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Audio Freq Generator software for alignging rig?
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February 16th 05, 01:21 AM
AB7RU
Posts: n/a
Thanks Dave, good advice!
73
On Wed, 16 Feb 2005 00:59:13 -0000,
(Dave Platt)
wrote:
In article ,
AB7RU wrote:
The best I can suggest is that you generate the tone that you need
using the PC software you have, feed the line- or headphone-level
output from the PC sound card to an analog volume control (a 1k or 10k
audio-taper pot is probably a good choice), and use a reasonably well
calibrated oscilloscope or DVM to measure the resulting voltage and
trim it to 3 millivolts (P-P or RMS, depending on what the calibration
procedure asks for).
I'd recommend using a 'scope, to confirm that you're actually getting
a clean signal.
It's best to measure the actual signal level "in circuit", with the
PC/generator and the attenuator driving the rig's transmitter. If you
measure first and then attach to the rig, the rig's input impedance
may shift the level enough to perturb your calibration procedure.
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