[Elecraft] Active Noise Canceling for KX1

[W0rw at aol.com]

   i just ran a test of the Philips SHN2500, in-ear noise canceling 
headphones (they are earbuds).
   The operation of the KX1 outside can be difficult under high ambient noise 
conditions if your earbuds don't fit well. i don't have really good earbuds 
so i wanted to try this active noise canceling system. i use my KX1 while 
walking around outside and have had trouble with truck and train noises.
   Yes, it comes from China (through Walmart, SKU 2661602879).
The technical ratings are sketchy at best, > 10dB Noise Reduction at 300Hz.
   The earbuds come with 3 different sized ear caps. They are just rubber 
grommets,
not very special.
   They really do have a built in microphone that is on the outside of each 
earbud.
i took the amplifier apart and they have extra shielded wires going up to 
each microphone. The small summing amplifier adds about 3 dB of gain when it is 
turned on, and the noise reduction is noticeable when trying to receive weak 
signals in a noisy environment.
   The amplifier runs on a single AAA cell and inside it has balancing pots 
you can optimize. If the battery should fail, it does work in the by-pass mode 
when the switch is off.
i don't think they would out perform some well fitting earbuds.
Price is about $25 USD.
Paul w0rw<BR><BR><BR>**************************************<BR> AOL now 
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