Topband: Noise and reception

[Donald Chester]

Thank you to all who have commented on the electronic noise cancellers by 
Timewave and MFJ.  I'm still browsing the archives.

My tx antenna is a full size quarter wave vertical with base insulator and 
120 quarter wave radials.  While it is a fantastic transmit antenna, it is 
pretty sorry for reception.  I built an indoor, rotatable, 5' X 5' shielded 
loop that worked FB when I had the shack in the house (with non-metallic 
roof).  When I moved to my separate shack about 10 years ago (with tin roof) 
the loop became almost totally ineffective - almost as noisy as the 
vertical, and all the signals null at exactly the same point as the noise.

This summer I constructed a small square horizontal receiving loop fed 
diagonally at each corner  with open wire line, as described in the two 
articale in Sept 95 QST.  Although I occasionally get good results with it, 
for the most part this antenna was a waste of time, usually giving little 
noise improvement over  my rotatable loop, while delivering so little signal 
that internal receiver noise becomes a problem.   Has anyone had any kind of 
good results with one of these antennas?  So far I have found no  discussion 
in the archives.  Have not yet tried flag, pennant or ewe.

Over Xmas holiday, I put up a 400' terminated Beverage, 10'  high.  It seems 
to be my quietest antenna, although not too directional.  However, it is no 
panacea, picking up certain types of noise almost as strongly as it comes in 
on the vertical.

If I do attempt to use one of the noise cancelling gadgets,  I will try to 
reduce the noise pick up on the Beverage, using a separate noise antenna 
near the power lines.

BTW  I have found an inexpensive noise sniffer at Radio Shack.  They have a 
little portable AM/FM radio with aircraft band (108-132 mHz AM).  Costs 
about $30.  I  can usually pinpoint noise right down to the pole by riding 
and walking around, listening on the aircraft band.  However, the present 
noise source has been more elusive.  One problem is, driving down the road, 
the ignition and alternator noise in every vehicle I own completely masks 
the noise, and people drive like such maniacs that  I am afraid to  use my 
bicycle for this.

73, Don K4KYV





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