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diversity antenna revisited
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David Cutter
Chris DUAL POLARISATION ACTIVE ANTENNA I have one of these antennas and I want replace the whips with a pair of orthogonally placed large terminated loops, ie flags. Do you see anything that might be a problem with bringing these together? 73 David G3UNA
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Chris Moulding
David,
The amplifier in the Dual polarisation active antenna is the same as the HF active antenna i.e. a balanced push-pull FET input amplifier. It should work OK with a large terminated loop element. You will have to place a suitable resistor (the same value as the termination resistor) across the inputs to correctly terminate the loop element as the input impedance of the amplifier is in the megohm range. I would be interested to hear how it works, it sounds like an interesting project. Regards, Chris
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David Cutter
Thanks for the prompt reply, Chris. It is usual to use a high ratio transformer to get to 50ohm from low band loops but this also transforms the signal from its already weak state. By using your boxes I get a buffer which is resilient to common mode noise with no transformer loss. I don't know how much gain I will need, how much gain can I expect from the active antenna terminated with 1k? David G3UNA
On 21 March 2019 at 13:40 Chris Moulding <chrism@...> wrote:
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