[TenTec] TenTec Digest, Switching Supplies

[Don Allen]

Most of the older style Linksys routers, such as the WRT54G and WRT54GL 
were, and still are, notorious for creating hash... not only their 
switch mode wall warts, but the Ethernet outputs did not include any RF 
bypassing. Thus, the Ethernet cables connected to the router acted like 
long antennas propagating the hash everywhere.  Although you can find 
linear wall warts at most suppliers, I've found the most reliable source 
for linear wall warts is Jameco Electronics - a company that I was 
surprised was still in business.  Years ago, you used to see Jameco ads 
everywhere.

73
Don W9CW


On 9/8/2012 3:30 PM, N4be_Jim wrote:
>> Sorry to drag this out but its a problem.  Noise generated by switching supplies... I used the TenTec switcher that came with the Orion and it was clean.  The build in switcher in my Icom 775 is also very clean.  They are good design.  But go buy a network router or switch, or have a cable box installed in your house, or even in your neighbors house, and you may get a lot of noise across the HF spectrum, with strong warbly carriers at regular intervals. The switching supplies are basically an oscillator that drives the power devices to produce the output voltage.  Harmonics of that oscillator cover the spectrum.  Wall warts are terrible sources, such as those used to power routers or cable boxes.  I had to replace the wall wart on my router with a traditional DC supply to clean up one problem, but there are many other oriental wall warts elsewhere in the house, all creating hash. I have HF mobile and I can cruise the neighborhood and hear them as strong signals everywhere.
>    Nuff said.  73 Jim N4BE
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