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Old March 18th 08, 09:21 PM posted to rec.radio.amateur.antenna,sci.electronics.design,sci.electronics.basics
[email protected] dirskyster@gmail.com is offline
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First recorded activity by RadioBanter: Mar 2008
Posts: 3
Default Do receiver antennas need matching or not?

On 3月15日, 下午7时11分, billcalley wrote:
Hi All,

I always hear that antennas have to be matched to their radio, but
in receivers (such as FM and shortwave radios) I see mostly long
random length antennas used, and these antennas -- be they a
telescoping whip or a long wire out a window -- are used over some
really wide bandwidths. How is this possible if an impedance match
must always be maintained for radios? And since there cannot be a
good match over such wide bandwidths with any (typical) wire antenna,
what is the downside to using these completely unmatched long antennas
for receivers? (Poor gain patterns with lots of nulls? Lower
sensitivity due to bad noise figure or gain match for any LNA or
frontend amp? Degraded overall antenna gain)?

Thanks; I'm very confused on this subject!

-Bill



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