WWB6/QLXD scanning

Jay Ashworth

Well-Known Member
Busiest week here in recent memory. I'll be needing to use all our wireless mics at the same time, and I mean *all* of them:

2 racks of 8 QLXD4 in G50 (534-598)
1 rack of 8 SLX4 in H19 (542-572)
1 rack of 2 ULXS4 in J1 (554-590)

And, well, I guess I've answered my question for me, but I'll ask it anyway, for Socrates:

Will receivers like the QLXD4 scan pass their rated bandpass, for building a WWB frequency map? How far?

And for my second rack of QLXD4, can I calculate and assign freqs to them even though they're not powered up right now? How do I push those later? Should I read the manual? :)
 
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Jay Ashworth

Well-Known Member
And backing the Scan Peak off to -55 and the Exclusion off to -75 gets me to here:

I suspect the fact that the receivers will be in different places will probably help a lot, and I expect WWB has a way for me to set that up, but I don't know what it is, so I'm going to push D9-D16 and come back to it during the week; I have til Friday or Saturday.
 

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Brenden Friedel

Active Member
Oh dear. Never had this much conflict...
Hey jay! That looks like some pretty rough conflicts. Although I do think this is a lot of mics in the same band you do have some room. It looks like you did a scan with all the mics (transmitters) turned on which is why you are experiencing all those conflicts. Let me know if turning off all the transmitters and rescanning fixes it.
 

Jay Ashworth

Well-Known Member
Hey jay! That looks like some pretty rough conflicts. Although I do think this is a lot of mics in the same band you do have some room. It looks like you did a scan with all the mics (transmitters) turned on which is why you are experiencing all those conflicts. Let me know if turning off all the transmitters and rescanning fixes it.
This was actually with only 8 of the QLXDs *powered on*, but starting Saturday, I'll need all 26 channels on in the same building. Those 8 on one side, and all the rest on the other side. Since that's true, I imported the entire 26 mics from inventory into the scan.

I have enough snake points on the other stage to split them up 8-8-2, but even though that should relax the intermod problems, I don't know how to tell WWB6 that there will be 30 ft or more between boxes. And that the box that's on now is about 90 ft and several walls from those 3...

I'm pretty sure it *can* be told, I just don't know how to do it.
 

Brenden Friedel

Active Member
This was actually with only 8 of the QLXDs *powered on*, but starting Saturday, I'll need all 26 channels on in the same building. Those 8 on one side, and all the rest on the other side. Since that's true, I imported the entire 26 mics from inventory into the scan.

I have enough snake points on the other stage to split them up 8-8-2, but even though that should relax the intermod problems, I don't know how to tell WWB6 that there will be 30 ft or more between boxes. And that the box that's on now is about 90 ft and several walls from those 3...

I'm pretty sure it *can* be told, I just don't know how to do it.
Did you try doing a rescan without any of the QLXD transmitters powered off?


You can also change the SLX and ULX to "more frequencies" in compatibility which should also allow you to configure more microphones in a tight band. This does increase your chances doe conflict but can work. I was able to configure all of these mics with a scan I had saved from my area.
 

Jay Ashworth

Well-Known Member
Did you try doing a rescan without any of the QLXD transmitters powered off?


You can also change the SLX and ULX to "more frequencies" in compatibility which should also allow you to configure more microphones in a tight band. This does increase your chances doe conflict but can work. I was able to configure all of these mics with a scan I had saved from my area.
At the moment, only the 8 QLXDs are installed. The other gear gets set up later this week, and of course, only the other 8 QLXDs can be pushed; we have to manually configure the other 10 units, Gr/Ch.

I was not expecting that it cared whether an inventory unit was powered on for these purposes; did I miss something?
 

Brenden Friedel

Active Member
At the moment, only the 8 QLXDs are installed. The other gear gets set up later this week, and of course, only the other 8 QLXDs can be pushed; we have to manually configure the other 10 units, Gr/Ch.

I was not expecting that it cared whether an inventory unit was powered on for these purposes; did I miss something?
it matters if the transmitters are powered on. The bodypacks and handhelds are transmitting frequencies waiting to be picked up by an antenna. As the receiver scans for frequencies in its spectrum, it's going to see those transmitters broadcasting their frequencies, and think it's a device it should avoid as it is over the threshold specified. (by default this threshold is -85dBm).

As for the other equipment, you can still configure those other 10 channels in WWB and since they are in the frequency scan range of the QLXD, you can use that scan data to find frequencies for those devices pre-install.
 

Jay Ashworth

Well-Known Member
Ok. I'm officially confused now.

WWB calculates avoidance based on two things, right? Things it sees in the scan, and *the freqs it assigns to mic channels*.

Since it has to do its work *before* it freqs a receiver *and you manually sync that to a transmitter*, it cannot be picking up other mics to avoid (reliably) from the scanning receiver; it has to do it based on its knowledge of the freqs it assigned for the receiver.

It must -- in order to be able to do its job -- be able to calculate both signal and intermod interference between all the radio chains it controls *without those chains being powered on*.

Right?
 

FMEng

Well-Known Member
Fight Leukemia
I suspect the SLX units contribute the most to the conflicts because they generate more intermod products and the receivers have, by far, the least selectivity. Just because they are in different channel groups doesn't mean the IM products don't slosh over into other groups. If all else fails, play with WWB by deleting SLX and adding QLXD or ULXD rental units.
 

Brenden Friedel

Active Member
Ok. I'm officially confused now.

WWB calculates avoidance based on two things, right? Things it sees in the scan, and *the freqs it assigns to mic channels*.

Since it has to do its work *before* it freqs a receiver *and you manually sync that to a transmitter*, it cannot be picking up other mics to avoid (reliably) from the scanning receiver; it has to do it based on its knowledge of the freqs it assigned for the receiver.

It must -- in order to be able to do its job -- be able to calculate both signal and intermod interference between all the radio chains it controls *without those chains being powered on*.

Right?
Hi Jay,

When you are doing a scan in a wireless workbench, you are essentially telling the receiver to become a scanner for its entire frequency range; in this case 534-598MHz.

Remove all of the current scan data you have for the QLX-D's and do a fresh scan following the instructions here. If you are still running into issues with intermodal after you do a fresh scan with 0 of the transmitters on, try configuring the SLX units as SLX_MasterList
 

Jay Ashworth

Well-Known Member
I suspect the SLX units contribute the most to the conflicts because they generate more intermod products and the receivers have, by far, the least selectivity. Just because they are in different channel groups doesn't mean the IM products don't slosh over into other groups. If all else fails, play with WWB by deleting SLX and adding QLXD or ULXD rental units.
So, lie to the inventory?

Is there in fact no way to tell it "this rack is 30ft away from that rack, which is 90ft away from that other rack"?

Or will that just not solve the problem?
 

Jay Ashworth

Well-Known Member
Hi Jay,

When you are doing a scan in a wireless workbench, you are essentially telling the receiver to become a scanner for its entire frequency range; in this case 534-598MHz.

Remove all of the current scan data you have for the QLX-D's and do a fresh scan following the instructions here. If you are still running into issues with intermodal after you do a fresh scan with 0 of the transmitters on, try configuring the SLX units as SLX_MasterList
I had in fact disabled all my old scans and started fresh; 2 scans with 3 receivers.

I had no packs powered on at the time, so anything it was unhappy about that wasn't a TV transmitter 5 miles from me was something it calculated. I'll rerun from those instructions tomorrow.
 

Brenden Friedel

Active Member
I had in fact disabled all my old scans and started fresh; 2 scans with 3 receivers.

I had no packs powered on at the time, so anything it was unhappy about that wasn't a TV transmitter 5 miles from me was something it calculated. I'll rerun from those instructions tomorrow.
Great. Can you attach your scan file whenever possible?
 

FMEng

Well-Known Member
Fight Leukemia
So, lie to the inventory?

Is there in fact no way to tell it "this rack is 30ft away from that rack, which is 90ft away from that other rack"?

Or will that just not solve the problem?
I don't think receiver spacing helps at all because the intermod products are generated by the transmitters. The analog systems are more prone to generating products than the digital ones, which is part of the reason why Shure says more QLXD and ULXD systems can work in a single 6 MHz TV channel.

The bottom line is that if WWB cannot find enough clean frequencies, you might have to ditch using the SLX systems together with the others. Replacing them with more, digital systems may allow the number of mics you need to work in the spectrum available. (That's why I mentioned renting.) Remember that spreading out mics among several, empty TV channel helped less capable systems, like SLX, work in moderate quantities. The TV repack took away many of those channels. Today, you might have to cram them all in one or two, 6 MHz chunks. And, the mic bands that had the most holes, when the mics were bought, might not be where the holes are post-repack. It all depends on how UHF TV cut the cards in your area, and how that fits with the channels your mic systems can tune to.

I'm a decent RF engineer, but not a wireless mic expert. Maybe the wireless mic gurus will chime in with some WWB tricks that I don't know.
 

Jay Ashworth

Well-Known Member
I'm going to be in early tomorrow, and I'll rebuild the inventory at 16 QLXDs, and 6 SLXs and see what I get.

I just need enough time to refreq the packs that are already deployed for a rental.
 

Jay Ashworth

Well-Known Member
Ok. I've trimmed the show file down to 16 QLXD and 6 SLX, and split things into 2 RF zones, to hopefully help tame the intermod problems, and we'll see what I get. If I still can't figure it out, I'll post a scan file in about a half hour or so. Dress isn't til tomorrow, so I've got a little bit o'time anyways.

Thanks for all the help so far, folks, and I promise I'll go RTFM next week.
 
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Jay Ashworth

Well-Known Member
And that did it. It successfully assigned freqs to all 16 Q's and 6 S's, with no warnings.

It deployed the freqs to the 8 Q's I have powered on right now, and I assume I can redeploy once the other 8 are set up without breaking the first 8?
 

themuzicman

Well-Known Member
Using IAS and TVDB data I was able to make the entire coordination work in a single zone without doing anything wacky.

The way I typically approach a coordination like this is to lay in the TV stations, then add the scan data to verify the FCC database, and then start with the least selective (SLX) to the next least-selective (ULXS4 in Master List Mode), and finally the most freely tunable (QLX-D).

As FMEng pointed out, zone spacing rack-to-rack doesn't matter in free-field as Intermod products are a result of spacing between transmitters and not on the receive side of things. Zones come in to play when you have physically separated rooms where the program will just be checking for direct 3rd order conflicts zone-to-zone and ignore 3tx3 and 5th Order Intermod products.
 

Jay Ashworth

Well-Known Member
... which is exactly what I have here. 8 of my Q's are on one side of the building, and the other eight along with 6 S's are on the other side of the building, roughly 80 or 90 feet apart, with at least three good solid walls in between. They're actually on different floors as well.
 

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