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schroff

join:2003-08-28
San Antonio, TX
reply to schroff

Re: [TWC] 723-MHz interference?

I am certain that I have reached the end of what may be accomplished, but what I have found is the higher the signal level I can provide (+18dBmV with >36dB SNR) to any of these tuners, the better those effected channels are BUT the signal is the too high for the tuning adapter to operate reliably. Adding attenuation to get get my low to high of mapped frequencies at +2.1 - +8.2dBmV, all greater than 36dB SNR is the most workable balance, but KENS is still often unwatchable through any PC tuner. I just do not see why internal screen tuners and TWC cable boxes are immune to this.

I have added a tilt compensator which reduced my low to high frequency level difference from 18dBmV to 8dBmV.

I have also added an 860mHZ Low-pass filter immediately in front of the tuner input. This seems to have lessened the occasional one-line screen disruption on other channels.

With all that TWC just sees the numbers and says I'm good.



DrDrew
That others may surf
Premium
join:2009-01-28
SoCal
kudos:15

The PCs could be generating a RF signal around 723 Mhz or some multiple (2.8 Ghz, 1.4 Ghz, 360 Mhz, etc.) of it that is interfering with the internal tuner...


schroff

join:2003-08-28
San Antonio, TX

That may not explain why this also seems to exist on ethernet or USB connected hardware.



DrDrew
That others may surf
Premium
join:2009-01-28
SoCal
kudos:15

723 Mhz should be limited to low power TV stations and translators. Got any of those around your neighborhood? FCC database searches don't bring up anything.


schroff

join:2003-08-28
San Antonio, TX

No, nothing near me and geographically, the others I have heard from in San Antonio are all over the place.