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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