EMRFD Message Archive 11448

Message Date From Subject
11448 2015-08-08 06:04:42 jorschei ACTIVE ANTENNA

I experiment with capacitive active antennas indoor and with loops. I confirm thad the whip type antennas are indoor more sensitive for electric noise. The best results I got  with the closed loop aluminium strip 120 cm diameter loop antenna against the loft roof. I was able to receive from aprox 200KHz up to 144 MHz the ham stations. Good data and where to think about to cover the design pitfalls are in the AKTIVE ANTENNEN book written by Eric T Red and DJ9DV. In German.

It schould be posible to scale down those active antenna designs for a lower 3.3 volt power voltage with low noise gain blocks and in front the high impedance transformer FET.

But with lower (large signal) IP3 specification.

An diode 1N4009  in the antenna for overvoltage protection is not good and and gif intermodulation with strong signals. Red adress dis problem to.

In the PE1KTH files my indoor loop in use for several years.  In Dutch.

73'Joris  PE1KTH