[RFI] RF slowing down upstream cable modem data

[Jim Brown]

On 11/8/2018 11:53 AM, Matt NQ6N wrote:
> I've added substantial amounts of ferrite to the CATV coax, ethernet cable
> and power cable.

Remember that ferrite chokes work by adding a high resistive Z in series 
with the common mode circuit, and that resistance is maximized by 
winding enough turns that the resulting choke is broadly resonant where 
the problem is present. A #31 core clamped onto a cable without winding 
turns is resonant around 150 MHz and will look like only a few Ohms. 
Depending on the size of the clamp you're using, you'll need at least 
4-5 turns to make it work on 40M.

Chokes should be applied to every cable connected to the modem, 
including Ethernet to a wireless router or switch and the modem's power 
cable.

More details in http://k9yc.com/KillingReceiveNoise.pdf  When reading, 
remember that antennas work in reverse -- that is, they receive like 
they transmit. :)

73, Jim K9YC