Archive
A/C Upgrades
I’ve fallen behind on some updates here. We finally received approval to upgrade our air conditioning. HD transmitters create a boat-load of heat. As we have two of these beasts in one room it was time to convince corporate that we may want to protect our assets. We upgraded from 8-tons total air to 15-tons. We achieved the 15-tons by installing three 5-ton split units.
Our toughest assignment was to maintain a small footprint on the compressor units, so we had to propose a package unit which was refused by the landlord before we received the funds for the multi-unit installation. We purchased 3 Carrier units with vertical mount compressors. A rack was built to stack two high. So far we are running good.
The next step is to duct a bit to take care of air circulation.
I’ll fill you in on the other stuff soon.
Moseley SL9003Q AES Gotcha
What a week. AT&T takes down our T-1 STL without notice. An aerial to buried cut-over and their documentation is all screwed up. Sure enough, off the air! Then I discovered the hard way that when we switch to our aural STL the main transmitter, HTHD+, has no audio, yet the backup, HT-25, does!
What did I learn? The AES audio from the 9003Q has a “no audio” bit set in the output card. The Flexstar exciter reads it as no audio and thus no audio on the air. Huh? I receive a 3 year old tech sheet from Harris stating a modification to the Moseley output card. I perform the modification and now everything works. My question: Why did this output work fine with our original Flexstar exciter but not this one?
Earlier this year we had an actual failure of the XLR input board on the Flexstar. Exhibited the same no audio issue, but from both AES sources. This time I assumed the same thing. When I found out about this modification, I was floored. My predecessor did not document this? As I mentioned, we have used the auxiliary STL before without issue on the Flexstar. Or had we?
All I know now is that it is fixed and we are covered as we should. Making discoveries this way sure drives you nuts.
Moseley SL9003T1 Surprise
I had a rude awakening on Friday night/Saturday morning. No audio on air. I got them up on the backup STL and came on in. As we run T1’s for our main STL’s I suspected that our friends at AT&T had more issues with their infrastructure which is more common that not. When I entered the TOC I was shocked to see one of our Moseley SL9003T1 units dark. After all these years one of these beasts went bad? I checked the back and the power supply was registering one LED and the other was blinking erratically along with a weird clicking sound. Bad power supply.
I contacted the emergency tech and asked one very important question, “Can I use a power supply from a spare SL9003Q (aural STL) receiver?” The immediate, unwavering answer, “By all means.” Even the much older unit’s power supply was good to go. I traveled to the transmitter site and raided the power supply out of the spare unit and ran back to the studio. Dropped it in and we were back in business.
Though the old power supply looked less impressive that the new ones found in the T1 unit, it works like a champ. When Moseley is open I will order a replacement and a spare. Looks like it will not hurt to have on on the shelf.
And that is how my Fourth of July started! My Third of July was an air conditioning failure at the transmitter site.
BTW, I’m still working on updating the Equipment Notes page.
Harris HTHD+: More?
Yesterday we had our HTHD+ drop off the air again. When I arrived at the site the mimic panel showed an Exciter Fault!
1. Was it the Flexstar at fault?
Right now we are assuming, between us and tech support, that the PA module in the Flexstar is not happy with something. This is based on a fluctuating forward power of a few tens of a watt while the APC voltage remains constant. To troubleshoot this we await a new PA module for the exciter.
2. Did something else cause the exciter to fault?
What if the IPA is asking too much from the exciter? Seems to be stable and the fluctuations on its forward power follow that of the exciter, so it appears to be working fine.
3. What was the fault?
There is no indication nor have I found log files that would suggest what actually occurred. I need to research to see if the Flexstar keeps any log files. As it is an early “software controlled device” I suspect not or it is well hidden. A call may be in order.
On that note, when I powered up after tests it has remained on the air since. I will deal with the power fluctuations as long as I can maintain legality and on-air. We are a BTC/Navteq station. Believe it or not it is important for us to run HD. We will see if a new PA module actually works. If not, I will suggest a swap of the IPA.
Bored or Not Bored. That is the question.
Ah, Friday has come and about done. I had to attend a mandatory sexual harassment training seminar today. Required by this great state of CA.
So, this week was full of fun and excitement. Well, not really. Busy work and boredom. Well, not really boredom. I found out from DaySequerra that our M2.2R is still not ready to ship back. We stumbled on a real good issue. Can’t wait to hear about this fix. I messed with the Golden Eagle a bit. Darn firewall is blocking so no email notifications. Then again, why would I want that? Fix a VoxPro controller. First one in forever! Broken button cap.
I even replaced another XLR input board in our Flexstar. This was to replace the non-threaded one we originally received.
See, we can keep busy. I also spent time cleaning up the log that our Autopilot software prints out for one station. Made it fit on one page. Crazy the thing decided to stop working yesterday, too.
Other things to keep from getting bored: Do the stuff you hate or do not wish to do. Inventory! List all the little items that need to be addressed. UPS batteries. Clean the remote gear. The list goes on. Amazing what we can get done if you put your mind to it.
And the last thing to do: Work on a training schedule for your assistant. Always good to have some thing new to show the assistant. While he is off for a week I will look for some fine training items to do for him.
There you have it. The “what to do when you are bored” list. The number one thing: Clean the shop! BUT, make sure something is out so people do not figure out you are bored. 😉
Harris Visit
I had the pleasure of a visit from Mr. Geoffery Mendenhall of Harris Corp. the other day. We had a nice lunch and chat. We even visited the transmitter site to discuss the tube and life of these beasts in the HD world.
I have submitted the tube to Econco for an evaluation on how this tube fared. I will keep you posted on this. Our conversation focused on the fact that the failing tube caused IPA overloads. As the filament carbonizes we see a higher resistance and need more power to maintain emissions. Also we are thinking there is some increase in reactance withing the grid circuit. Somewhere a point is attained where the IPA cannot provide the necessary drive and overloads.
Once we have some evaluation on the state of the tube after removal we will not really know how far along or “burned out” the thing is. As the digital carriers require higher peak current, this tube in an analog transmitter would probably last a bit longer. All very interesting things.
Stay tuned for any other information that I may come across.
Equipment Notes and Comments
I see a lot of hits for this section. As mentioned in the previous Nautel post I will start placing links to my notes on the equipment I use and some notes on the conventions that I use.
If there is some specific item that I may have addressed and you would like to see notes on it, then please drop a comment or two and I will get to it.
Thanks for visiting and hopefully we will all learn more!
Nautel NV Software Update
Loaded in version 2.2 of the software. A nice jump from 1.3, eh? Anyways, the update rolled out as planned. Some cosmetic fixes and I noticed email notification is available. I will look into this and see how that works. I sure do like the connectivity aspect of new equipment.
In addition, I spend some time on the phone with Nautel and discussed the efficiency aspect of solid-state transmitters. I proceeded with doing some adjustments to improve the efficiency and I had some good results. I am going to write a tech sheet on the procedures I did. The bottom line is I raised the efficiency from 51% to 55/56% dropping the ambient temperature almost 4 degree Celsius. Stay tuned for this one! (if I’m lagging, please post a comment of this as a reminder.)
New Tube for the HTHD+
In the last couple of weeks I had an interesting series of events with the Harris HTHD+ transmitter. I was out there with my assistant a couple of weeks prior to these events and I made a comment that we should consider replacing the tube some time this year. Of course I was thinking conventional wisdom when it comes to tubes and I figured a couple of months before the actual replacement.
Well, the bottom line I was wrong. Here is the events that occurred. If you saw my tweet on Memorial Day, I experienced an IPA overload on the rig. I visited the site and checked everything. All looked good, even the readings. I had the transmitter back on in about an hour. I visited the site the following day to verify all readings and make sure I did not miss anything. All good again. I decided to purchase the tube and have it on site ready to go for a routine replacement.
Friday morning, 2:30am, I get the remote control call. The rig is off again. Off to the site and sure enough the IPA was indicating overload again. Well, I suspected that this soft tube may be the issue. As protocol, I called Harris tech support and discussed the situation. I had cleaned and checked all the internals for obvious issues. We both agreed that the tube could be the cause. Plus, for the HD rig we were pushing 2 1/2 years on the tube!
With luck, I tracked down our UPS delivery dude as he was making a delivery across the way. The tube was on board, so I signed for it and off to the site. Talk about timing. I performed the installation and tweaked the transmitter up. We were back in business. The end of last week I began my filament management and backed off a bit. All is still looking good.
We are coming up on two weeks after the first occurrence. After the tube replacement we have not experienced the IPA overload. In our case apparently a soft tube caused IPA overloads to occur. The story has been relayed to another in Harris. Interest has been piqued. I must note this is an early HDHT+ transmitter, so we may see some oddities. I intend to talk with Harris and compare notes.
Once again, do not rule out anything when tackling a problem. Eliminate the items not causing the issues and narrow it down to the specific item. In this case, the tube. Another learning experience completed.
Battery Backup
What does battery backup mean to you? As we go through this slow economy we are finding things that are on the list for maintenance which, if not dealt with soon, may jeopardize our operations. One of these items is our UPS (Uninterruptible Power Supply) system. I have two which are indicating battery replacement and these happen to be the ones in a control room that required cost cutting measures when built, so these are your off-the-shelf APC boxes. I cannot change the batteries while they are online, nor do I want to by-pass them and not protect my systems. Now I need to walk through and justify the cost of a decent UPS. In the “good” times I would be able to purchase these first and justify their existence when the bill arrived. This should be an easy walk-through as I think it is worth protecting $50k worth of equipment. It also protects our on-air product. We hate to be off the air, you know.
Of the routine maintenance you do this year, I suggest putting your money where it is necessary. Power protection should not be taken lightly. Though inconvenient to swap out the UPS, I know that in the future I will be able to change batteries without taking our studio off-line. With summer coming and our fine California weather which will require “rolling blackouts”, I want to be prepared. Even with a generator on the system, there is still transfer times and there will be brown-outs and spikes that do not trigger the system.
As it turns out, I found a way to change out one UPS without taking down the console or critical items. When the next UPS arrives I will take down the computers in the room. This is only a minor inconvenience as opposed to taking down the whole room. Invest in what you have, it may save you a bit of money down the road.
Tech Notes from the Field 