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Old December 26th 05, 06:30 AM posted to rec.radio.amateur.antenna
Dave Platt
 
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Default Standing Waves (and Impedance)

In article ,
Cecil Moore wrote:

I have run the IC-706 all up and down the channel 3
60-66 MHz frequencies while in College Station, TX
and cannot hear the audio anywhere.


For what it's worth, I'm able to use my Kenwood TS-2000 to tune in the
audio carrier of our local Channel 2 station. According to my cheat
sheet, 2's video carrier is at 55.25, with audio carrier 4.5 MHz
higher... hence 59.75 MHz. It seems to tune in best on my radio at
59.745.

Your channel 3 audio carrier ought to be at 61.25 + 4.5 = 65.75 MHz.

I don't have my service monitor handy so I can't tell for certain what
the peak FM carrier deviation is, but it's definitely broad enough to
cause serious distortion on my TS-2000 (which is set up for ham FM
deviations of around 5 KHz). My recollection is that TV audio carrier
deviation is similar to that of commercial FM broadcasts.

It's possible that your IC-706 isn't willing/able to lock onto a
carrier with such a high deviation, perhaps? or perhaps it needs to
be switched manually to a "wide FM" mode to do so in this frequency
range?

--
Dave Platt AE6EO
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