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#4
February 18th 11, 01:39 AM
posted to rec.radio.amateur.antenna
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No comment three antennas - duplex
On 2/17/2011 6:22 PM, J. C. Mc Laughlin wrote:
K1TTT has nailed it! Effecting a null that is deep enough to produce something useful is difficult. In any case, the patent examiners will find that the telephone people did something like this a long time ago. 73, Mac N8TT J. C. Mc Laughlin Michigan U.S.A. Home: One big difference is that the hybrid in a POTS phone doesn't want a deep null. They want enough left of what is called "side tone" to give feedback to the ear with receiver on it. If you don't they are uncomfortable and also think the call has been dropped. It would be in the -10 to -30dB range I'd guess. On the other hand the null for this antenna array would need to be maybe 90dB or better to be really useful. Maybe with processing it could be done with less, but I'd have to say, I don't know. tom K0TAR |
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