PR20 ON-OFF Switching Suggestion

Depending on your particular application and intended frequency, you may wish to use a DPDT power switch with one pole controlling voltage and the other pole connecting the input and output of the PR20 when the DC supply voltage is in the “OFF” position. This setup is very practical when you want to switch the preamp in and out of a receiver antenna line. ALL RF connections to the switch should be as short as possible. Use good quality miniature coaxial cable.

STRONG SIGNAL OVER-LOADING

If you live in a situation where there are very strong nearby stations, you may experience overloading of the receiver to which the preamp is connected. This is especially true for small hand-held radios - after all, what do you think they leave out to make the size small? Front-end filtering components are large, but they serve a needed purpose in high RF environments. Unfortunately, there is little you can do except to add the missing filtering. Digi-Key (1-800-digi-key) sells the TOKO line of helical filters which are excellent. Expect to pay about twice as much as you paid for this preamp!

PR20—10