Archive
M2.2R by Daysequerra
I do not spend all my time breaking transmitters. I discovered a little problem with the Daysequerra M2.2R Modulation Monitor. At our transmitter site we could not get a decent read on anything. We observed up to 4 bars of RF on the level meter with ALL inputs terminated. Yes, that is correct, nothing but the power cord was plugged in. WTF, you would ask.
After describing the issue with the company, I tried all suggestions. I tried stuff like running on a UPS only. I even brought one unit back to the shop. That one worked a bit better in the shop, but I still had my doubts. I expected a couple of new boxes to try after I returned from vacation to find nothing. A quick email was shot off to Day.
I get a call which confirmed I was not going crazy and that Daysequerra was able to duplicate the problem. Looks like I found a little issue with the receiver board. In an high RF environment with many HD stations, the receivers were overly sensitive. I little issue that should be resolved here shortly and we will have some working boxes.
As always I do not fill you in on all the details until everything is complete resolved. I started to think I made a bad choice on purchasing these boxes though I have two working just fine at two other sites. If the fix works I will post and let you know if these do what I expect them to do: Modulation Monitor, SCA injection measurements, MPX output, and the other basics.
3/27/2009:
Just a note that I still await the repair on my monitors. The last I heard was the PCB manufacturer was behind on delivering the fix. Until the fix is tested I cannot comment on anything. I hate waiting.
10/2/2009:
I still wait for our box to come back with new guts. Can you say the longest service in the history of radio? Anyone else with a long repair tail? The last I heard our DOE talked at NAB about our specific box. No answer yet. Hello? Customer service, please.
All Is Well with Nautel NV20’s
Without getting into the details of version information as that is proprietary with Nautel, I will say we discovered a little issue with the controller on the NV20’s. Needless to say the issue did not cause much of an problem as more of an annoyance. It was a controller reset with no explanation. Random with no warning this reset would occur. I can say now that we worked this out as Nautel works on the next major release of NV software.
It is quite interesting to work through these issues and provide the information necessary to catch it and fix it. I feel good that we got it as quickly as we did. Tech support on Nautel’s side was awesome. If you find your NV series transmitter randomly dropping you off the air for 2 seconds and cannot find the explanation you better give Nautel a call. The fix is there. Get it.
I did drive our friends nuts as I was able to corrupt the AUI software on the transmitter itself. The fix was to ship me a new compact flash card with the “good” files in tact. Did the NV20 operate in this “mode”? You betcha. We had full remote control through the our remote control and we had full control via IP. If you are worried about such things as this with software based systems, you should be relieved to know that the important information is contained on the controller and does not fully rely on the computer running the AUI .
Great job Nautel. I look forward to the next major release so I can break that!
PS- Look forward to a Field Report coming to a trade near you.
Shunt Fed Skirts & Diplexing
The scenario: New 445′ tower, two AM stations diplexed, shunt fed.
Who thought of 445′ for stations on 1040 and 1240? Not a good beginning.
Three legs, each a climbing leg, one with a safety-climb cable.
Center feed to two sets of 3 skirt wires. That makes 6 skirt wires. Kintronics designs the skirts to go up each leg, that makes for 2 skirt wires per leg, and separated by approximately 36″. To me that is a bit too close for comfort. Lots of interaction.
Two storms now and each time the safety-climb cable comes loose from their clips. One time entangles 1240, the next it attacks 1040.
Repairs are made today and new clips are added to supplement the existing clips. The cable is run and looks good. Turn on 1240. It comes up OK. Turn on 1040 and it does not like what it sees. VSWR foldback and settles on low power. Engineer comes out and tries to tweak it. No go. I check the ATU’s and connections. All look good.
Conclusion: The cable was never installed properly and the impedance measurements and sweeps were not correct. 1040 needs to be tuned to make it work. Break out the bridge!
It is amazing what a “little” change will do to such a system. Shunt fed is fragile enough, but to put it on a tower at such an odd height is nuts. Then instead of having the skirts go up the face with some good physical separation, they are run up the legs. Now you cannot climb the tower without shutting it down. It will be interesting to see how far out of tune 1040 ended up. 1240 is slightly out as it was not happy after the connection checks on 1040. A mess it is.
Juggling the Fun
It is just crazy lately. I received a nice call today in regards to my comments on the Harris Flexstar. Thanks for that. I’m also busy with Nautel working out some little bugs with the NV20’s. These were to be expected as they are new products and will exhibit some strangeness. And that AM tower build, that is almost done though there are some details for the final city approval.
I am expecting my first software upgrade to the NV’s. This is necessary as we are experiencing an interesting little problem that may be commercial power related of which the NV’s are sensitive. Our Z10’s were also sensitive to something, but now it seems more apparent that a little phase brown-out situation may be occurring.
Overall I am quite please with the new transmitters, so these minor little things do not bother me. I feed information to Nautel and they are very receptive of the input. Daysequerra on the other hand….
Whomever decided that a shunt feed for an AM tower of odd-ball height is on drugs. Poor match that was closely matched shows signs of being unstable with some weather we are getting here. High VSWR that is random. A head-scratcher to say the least, but still annoying. It is a similar unstable thing our old tower exhibited in weather. Bad connections of the skirts? Poor design on how the skirts are installed. Rigidity of the skirts or lack thereof. Who knows.
All in all it is interesting, but very busy.
Cheers!
92kHz subcarriers and HD
Has anyone run into issues with 92kHz subcarriers and HD? Seems that when I turn on our HD carrier our 92kHz subcarrier client complains of noise or static. It is a crackly type sound from what I hear over the phone. It goes away when the HD carriers are off.
My initial feeling is the radios used to receive the subcarrier are sub-par and do not do well with the additional carriers turned on. We do not have that issue on another station with a 67kHz client.
As always I am interested in your thoughts and opinions. I will post any of my findings.
Harris Flexstar
And on the other side, we had to do some network modifications while we installed the HD for the Nautels and other two stations. The bottom line is we had to configure our switches to a managed mode and take down the HD data streams to do this. The Nautel gear came back without much issue when all was done. The Flexstar did not fair as well. As it was late in the day we decided to let the HD slide until today.
What did we find: This morning I was told to listen closely to the station. I confirmed an audible tone in the audio. Before heading to the site, I confirmed that the HD stream did not recover on its own. I was able to ping the exciter. Questions popped into my head. I can ping the box, so network connectivity was good, but no stream. Interesting. Once at the site I noticed the red LED on the Flexstar indicating that something was not right with the data. We switched to the backup transmitter and confirmed the tone went away. It did. The Flexstar had degraded to the point it was generating some sort of intermodulation tone.
I rebooted the Flexstar by cycling the power. After boot, it came up and all looked good. After placing it back on the air, the tone was gone and the analog audio was good again. Very interesting. As you may guess, I am going to send a note to Harris regarding this.
Nautel NV20 On The Air
We officially put the first NV20 on the air today, FM + HD. After cleaning up the air chain wiring we capitalized on the things we learned this week. It is amazing the engineering it takes to make a solid state transmitter run IBOC. Linearity is the key and on these boxes it is taken to an extreme. The mask is amazing.
I plan on having the second NV20 on by tomorrow afternoon. A slightly more complex chain and a bit more cleaning up. We will see how this goes.
And one question that may be in your head: yes, the exciter is brand new, built from the ground up. Bright and clean. Nice full bass. You may say it is transparent. Exciters should not color audio.
Nautel NV20 Update
I’ve been able to spend almost 2 quality days on these boxes. I have AES audio to each exciter and control is connected to the remote. I’ve done some basic tests into the dummy load. We still await AT&T’s repair of our data T-1, so no HD as of yet. I can rant about AT&T as it is over a month since the trouble ticket was called in.
As I am working without manuals, I have a list of items I need to discuss with Nautel, so they will not be written about until I have a proper understanding of the situation. On one box, I do seem to have a PM, power module, with a bad power supply. Not a surprise as I’ve seen other transmitters with modules that go bad within weeks of installation.
I do have an interesting situation with my Bird sample slug and the level to a Daysequerra modulation monitor. Either the slug is bad, and that means at least 2 are bad, or the mod monitor is bad. I do not seem to get any RF level on the monitor yet the meter shows full forward power and the spectrum analyzer shows the modulated carrier using the same sample. It’s just another thing to look at.
All in all, we are having fun doing this project, though it is taking a bit longer than expected.
Why Do I Bother?
It is days like today that I must ask myself, “Why do I bother?”
It wasn’t a bad start, it just went down hill quickly. It is tough to deal with an over reactive station. They heard a second long drop out on the air. They called me. I responded that I would check it out.
After listening for over 10 minutes, there was no audible issue. I reflected on what we have scheduled and new we had a T-1 with a trouble ticket open. AT&T is notorious for messing with other circuits that are at the same site as the one with the trouble. I informed the PD of my conclusion, but instead of listening, he proceeded to explain to me what they heard. All good and well, but I’ve heard the story. I just wanted them to LISTEN to my conclusion. They sure know how to talk, but when it comes to listening, I may as well be speaking to a wall.
That’s my rant for the day. Probably week. Why bother? Trying to help seems to be a waste. Instant gratification is more important. Oh well. I’ll get over it. I always do.
Nautel vs. Harris
I really do not want to get into such a “fight”, but our IT guy and my assistant mentioned how much better our Class A simulcast sounds compared to our Class B main station. This morning we took a trip to a spot where both stations come in real well, analog and HD. We listened to one. We changed to the other. Very interesting results.
The Class A station runs the Nautel V1-D with the M50 exciter and the Class B station runs a Harris HTHD+ with a Flexstar exciter. Both have the same processing. Both are fed the same way. The only difference is the transmitters. The Nautel does NOT color the audio in any way and the station sounds really good. The Harris colors the audio, it is slightly grungy, and it seems to be lacking in fullness and apparently “missing” sounds. It is quite interesting. We intend to record our results when time permits and everything settles down on the other work.
Anyone have similar experiences? Oh, we also noticed the HD’s sound different too. To us the Nautel is more listenable than the Harris. Crazy. An exciter and transmitter should not color the audio or degrade the audio in any way, shape, or form.
Tech Notes from the Field 