Confused about pre-select filters and WIDE receive mode

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  • Updated 6 months ago
My goal is to be able to use a slice for ALE scanning, bypassing all filters so the rig is not engaging and disabling filters 2 to 5 times a second.

My understanding about filters is that when the slice is in WIDE mode, pre-select filters are disabled.  However, when I use MARS-ALE to scan frequencies, I still hear relays clacking as the frequency moves to different areas of the spectrum.  Note that I am scanning frequencies outside the ham bands.

Did I misunderstand how filtering works on the 6600?  Is this possibly an issue because I have the MARS filters installed?  Is there any way to simply bypass all filtering until the radio is put in transmit, then disengage the filters on receive?

If I 6600 will not work for this application, I have another question.  Is there a way to have the radio frequency set from external software ONLY when it goes into transmit?  The reason for asking this:  I can set up MARS-ALE to scan and receive via another SDR, but key the flex when an active frequency is found.  However, doing this currently will (obviously) transmit on whatever frequency the 6600 is set to, which does me no good.

Any thoughts and comments welcome.

73 - David, AG4F
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David Salomon

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Posted 6 months ago

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Al K0VM, Elmer

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Dave,
   The relay clatter your are hearing could also be Antenna selection relays if you have different Antenna selected pre frequency or they could be ATU relays if the slice is enabled for TX..  Or it could be that the slice is change from wide to narrow as you scan....  To do what you what and not the relays switching I would  think that you need to have all frequencies on the same antenna with TX not enabled on the slice ( or ATU in BYP on all frequencies ) .. I would set up a second non-scanning slice on the same SCU ( antenna)  on a frequency  that is not part of the scan ( 6meters ?)to insure that the SCU remains in WIDE on all frequencies.

Just some ideas !

   AL, K0VM
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David Salomon

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Al -

Thanks for the ideas.  Unfortunately, none of them apply/work here.  I'm using a single antenna and attempting to scan with TX disabled on that slice.  The antenna tuner is not enabled.  The slice does change from narrow to wide at some of the frequencies, i.e. MARS frequencies outside the ham band switch to wide.  However, even when scanning between several frequencies in the same general area of the spectrum, all of which use the wide mode, I still get relays clacking.

What I'd like to know is exactly what relays are being closed and opened?  Are they pre-selector relays, or something else?

73 - David, AG4F
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David Salomon

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One more comment...

I am able to use MARS-ALE to scan with my SDRs that do not have pre-selector filters.  MARS-ALE is also able to key the flex when it finds an active frequency and needs to respond.  What I'm missing is a way to change the frequency on the flex to the frequency on the SDR as soon as it is keyed.

If I could find a way to do that, I could just use one of my other SDRs as the receiver.

I tried using OmniRig, connecting the flex as one rig and the SDR as another.  It works fine with the flex, but I cannot get it to work with any other SDR.  I'm not sure why I'm having that issue.  I've tried numerous configurations, versions of OmniRig, etc., all to no avail.  If I can get this to work, I can write a very small program that interfaces with OmniRig, monitors the SDR, sees the switch to transmit, and changes the frequency on the flex.  I think that would work.

So close, and yet so far. :)
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Al K0VM, Elmer

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Dave,
  I don't have/use MARS/ALE but I did setup a channel scan in FRSTACK and am scanning 6 general coverages frequencies and have no relays clicking on my 6600.  
  All channels have same antennas selected for TX & RX.
  All channels have same preamp gain selected.
  All channels have ATU in BYP modes.
  All channels have TX non-enabled.
  I have a second slice 6m on same antenna (scu) as scanned channels ( this insures that the scanned channels are always in WIDE mode ).

Beyond that I would have to try running MARS-ALE to see what might be going on.

AL, K0VM 
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David Salomon

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Al -

I now think it has something to do with the MARS filters that are installed in my 6600M.  I did notice that when it scans with TX off (or switched to the other slice), that it doesn't switch the relays UNTIL the frequency it hits is inside or very near ham bands.

Perhaps the MARS filters are automatically disengaged when in a ham band, and re-engaged when outside a ham band.  If my theory is correct, then there is no way to accomplish what I want, unless Flex can come up with something I'm missing, or a way to keep the filters manually set to the MARS wideband filter.

You could prove my theory by installing either MARS-ALE or PC-ALE (the MARS version has transmit capabilities, but requires a license to do so), and trying it on your rig.  If the relays do not change inside or outside the ham bands, then I think it proves my point (because you will be doing exactly what I am doing, except for the MARS filter).  If you're up for it, I would be most grateful to know one way or the other.

Doh.

73 - David, AG4F
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Tim - W4TME, Customer Experience Manager

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The short answer is the relay clicks are not the preselectors if WIDE is always shown. The relay closures can be anything from the Nyquist filters, BCI filtering, TX final filters changing or the preamp settings changing.  You can't circumvent that behavior it is the logic that allows the radio to perform optimally.

Why do you want to stop this behavior?  Is it the noise?  If you are afraid of wearing out the relays, they are rater for a LOT of closures.  I did the calculation and if I remember correctly you would have to operate the radio doing ALE scanning 7x24x365 for close to 10 years.
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David Salomon

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Thanks, Tim.

It's not the noise.  I was worried about the relays given that I run MARS-ALE for about 14 hours a day most days.

I didn't realize there were so many other relays involved.

73 - David