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Topband: 1819 Spur

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Subject: Topband: 1819 Spur
From: (Tom Rauch)
Date: Tue, 11 Dec 2001 11:14:23 -0500
Thanks for all the help to everyone. The spur on 1819 is gone for 
now, hopefully permanently.

Now we have three NDB's in the SE USA and two more BC 
stations to go, all were reported in he past few days directly to field 
offices working in the area of the transmitters.

If anyone is bothered by an airport NDB, please call it in to the 
ARRL or the FCC. You can identify an NDB by the constant 
repeating of three letters (no numbers). They sometimes appear as 
an exact image of the actual CW ID, since the transmitters have 
separate carrier and tone oscillators in an early stage. 

These transmitters are below the BC band, and generally have NO 
filtering in any high power stages of the transmitters. They stupidly 
depend on linear operation of several stages to NOT generate 
strong harmonics, and what harmonics are there are supposedly 
suppressed by a loading coil!!!

That's right, not a single low-pass filter anywhere after the 
transistors in the output (which is clamped by zener diodes for 
lightning protection)....and they are almost never tested properly.
73, Tom W8JI 

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