Re: Duo r preamp

Neil Smith G4DBN

Hi Neil, do you get *any* increase in the noise floor when you connect the antenna(s) for 17 and 10m.  If the noise floor rises more than a few dB then a premap isn't going to achieve anything other than reducing dynamic range.  If there is no change at all, or less than about 3dB, then it is worth looking at a preamp, although you need to do trhe test when the band is open and there are some signals (unless you are listening to Jupiter radio noise or meteorscatter).

If the noise floor does increase, but you can't hear it in the speaker, try changing the AGC threshold (not sure which menu does that on a DUOr sorry).

Finding a suitable preamp would be tricky, as you would need to ensure it could not be overloaded by out of band signals, so it would need good filtering and use a high-intercept device.  Not sure anything like that is avaialble commercially.  First step is to ensure that you definitely don't see any increase in noise when you connect an antenna when the band is open.

Neil G4DBN

On 23/10/2019 12:59, NEIL COLEY via Groups.Io wrote:
Preamp for 17 and 10mtr ssb please

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