[Icom] IC-746 filter combinations.

[Brian Carling]

Wow, thanks Dana!

I really appreciate this.

It was a real chore installing this filter (not the physical part, but the "programming 
part.")

Now I hope I can figure it all out again. As I remember the manual was extremely 
deficient in explaining how to do it!

Thaks for your suggestions. WIll be good for a Saturday afternoon some time 
after I get the  new antenna up (or if it continues to rain like India here in Florida 
every day, he he!)

On 24 Sep 2002 at 16:42, Dana Hoggatt wrote:

> 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.
> 
> ----
> Your Moderator: Dick Flanagan W6OLD, icom-owner@mailman.qth.net
> Icom FAQ: http://www.qsl.net/icom/