[Icom] IC-746 filter combinations.

[Dana Hoggatt]

On Sep 24,  5:25pm, "Brian Carling" wrote:
} Subject: [Icom] IC-746 filter combinations.
} 
} Say guys....
}
} I have the original type IC-746 with CW filter.
}
} Does anyone know if it's possile to set this rig up so
} it will transmit in USB mode and receive in CW mode?

I don't have my rig in front of me at the moment, but
I would guess that splitting your VFOs might do it.



} Or maybe to know how to set the thing to use the CW
} filter on receive while in the USB mode?

This one's covered in the FAQ.

------------------------------

Q:4.17	How do I configure the IC-746 to use a non-Icom filter?

	You have to lie to the rig.

	All of the IC-746 filter settings are on the basis of
	Icom part numbers.  (This is supposed to make things
	easier for new operators.)  Just tell the rig you've
	installed the Icom crystal that most closely matches
	the one you're actually using.

	Lying to the rig does have a side effect.

	The 746 cannot actually shift the IF filters' passbands.
	Instead, the 746 shifts the LO frequencies of the 2nd
	and 3rd IF stages to shift the signal back or forth,
	aligning the edge of the desired signal with the computed
	edge of the filter's passband.

	Small lies generate small effects, like when you
	tell the rig that a 2.1Khz wide filter is actually
	1.9Khz wide, yielding a 100hz offset in the control.
	Larger lies generate larger effects, like when you tell
	the rig that a 400hz filter is actually 2.4 Khz wide,
	yielding a 1,000hz offset in the PBT control.

------------------------------

Q:4.18	How do I use a CW filter in SSB mode to receive PSK31?

	Icom took their ease of use one step further, and
	programmed the rig to prevent the use of a CW filter
	while in SSB mode; probably to prevent what they
	considered to be a foolish user error.	They didn't know
	about PSK31 at that time.  So again, you lie to the rig
	during setup, telling it that the crystal is wider so
	that the rig will allow you to select it for SSB use.