Nautel Extended Digital Mode

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Kelly
Posts: 500
Joined: Thu Aug 21, 2008 5:32 pm
Location: Washington D.C. Area

Nautel Extended Digital Mode

Post by Kelly » Mon Aug 20, 2018 7:18 pm

Just brought a brand new GV 7.5 on the air and it seems to be running in 'extended digital' mode. In other words the digital sidebands are wider to the inside than my Audemat Golden Eagle shows they should be. The Nautel AUI/GUI shows they are in the overall mask, but Nautel only brackets the mask to the outside, not the inside toward the analog carrier. According to the Ibquity HD Bible, that extra real estate is considered Extended Digital.

The original exciter that was brand new in the transmitter had a problem coming up 300kHz off frequency, so Nautel sent the current one as a replacement. I didn't set this station up, but I've been through the TX Importer and Exporters manuals stem to stern and can't see anything about changing between normal and extended modes. Any ideas?
Skype:kellyalford Twitter: @KellyAlford

kcbooboo
Posts: 518
Joined: Sat Dec 10, 2011 4:53 pm
Location: East of the Mississippi

Re: Nautel Extended Digital Mode

Post by kcbooboo » Tue Aug 21, 2018 5:34 am

I think the additional inward bandwidth is a function of the number of HD sub-channels you have and the sampling rate or quality you've chosen. I don't know what piece of the puzzle controls those (importer, exporter, something else). Since the digital carriers can't extend outward past +/- 200 kHz, if you have enough content to exceed about 100 kHz-worth of carriers they have to encroach upon the inner +/- 100 kHz, eventually displacing 93 kHz sub-carriers, then 76 kHz, then 57 kHz, etc.

Perhaps your previous HD setup didn't have the latest firmware to allow extended mode.

And by the way, you have a Golden Eagle that actually WORKS? Congratulations! You're lucky.

Bob M.

Kelly
Posts: 500
Joined: Thu Aug 21, 2008 5:32 pm
Location: Washington D.C. Area

Re: Nautel Extended Digital Mode

Post by Kelly » Tue Aug 21, 2018 7:46 am

kcbooboo wrote:
Tue Aug 21, 2018 5:34 am

And by the way, you have a Golden Eagle that actually WORKS? Congratulations! You're lucky.

Bob M.
Hi Bob, Yep believe it or not, the Golden Eagle at the studio seems to replicate what I'm seeing also at the TX. One has to reset it frequently, but it at least seems to be accurate.

Looks like a call to Nautel is in order. As a rule, I generally try to figure things like this out by myself, but I can't find anything about extended hybrid mode in the manuals. It must have something to do with re-mapping the bit rates.
Skype:kellyalford Twitter: @KellyAlford

djpcraze
Posts: 24
Joined: Tue Jan 14, 2014 10:14 pm
Location: Phoenix, AZ

Re: Nautel Extended Digital Mode

Post by djpcraze » Tue Aug 21, 2018 1:21 pm

Extended Digital would be set in the Importer actually... you are running in MP3 mode when you probably want to be running in MP1. The exgine doesn't care... it just spits out what is fed to it.

Unless you have specifically configured this, the extra bandwidth is also being wasted.

I run MP3 on one of my transmitters, and we cram our HD3 into the extra 26?ish kbps that "Extended Hybrid" provides (it doesn't combine with the other 96kbps, its an independent channel). That enabled us to keep passable audio quality for both our HD2 and HD3, while keeping the HD1 very high bandwidth and clean.

You can configure how your bandwidth is allocated with the web interface provided on the importer computer. It isn't exactly the most intuitive, but not too bad once you get the hang of it.

PS... I literally had no idea there was a manual/bible on HD. They sure as hell never gave it to me. I just passed my DRB and it wasn't from any book... it was via the school of "trial and error". I'm not sure even iBiquity understands half of how the system works.

Kelly
Posts: 500
Joined: Thu Aug 21, 2008 5:32 pm
Location: Washington D.C. Area

Re: Nautel Extended Digital Mode

Post by Kelly » Tue Aug 21, 2018 6:40 pm

Okay got it figured out with the direction from Terry at Nautel. I didn't have the "Multicast" manual at the studio for reference, but way in the back of the manual (which was up at the site) is a couple tables of the bit allocations depending on what mode(s) of HD you're doing. In our case, it was set up for something like: MP1_Even_Open. You have to stop all services, and then the drop down options are available. I changed it to MP1_Even (and one other parameter that I can't recall now), then restart the services Now my digital carriers are normal width and I got my RDS back.
Skype:kellyalford Twitter: @KellyAlford

fm-engineer
Posts: 23
Joined: Mon May 02, 2016 6:22 pm

Re: Nautel Extended Digital Mode

Post by fm-engineer » Sun Aug 26, 2018 7:24 pm

Interesting,

I've had my fair share of issues with a GV. Put a new GV10 on about two months ago. The main HD exciter would not make any RF right out of the crate, and that was just the start of issues. Backup non-HD exciter ran for a week or so until a new HD exciter arrived. Turned on HD service, and the multicast exporter would not stay synced with the exgine card in the exciter. After several exgine card swaps, Nautel sent an entire new multicast box. That fixed the issue partly, as we could stay in sync for up to two weeks, but that's as far as we can go before it loses sync. Also, just opening the multicast browser to look at the status of the exgine card will cause the exgine to go out of sync. When the multicast is out of sync, its impossible to keep the HD and analog audio time aligned, as they will continue to drift apart.
Kelly wrote:
Mon Aug 20, 2018 7:18 pm
Just brought a brand new GV 7.5 on the air and it seems to be running in 'extended digital' mode. In other words the digital sidebands are wider to the inside than my Audemat Golden Eagle shows they should be. The Nautel AUI/GUI shows they are in the overall mask, but Nautel only brackets the mask to the outside, not the inside toward the analog carrier. According to the Ibquity HD Bible, that extra real estate is considered Extended Digital.

The original exciter that was brand new in the transmitter had a problem coming up 300kHz off frequency, so Nautel sent the current one as a replacement. I didn't set this station up, but I've been through the TX Importer and Exporters manuals stem to stern and can't see anything about changing between normal and extended modes. Any ideas?

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