6600M bandwidth center/width controls

Geoff_W8GNM

When the 6600M front panel filter controls are put into the "width / center" mode, the filter bandwidth collapses to zero bandwidth if the center frequency is moved toward the carrier frequency so that the one edge of the passband moves through the carrier frequency.
I believe the once the passband width is set, you should be able to move it around without it changing.   The controls work as expected in the "high / low" mode.

Rich McCabe

Wonder if your knob inner and outer ring is too close and turning both? Several guys have had issues.

Geoff_W8GNM

Rich, no the knobs are mechanically fine and work perfectly in "high/low" mode.
This problem only occurs in the "shift/width" operating mode entered by pressing the outer knob in to switch modes.  I think it is a software issue.

Rich McCabe

So is this in CW mode or another mode Geoff?  I assume you meant to say press the inner knob in to switch modes and not outer?

On phone it collapses the width when it gets to the carrier frequency and does not cross it.  You would think it would just stop.  I have never had a use for that filter mode in phone though.

Rich

Geoff_W8GNM

In SSB mode.  I haven't tested it in CW mode yet.  When I said outer I meant the one sticking further out  from the front panel.  You are right it is the inner, concentric, knob that changes the mode between "low/high" and "shift/width".

Rich McCabe

Geoff, you might be a good guy to explain to me why you would use this filter mode in SSB?  I find it frustrating that Flex does not associate the filter mode type with the mode.

 It seems to me that center is a method for tuning modes with a center carrier like CW and AM.

I would agree that it should not change the width when you hit center but don't understand why you would want to use this mode on SSB anyway.

Rich

Geoff_W8GNM

Rich, sometimes it is more convenient to set a receive bandwidth for SSB and then be able to slide this bandwidth window slightly up or down in frequency to eliminate QRM from above or below this frequency window without having to individually adjust the upper and lower frequency limits.

KC2QMA_John

Ted S

Geoff,

The filter widget in SSDR has the same annoying behavior. In SSB mode the filter cut next to the carrier can not be shifted past the carrier frequency. CW however works as expected. Someone made an assumption that since there is no SSB signal below the carrier the filter low cut should not extend below the carrier frequency. So the shift control widget mostly only shifts in one direction away from the carrier. You can shift it about a full 10k away from the carrier but not the other direction making the shift function mostly unusable for reducing high side QRM. You have to manipulate the high cut instead and end up changing the filter bandwidth. This doesn't effect performance, actually improving it by eliminating noise on the other side of the carrier, so one could argue that this is the right way to do it, but having to change filter bandwidth for high side QRM is not as convenient and defeats half the purpose of a shift control.

Another problem with the filter widget is that when you try to shift left or right, you almost invariably end up moving the mouse slightly up or down, the up/down motion also changes the filter bandwidth. Using the widget invariably leaves you with some random bandwidth setting that only approximates what you intended.

Compared to other radios It is a bit clumsy.

T.R. WR4T