Info

The only step left is to provide dc voltage for the amplifier. This is done through a dc isolation choke of approximately five times the collector load impedance. Some base to ground dc connection should also be pro vided to eliminate high standby leakage currents and to prevent the rl input power from biasing the transistor off (loss of power gain will result). See Fig. 13.

dc by-pass

8ase dc return (may also low value resistor)

dc by-pass

8ase dc return (may also low value resistor)

collector isolation choke

Fig. 13I

collector isolation choke

Fig. 13I

The collector choke should be heavily bypassed, on the dc side, to eliminate oscillations and rf feed-through into the rest of the system.

Practical VHF and UHF Amplifiers

I am going to describe several simple designs that will make any VHF or UHF transistor play quite well and explain how you can optimize them for best performance.

This amplifier will work with any VHF transistor whose power output is between 3 and 40W.

Some of the more common transistors that can be used and their respective power gains are listed in the table.

Power

Power

(Mfr.)

Type

Output

Gain

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