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Old 6-May-2019, 3:02 AM   #16
Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,565
Originally Posted by Johnsonbrits View Post
I have a network router and OBI VoIP modem powered and physically close to the TV and Laptop Hauppauge stick. Removing the AC power from the same AC outlet and moving to a separate feed showed a reduction in pixalization for K0FB - Interesting!

I then powered down the laptop with the Hauppauge TV stick and boom, up came K0FB with minimal pixalizations. Not having the Hauppauge signal monitor I cannot read the SNR. However the TV signal monitor shows a consistent signal strength of "normal - yellow" vs Fox on channel 7 of "Good - Green".

I'm extremely pleased to finally receive VHF-Low channel 3 fairly consistently. I then purchased an EMI/RFI AC adapter from Radio shack for the television receiver but still receive noise which I'm thinking is also RF induced from the AC power wiring going to the laptop and other switching power supplies since as I move the AC power lines around by the TV pixalization pops up until I move the power cable to another location

Any thoughts on how to eliminate the noise induced into the AC power wiring? I was thinking of a 6 foot shielded AC extension cord to keep the various power supplies physically removed from the TV receiver would help?
Thank you for the update, Peter. Glad to hear you were able to get them to put the transmitter back on the air.

You were able to reduce the noise interference that was reducing the SNR of the channel 3 signal, so you are almost there.

It is possible that you have some interference that is conducted through the power line, but you most likely also have some radiated (through the air) noise interference that is picked up by the antenna.

First, make sure that the coax is grounded with a grounding block that is connected to the house electrical system ground; it might help. Next, use a portable battery operated radio tuned to a vacant channel on the AM broadcast to hunt for sources of radiated noise interference, as I mentioned in post #7. Most AM portable radios have a loopstick antenna that is directional which will help you locate the interference source.
If you can not measure it, you can not improve it.
Lord Kelvin, 1883

Last edited by rabbit73; 6-May-2019 at 3:12 AM.
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