160 M Interference Report, from NR1R in Reading, Ma.

----- Original Message ----- 
From: Dxhogg@aol.com 
To:   rfi@contesting.com
Sent: Tuesday, December 21, 2004 7:33 PM
Subject: [RFI] RFI FROM AN ANTENNA TUNER

http://lists.contesting.com/archives/html/RFI/
2004-12/msg00019.html

I have been experiencing some very strange 
noises on all the ham bands some come and 
go but mostly 20 M and 160 M as it turns out .

The 160 M antenna tuner I use is a 1945 model
built by "Technical Materials". It is a 5 kW 
open wire line tuner was the culprit.  

All the interconnecting internal wiring were 
made from braid and were acting like rectifiers.

I have replaced it with #10 silver plated wire  
and all the noise has disappeared.
    73  ray  nr1r


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----- Original Message ----- 
From: Dxhogg@aol.com
To:   rfi@contesting.com
Sent: Sunday, December 26, 2004 8:57 AM
Subject: [RFI] COMM0N MODE NOISE OBSERVATIONS AND REPAIRS 


I had posted about a week ago about common mode  
noise and what I had thought was a really awesome  
"repair". Well, the repair really works but along 
the road of determining what was really at play 
creating all the different noises I have discover-
ed all of the problems in the station was of poor 
infrastructure. 

I had originally wired the operating position all 
station grounds and interstation cabling about 18 
years ago. Well to put it in simple terms it was 
all junk. 

Wall warts, braided cable for grounds, and poor 
quality coax were the real culprits. 

Pay extra attention to ground loops -

- Wall warts are a prime cause of ground loops. 
  Cut all the cables off the warts and use only the 
  cable and use a good quality 10 amp power supply 
  for all the ancillary station equipment. 

- Multiple antennas and feed lines should all be  
  kept galvanically separated from one another till 
  the cables are connected at your main station 
  bulkhead. What I mean by 'separated' is don't use 
  the ground for a 160 meter "inverted L" as a tower 
  ground etc. 

Look at your station layout in a ground loop aspect; 
you will be amazed [th]at isolating these problems 
[will] clean up the noise floor. I had a terrible 
noise on 160 M that seemed to follow the resonant FREQ 
of the transmit antenna when I would disconnect the 
open wire feed from the tuner the noise on the receive 
antennas would disappear..... 

Well it turns out that in 1945 when Technical Materials 
Corp. built this unit using braid as interconnecting 
leads was cool - not so, my tuner was a rebroadcaster....

All the junk braid replaced with 1/4 inch tubing and 
quiet bands again ... 

This [should be] a wake up call look at your station 
your neighbors WiFI stuff my be heard because of a 
rectifying [junction] in your station... simple things 
like coax connectors with the shield not soldered 
correctly will cause a hell of a lot of problems.

dx  on   Ray  NR1R 

Reading, Ma Daytime Station Allocations - Position Plots

Plots of stations licensed to operate (or proposed to operate) during daylight hours.

The data appearing adjacent to each plotted point is in the form:

         Callsign/Freq (in kHz)/Power level/Distance (to the blue star) 

New stations are identified as "New" in the callsign slot.

Zoomed image, close up, no roads

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