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FET VHF Preamplifiers

Angle Linear has been producing FET preamplifiers longer than any other product. Even in this age of GaAs FETs, we still produce junction FET preamplifiers because of their low noise figure, lower gain, good dynamic range, inherent narrow bandwidth and excellent reliability.

These preamplifiers have about a 1.5 dB noise figure up to about 170 MHz and about 12 to 13 dB associated gain, which in many cases is all some systems really need to bring their performance up to optimum. The noise floor at some radio locations, especially near cities, is high enough below 170 MHz that using GaAs FET or PHEMT preamplifier is sometimes unnecessary.

These FET preamplifiers are unconditionally stable and have hi pass matching on the input and bandpass matching on the output. This type of matching gives this design of preamplifier a very narrow bandpass response eliminating or at least reducing the need for extra band front end pass filters in many cases. The 3dB bandwidths are typically about two percent which is relatively narrow considering the low noise figure of these amplifiers. We produce these FET amplifiers on any frequency up to 170 MHz. Above that, we recommend our PHEMT preamplifiers.

Every preamplifier has over and reverse voltage protection. External and internal high voltage transient suppressors provides 40kV, 1 micro sec. pulse protection. Operation is from +9 to +16 VDC with higher voltage options available. Filtering on the DC terminal provides >70 dB attenuation from 20 MHz to several GigaHertz. DC current requirement is typically 17 mA.

The package is the same as used in our PHEMT preamplifier line, in fact we use the same enclosure. Construction is rugged: an irridited aluminum enclosure with stainless steel hardware throughout. Twenty screws attach the covers and give maximum shielding for the most hostile RF environments. Tri-Metal connectors have ptfe (Teflon) dielectric with gold pins and are available in type N, SMA (ss) BNC and TNC.

Dimensions: 1.5"x2.5"x 0.7". Mounting and connector positions give maximum versatility for high density rack panel mounting.

To order: Part number = F plus frequency of operation (MHz), type of connector. Example: F160NT; 160 MHz, N connectors, (T) Top mounted connector version.

F1217NT, tunable from 120 to 170 MHz, 12 db gain typical, Return loss: output >15 db, input 5 to 8 db. Tuning access on bottom of unit, use insulated tuning tool.

Angle Linear also produces: Hi intercept PHEMT & bipolar preamplifiers, Receiver Multicouplers, Preselectors, Window Filters, Duplexers, Notch Filters, FET preamplifiers, Bias Tees, and does developmental work in receiver front ends.

Specifications subject to change without notice.