[RFI] Keyboard RFI

[Dale]

Charlie,

While the hash noise must truly be bad news, that 50V on the CATV line could be even worse.  Is that 50VDC or 50VAC?  If it is AC, it sounds as if there is significant leakage current (or coupling) within a power supply that is operating  some part of your CATV systems.  If that potential is on the cable coming from the outside world into your house. you need to advise the system operator ASAP.  The fcat that you can draw an arc means you have a very definite safety hazard present.  If there is 50VDC on the cable, then you still have  safety issue, but that would indicate that some power supply voltage has been coupled onto the shield of the cable.  That is probably not by design.

73, Dale
WA9ENA 


-----Original Message-----
>From: Charlie Gallo <Charlie at TheGallos.com>
>Sent: Aug 22, 2013 12:03 PM
>To: rfi at contesting.com
>Subject: [RFI] Keyboard RFI
>
>Hi Gang,
>So, got the SW Radio, and have found some interesting RFI sources around the house, have suppressed some, have a tech call in on another (the cable TV line has HORRID noise on it low, and if you lift it off the ground, has about 50volts potential to ground (yes, it'll draw an arc!!!))
>
>One odd thing I found - every keyboard around the house (and I have different brands from cheap to Unicomp Model M keyboards) has horrid RFI _IF_ you are close to it (like the hand held within say 6-9 inches)
>
>Any clues to a GOOD keyboard that doesn't broadcast like mad (they are all wired USB keyboards)
>
>-- 
>73 de KG2V - Charles Gallo
>Quality Custom Machine-shop work for the radio amateur (sm)
>
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