At 19:21 17/03/2007, Tom Rauch wrote:
>How could we record the signal level, anyone know?
>
>73 Tom
I'm not sure how badly I want to display the gaps in my knowledge
about this problem to those on the list, Tom!
My feeling is that the least of the worries is automated recording of
signal strength; it's making sure that the signal strengths recorded
are unaffected by any factors other than the propagation mechanism
you're trying to observe, as you've already pointed out.
Unless I misunderstand your question, and am belaboring the obvious,
here's how I've recorded signal strengths for the better part of 10
years (a more detailed explanation is
at http://www3.telus.net/7dxr/333/333descr.html and in the
July-August 2001 QEX) I'll not claim great technical depth for the
article, and it dates back to the late 90s, but basically, somebody
writes a little program that tunes a computer controlled receiver or
transceiver through a serial port and reads the signal strength back
from the receiver, recording it in a file with a time stamp. I'm
sure it could be done in a more sophisticated fashion now (FFTs from
the output of a software defined radio for example), but this method
has recorded me the best part of a sunspot cycle's worth of data.
I've been surprised at how well Sprectrum Lab
(http://www.qsl.net/dl4yhf/spectra1.html) can give you relative
signal levels on a discrete frequency by using the strength of a
heterodyne on that received carrier, fed from your receiver's audio
output into a sound card (AGC off on the receiver of
course). Recording capability is included, you can "see" signals
you can't hear, and it's free.
best wishes,
Nick
VE7DXR
****************************************************************************
Nick Hall-Patch
Victoria, B.C.
Canada
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