On 4/10/13 3:33 PM, Jeff Blaine wrote:
The noise I hear from it when sniffing is from the USB cable, not from
the GH unit specifically. I put ferrites on both ends of the USB just
as a precaution anyway.
The presence of a uP near the antenna does not necessary indicate
trouble. And a lot of those uP units will have a sleep state setting as
part of the hardware which is enabled by the firmware. So the device
wakes up when tickled by some input (like a RX flag) - or at a periodic
time interval. It really depends on the implementation for that unit.
The LDG does that, and frankly, it's a pain, because you have to
generate a "break" to wake it up.
Most modern micros run at a high enough clock rate that they just don't
have much output power at HF. We're long past the days of a 2MHz Z80 in
a S100 card cage putting birdies everywhere. VHF is another story.
DC/DC power supplies are another pain in the rear aspect because they
work at a few hundred kHz, and have copious output across the HF spectrum.
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