Jim Reid wrote:
> Using my Force 12 C3, 2 elements on 10 meters, I cannot
> repeat what Carl has reported; however, with my BigIR
> vertical tuned to 10 meters I can ! In order to hear a noise
> increase with the C3, I must have the preamp ON. I have
> the AGC threshold set fairly high 50 uV, as I assume that means
> no AGC action anywhere near the antenna input noise level,
> corrent? Or, should I have the threshold very low instead?
Orion's AGC doesn't influence the signal to noise ratio
significantly (which is very, veru good). It mostly
influences the perceived audio volume.
Therefore, the threshold value is not critical. Start from the
lowest value and increase it until the external noise volume
starts to decrease. Then use any value >= that one.
> Not sure if all the above says is that the vertical has a much
> higher noise level than the C3
Yes it does say so, although comparing antennas is not
the primary purpose of the test. It is intended to check
whether the receiver has the right sensitivity for
the circumstances (antenna, location, propagation),
or too much, or too little of it. It is all matter
of signal to noise ratio, which depends on receiver's
internal noise, not on "gain".
Please see my post from minutes ago for more details.
73,
Sinisa YT1NT, VA3TTN
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