receptacle of the suppressor into a single phase, third wire grounded, wall outlet. Then plug the equipment to be protected into a grounded socket provided in the suppressor.

Special units such as three phase circuits, greater transient current capability, or greater continuous current capability will be quoted on request.

Installation information is extremely convenient All that is required for the coaxial types is the insertion of the suppressor assembly at any convenient coaxial cable connector near either the antenna terminals, or near the transmitter and/or receiver terminals.

The data line 450 series must have its terminals soldered across the terminals to be protected.

The Quick-Connect data line Spikeguard assembly comes with the suppressors already assembled. The only tasks for installation are the mounting of the block wire connections and routing of the leads.