[Elecraft] K3 TVI on 40 meters only

[Lynn W. Taylor, WB6UUT]

Since most DSL systems have multiple carriers, the only real distinction 
between "in" and "out" is that there is no carrier near enough to 
interfere with his receiver.

So, yeah, signals are radiating.  It's just not generating Mike's complaint.

The main point I was trying to make is that the wiring will never be as 
good as a straight CAT 5 run.

The installer is mostly looking from continuity from the DSLAM in the 
cabinet/pedestal, through the B-Box to the TNI on the side of the house, 
and from the TNI to the desired jack.

The pair from B-Box can run from one end of the feeder, through several 
other B-Boxes.  It can be tapped at the closest B-Box and run for 
hundreds of feet with no termination.

 From the TNI, the inside house wiring can have unterminated jacks in 
every room.

To a phone company (and the FCC) everything on the customer's side of 
the TNI belongs to the customer.  Running good shielded twisted pair and 
grounding the shield as best you can at both ends might help, with the 
rest of the house jacks disconnected at the TNI.

That assumes they're not using a POTS phone.  I haven't had one for years.

73 -- Lynn

On 8/26/2017 11:29 AM, Jim Brown wrote:
> On 8/26/2017 10:58 AM, Lynn W. Taylor, WB6UUT wrote:
>> First, he's reporting that his CW signal interferes with his TV, not 
>> the other way around.  It's not the VHDSL (probably) signal getting 
>> out, but his 40 meter signal getting in. 
> 
> Doesn't matter -- thanks to the principle of reciprocity, any passive 
> system that radiates will also receive, and all of that interface 
> (wiring, transformers, cable termination, Pin One Problem) is passive. 
> Take my post and substitute the word "receive" for "radiate." 
> Reciprocity is the principle that causes antenna gain and directivity to 
> be the same on receive as on transmit.
> 
> Further, electronics at both ends of these systems are noise sources, 
> and both are susceptible to interference, and both input and output 
> stages can be susceptible to interference. RFI often comes into audio 
> power amplifiers on their loudspeaker wiring, which couples back to the 
> input of the stage via the feedback network, where it is detected and 
> amplified.
> 
> Pin One Problems inject any current on cable shields onto the signal 
> common bus (traditionally called "ground"), where it gets injected into 
> gain stages at the whim of the PC layout artist, detected, and amplified 
> (or breaking up the digital signal). Study the tutorial material on my 
> website. Neil Muncy, ex-W3WJE (SK) published work documenting this in 
> 1994. In bar conversation, he observed that most RFI issues are caused 
> by Pin One Problems. In 2003, I published research showing that 
> statement to be entirely correct with respect to audio gear. Those AES 
> Papers are on my website. There's also tutorial material that's easy to 
> read.
> 
> Because Pin One Problems are putting the interfering signal onto the 
> signal return bus (signal ground), there's no logic between which gain 
> stage detects it and the cable it came in on. The RF could be on an 
> output cable, or on the cable for input #3, but turning the gain for the 
> input or for mic #10 could cause the RFI to increase in level.
> 
> 73, Jim K9YC
> 
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to kx3.1 at coldrockshotbrooms.com
>