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Zaxcom ERX firmware v2.0 - adds timecode calibration


Mark Orusa

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Reading time code on an LCD can be misleading.  Before I had a proper comparison tool I tried it and was less than satisfied with the results.

 In my tests I compared each component to a Denecke Master Generator which measures relative to its internal generator to within 1/100th of a frame.  I then noted the offset between the jamming device (GR2 when on the cart, and Nomad when in the bag).  Whether I originally tweaked the Nomad, or Zaxcom did, is therefore irrelevant to the test.

I measured all offsets at the beginning of each test, and at one hour intervals during it.

 

 

Edited by John Blankenship
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The new software has been tested and verified. Compairing the reader vs generator time code display on Nomad is not ever going to be exactly accurate as it is not a piece of test equipment. Time code offsets can only be compaired with a device that is made to show the difference between time code in 1/100 of a frame of less.

If there are any bugs in the new feature they will be quickly taken care of and an update will be available.

 

Glenn

 

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The bottom line, once calibrated, over a six hour period, time code seems to stay well within a half frame, or better, of the device it was calibrated to -- mostly better.

I've

 

Forgive me for asking an obvious question John, but I'm assuming that in these tests the ERX were set up with the IFB/Nomad Zaxnet but then left to run without the Zaxnet feed?
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No harm in asking.  

Yes, of course, as free-run time code stability is the whole purpose of the tests, I jammed via Zaxnet, then turned off Zaznet and made readings at the beginning and at each hour interval.

 

 

 

 

Magic. Good to hear that you've had better results than some folks. I'd be keen to see how they perform over a longer period.
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I did the test again, this time, It seems to give a better result.

1. I connected TC output with TC input on Nomad directly, 1 frame drift on display, 

2. Sync the TC from NOMAD via Zaxnet with 2 ERX2TCDs, and sync TC via Cable with Ambient Lock-it.

3. after 30min, turned off the Nomad, and switch the ERXs to another frequency.

4. after about 2 Hours, turned on the Nomad, connected all ERXs and Lock-it to TC Input on Nomad, take a photo with 1/400s shutter.

all devices are staying at 1 frame drift, I think this should be a good result. devices are keep running now, will see what happens after 10 hours, 

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I'm unaware of any properly conducted tests that show poor results with the new calibration feature.  If anyone is aware of any, please point them out, as that's something we all need to know, but I would caution others not to do a disservice to this community by spreading vague misinformation.  Shooting LCD screens does NOT constitute a properly conducted test.

If results vary we need to know it, but my guess is that, in this case, it's the tests that vary.

 

 

 

 

Edited by John Blankenship
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While the clock may be hardware, its timing accuracy can now be adjusted via a software calibration.

I don't know what ones-and-zeros magic Howy (Zaxcom's key programmer) has conjured up to implement this feature, what I do know is that, based on my beta testing, it seems to work quite well.

Edited by John Blankenship
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Does temperature come in to it?

If the chip starts cold and gets warmer during the day would that make any difference to the timing accuracy?

One calibration for the morning and another for later on?

Are temperature compensated chips more expensive?

Ambient say »Tiny Lockit« provides a rock solid, highly accurate, temperature compensating time code generator.

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Are you telling me you don't have a clause in your contracts that you'll only work under ideal conditions?

 

Which, by the way, is why I'm currently sueing dozens of production companies for their failure to provide only quiet locations. 

Oh, and for not having any fried egg left over by the time I arrive in the morning. 

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  • 1 month later...

Update:

I updated my erx's tonight. After 11 Minutes they calibrated (Ambient Lanc Logger into Fusion, from Fusion via IFB100 to the Erx'S). I did a test with turned off ifb 100 and one of the erx's pluged into the Lanc Logger directly. After one Hour there was a significant drift.(The Lanc Logger shows 1/100 Frame Drifts).

After this first test i calibrated the Erx's for 5 Hours and did the test again. There was a accaptable drift within 1 Hour(0.1 Frames). Then I recalibrated the Erx's manually in the right direction(based on the drift shown in the Lanc Logger) and turned off auto calibration.

Now I did the test again with both Erx's and had 0.00 drift within two hours!!!

 

Works like a charm.....

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Update:

I updated my erx's tonight. After 11 Minutes they calibrated (Ambient Lanc Logger into Fusion, from Fusion via IFB100 to the Erx'S). I did a test with turned off ifb 100 and one of the erx's pluged into the Lanc Logger directly. After one Hour there was a significant drift.(The Lanc Logger shows 1/100 Frame Drifts).

After this first test i calibrated the Erx's for 5 Hours and did the test again. There was a accaptable drift within 1 Hour(0.1 Frames). Then I recalibrated the Erx's manually in the right direction(based on the drift shown in the Lanc Logger) and turned off auto calibration.

Now I did the test again with both Erx's and had 0.00 drift within two hours!!!

 

Works like a charm.....

That's it. Finally. Thank you.

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Update:

I updated my erx's tonight. After 11 Minutes they calibrated (Ambient Lanc Logger into Fusion, from Fusion via IFB100 to the Erx'S). I did a test with turned off ifb 100 and one of the erx's pluged into the Lanc Logger directly. After one Hour there was a significant drift.(The Lanc Logger shows 1/100 Frame Drifts).

After this first test i calibrated the Erx's for 5 Hours and did the test again. There was a accaptable drift within 1 Hour(0.1 Frames). Then I recalibrated the Erx's manually in the right direction(based on the drift shown in the Lanc Logger) and turned off auto calibration.

Now I did the test again with both Erx's and had 0.00 drift within two hours!!!

 

Works like a charm.....

Wait, so you need other gear to properly calibrate the ERX? How does one 'calibrate the ERX manually in the right direction'?

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You only need Zaxnet to do the calibration.  See the earlier posts in this thread.  

I tested the new software with both a Nomad and also with a Deva being fed timecode from a Denecke master generator.  The results were impressively good in both cases.

BTW, the ERX version to currently be used is 2.01.

Right, but both yourself and Mr Bertolomi seem to have devices available with which to test the calibration accuracy. Lacking these, am I left with the option to hope for the best on calibration based on what I can see? I'm also unclear if calibrating the ERX is a one-time thing or if it needs to be done each time they are used.

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Right, but both yourself and Mr Bertolomi seem to have devices available with which to test the calibration accuracy. Lacking these, am I left with the option to hope for the best...

 

Keep in mind that having a master generator to test with isn't what calibrates the unit -- it's just a way to quantify the results.

My only issue with Bertolomi's post is that he stated, "After one Hour there was a significant drift.(The Lanc Logger shows 1/100 Frame Drifts)." which doesn't quantify what the drift was. In my earlier posts I offered actual findings whenever possible.

Some people think a few tenths drift is significant, whereas the camera itself can easily be a full frame off (based on where in the timecode "word" it grabbed its start point) with nary a squeak from post. (Research any of Marc Wileage's informed comments on sync in post for some worthwhile perspective.)  You don't need to have test equipment for this calibration to work -- and work well.

 ...

I'm also unclear if calibrating the ERX is a one-time thing or if it needs to be done each time they are used.

I thought this was thoroughly covered early in this thread, but in case it wasn't:

You can do it once and then turn off the recalibrate (don't quote me on what its called) while maintaining the calibration number. You have the option of leaving it on to recalibrate (10-12 min.) each time you power up. You can also enter your own number.

If all these options seem daunting, just turn on the feature, let it and your Nomad do its calibration thing, then turn off recalibration in the extended menu and live happily ever after, enjoying this unexpected new feature.

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Right, but both yourself and Mr Bertolomi seem to have devices available with which to test the calibration accuracy. Lacking these, am I left with the option to hope for the best on calibration based on what I can see? 

i would just do it the old way:

record a clap for a few seconds on both devices that you want to check for timecode synch, leave them running for a few hours, record a new clap every hour or so, import into your favourite TC capable editor, line up the files according to their time code and check the waveforms for sync.

chris

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