[mythtv-users] OT - Antenna tuning/aiming
beww at beww.org
Thu Nov 2 22:54:57 UTC 2006
On Nov 2, 2006, at 3:33 PM, Brad Fuller wrote:
> Brian Wood wrote:
>> On Nov 2, 2006, at 2:32 PM, Brad Fuller wrote:
>> I think azap and the like will give you a signal strength reading. I
>> believe it gives you a BER as well, but I seem to recall reading that
>> that particular card does not give meaningful BER information.
>> Maximum signal strength may or may not equal best reception, because
>> you might have reflections that can be minimized by turning the
>> antenna slightly off peak. This is why the BER is a better indication
>> of signal quality for digital signals, but I don't think you can read
>> that directly from that card. Mine shows a zero BER no matter how bad
>> the signal.
>> (BER is the Bit Error Rate, in case you were not aware of that :-))
> Hey, thanks Brian. That works. Now I need someone to watch the numbers
> while I twist!
> (not that dance)
> Do you know why skew would matter on UHF?
If the transmitting antenna was plane-polarized a skew adjustment
would allow you to exactly match the polarity with your receiving
antenna. Most transmitting antennas have "beam tilt" which can
distort the signal a bit. Even if the transmitter was circularly
polarized a skew adjustment might allow you to null out a reflection
a bit since reflecting usually distorts the polarity somewhat.
Unless you are a fair ways from the transmitter I doubt that you
would actually see much difference though, but it might help in a
highly reflective urban environment like Manhattan. This effect would
be more noticeable on the higher channels.
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