This is confusing marketing jargon. if Intercept Point Optimization (IPO) is on, this means that the preamp is off. You might not need to use the attenuator, but for the low bands I would at least recommend "IPO on", and save the preamp for 20 meters and higher frequencies. -- Lloyd, W3IUU
-----Original Message-----
>From: Michael Ryan <[log in to unmask]>
>Sent: Jun 22, 2011 8:38 AM
>To: [log in to unmask]
>Subject: Preamp
>
>Hi Lloyd:=20
>
>I'm not sure if the 450 has a preamp. Do you mean the IPO?=20
>So I should turn off the noise blanker, IPO off and Attenuator on?=20
>With the attenuator on though, the noise floor on the rig is vary low, =
>about 6DB I believe. =20
>
>73:=20
>
>Michael De VO1RYN=20