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Nautel NV/NX firmware release

This is a Youtube video of the Nautel webinar regarding the NV and NX 4.0 firmware release.  I missed the original, live version due to other commitments.  For your viewing pleasure (55 minutes):

The upgrade seems a bit lengthy, but well worth it. Do not be scared away by Linux, which is a wonderful operating system. Once one understands some basic Linux commands, the operating system itself is very intuitive. I’d recommend anyone with interest in IT and networking to have a basic grasp of Linux and other open source software.

Well designed circuit boards

Sometimes it is the little things that catch the eye.  When I was installing a Nautel transmitter recently, I was admiring the circuit boards used for the transmitter controller.  I have seen a few circuit boards that are functional, but leave a little to be desired in the form department.  Does it really matter?  Perhaps not, but often times those tiny, almost insignificant details come back to bite you.  Little things like having the voltage regulator pins correctly placed or putting a toggle switch on the correct side of the board.  I have seen both mistakes from another, well known transmitter manufacturer.

Nautel NV controller board

Nautel NV controller board

Anyway, these are a few photographs of some well designed, well laid out circuit boards.

Controller board, NV transmitter

Controller board, NV transmitter

This is the main controller board.

NV controller board surface mount components

NV controller board surface mount components

Surface mount components.

NV controller board

NV controller board

Logic chips.

Nautel XR harmonic filter, part back part is the circuit board

Nautel XR harmonic filter, part back part is the circuit board

Part of the harmonic trap for the XR series transmitters.

It really is the little things that make big differences.  A circuit board under a cover that few people will ever see may seem like a very small and insignificant detail, but I notice and admire these things…

Moving and upgrading a translator

Something that I eluded to in a previous post, we finalized the move of the WSBS translator, W231AK, from the Fairview Hospital in Great Barrington to the side of the AM tower.

Tower crew hanging translator antenna on AM tower

Tower crew hanging translator antenna on AM tower

The move was started by hanging a new Shively 6812B antenna from the side of the AM tower, located off of US 7, north of Great Barrington. This is a half-wave spaced circularly polarized antenna.

While this work was going on, some guy from OSHA showed up and started taking pictures without asking permission or telling anyone who he was.  We informed him that he was on private property and asked him his reasons for being there.  He got in his car and left, no doubt to a parking lot down the road so he could keep the tower climbers safe… mostly from themselves… by levying huge fines for free climbing…  Wasn’t there something in the news about the government running out of money?  Anyway…

W231AK antenna, Great Barrington, MA

W231AK antenna, Great Barrington, MA

WSBS had been using this translator for a few years. The advantages for the station from the translator move are greater power output (from 35 watts to 250 watts ERP) and less operating expenses in the form of TELCO line charges and roof top rental at the Hospital.

WSBS tower with W231AK antenna mounted

WSBS tower with W231AK antenna mounted

In addition to that, the reliability of the translator should increase, as there have been several instances in the past when TELCO line problems have taken the translator off the air for days at a time.

W231AK new transmitter

W231AK new transmitter, WSBS base current meter below

The transmitter for W231AK was changed from a Crown 35 watt unit to a BW Broadcast T600.  These units are made in the UK and it is an all in one processor/exciter/transmitter. We took the cover off to make a few configuration changes and the entire unit is very well made.

BW Broadcast T600 insides

BW Broadcast T600 insides

One of the nice features of this particular transmitter is the screw down clamping method of connecting the RF devices. Lets face it, unsoldering MOSFETS is a PITA. This screw down clamp eliminates all that.

BW Broadcast T600 power amp

BW Broadcast T600 power amp

The audio input and processing board is pretty neat too.

BW Broadcast T600 audio input board

BW Broadcast T600 audio input board

There are several different processing settings which we played around with.  All in all, it seems like a pretty solid unit and I would recommend it to anyone looking for a low to moderate power transmitter.

Goodbye you piece of junk

We are scrapping several old transmitters these last few weeks as part of a site upgrade  A couple of Harris FM20 and 10H transmitters are out the door.

Harris FM20H transmitter, circa 1970

Harris FM20H transmitter, circa 1970

Some people like these transmitters. I am not one of those. I found that they were of dubious reliability, tended to drift out of tune and have AM noise problems, and had multiple catastrophic failure modes. If it was not tuned just right, it also had a tendency to have HF oscillations and internal arcing in the PA cabinet.

Harris FM20H3 PA cabinet modification

Harris FM20H3 PA cabinet modification

This transmitter had a non-factory authorized modification installed as a tuning aid.  Tune for best efficiency, minimum AM noise then check and see if it is arcing.  It is also advisable to wear hearing protection during the tuning process.

Harris FM20H3, circa 1972

Harris FM20H3, circa 1972

This particular transmitter was my nemesis for a couple of years. It is actually possible to hate an innanimate object, I can tell  you. Goodbye you piece of shit.

We tend to scrap these instead of dumpster them.  It saves the client a little bit of money on dumpster charges.  If all the metal is sorted out by category, e.g. all the copper windings are cut from the HV transformer and PS filter inductors, all the brass, aluminum, and wiring harness are separated, then it is almost worth the time and effort.  Personally, I’d rather see all that material reused than land filled.

Longevity

One of the stations that we do contract work for installed a Broadcast Electronics FM20T transmitter on June 6, 2001. It is still running on the original tube, a 4CX15,000A. By my calculations, that is 11 years, 7 months and 9 days, or 101,712 hours.

Broadcast Electronics FM20T transmitter

Broadcast Electronics FM20T transmitter

BE FM20T filament meter

BE FM20T filament meter

The hour meter shows 101,168 hours, which accounts for some maintenance, and other anomalies.  Overall, the transmitter has a 99.5% up time. I do not think the transmitter suffered any failures, rather, things like the generator and the STL failed instead.

EIMAC 4CX15000A tetrode

EIMAC 4CX15000A tetrode

Almost twelve years on one tube is pretty impressive.  I know that other Broadcast Electronics T model FM transmitters have similar tube life expectancies.  I wonder what the Broadcast Electronics secret is.

Zonecasting; the Technical Details

I saw this a item many weeks ago, however, had not had time to look at it until now.  Geo Broadcasting Solutions has filed Petition for Rule Making (RM-11659) based on a system divides the coverage area of major stations into smaller zones allowing for ad targeting of specific audiences.  They have coined the term “Zone Casting” to describe the scheme. It is covered by two US issued patents filed by Lazer Spots, LLC: 20120014370 and 20110065377.  After a look at these two patents, it seems there are three possible ways to accomplish this Zone Casting Scheme:

  1. In the first described method, the main transmitter is broadcasting area wide and all the zone transmitters are muted.  An inaudible signal is transmitted to all units, the main transmitter is then muted and the zone transmitters turn on and transmit localized content.  After the local information is transmitted, the zone transmitters mute and the main transmitter resumes broadcasting.
  2. In the second described method, the main transmitter and the zone transmitters are broadcasting area wide information.  The main transmitter ceases broadcasting area wide information and the zone transmitters begin broadcasting localized information.  At the end of the localized information the main transmitter and zone transmitters transmit area wide information.
  3. In the third describe method, the main transmitter and zone transmitters are broadcasting wide area information with “capture ratio pattern.”  The main transmitter initiates an alteration, temporarily becoming a zone transmitter.  The zone transmitters then transmit localized content.  After the localized content, the main transmitter becomes a main transmitter again.

All of the transmitters are linked to the studio via digital STL systems, content for the zone transmitters is distributed via IP network.  The transmitter frequencies are synced with GPS, similar to FM on channel booster stations.  Method number three includes possibly switching the transmitter output to a lower gain and or lower height antenna.

Zone Broadcasting Conceptual Diagram

Zone Broadcasting Conceptual Diagram

Of the three methods, the first system will result in the fewest interference issues.  No matter which method is used, there will be interference issues between the zone transmitters and or the main transmitter where the signal strengths are equal and the audio is 180 degrees out of phase.  These can be moved around slightly by adding delay to the audio signal, but they will always be present.  More about Same Frequency Networks (SFN) and Synchronized FM signals can be found here.  While the zone transmitters are transmitting dissimilar localized information, standard capture effect rules apply.

The system has had limited testing in Salt Lake City, Utah (KDUT) and Avon Park, Florida (WWOJ), which according to the filing and comments, went well.

Geo-Broadcasting is applying to conduct a full test with WRMF in Palm Beach, FL.  The expected installation will include up to 22 zone transmitters.

Conceptually, tightly targeted advertising is not a bad idea.  Advertisers like it because they perceive a better return for their dollar.  The cost of such a system is not insignificant. Transmitter site leases run $1-2K per month, leased data lines, equipment, installation work, equipment shelters, etc will likely run several hundred thousand dollars or more.

If it gets approved by the FCC, it will be interesting to see how it works and whether or not the system is financially justifiable.

 

The Nautel NV-5 Transmitter

We are currently installing this sweet little transmitter:

Nautel NV-5 FM transmitter

Nautel NV-5 FM transmitter

Like its big brother, the NV-40 at WVPS, the NV-5 is a very cool transmitter.  I am a born sceptic, things like a touch screen displays tend to make me a little nervous, especially on a transmitter connected to a 350 feet tall steel tower right next to the transmitter building.  That is the one major difference between WVPS and this site; at Mount Mansfield there are many things between the transmitter and antenna, this place, not so much.  Even so,  Nautel makes a good product, so troubles are not expected.

The ground strap, AC power, remote control and composite audio connections were all made with out difficulty.  Result, new transmitter on the air:

Nautel NV-5 FM transmitter GUI

Nautel NV-5 FM transmitter GUI

This unit is analog only, but the information on the spectral display is still useful.  The GUI uses Linux with a touch screen, which is a neat feature.

Nautel NV-5 FM transmitter controller board

Nautel NV-5 FM transmitter controller board

In case the front panel GUI goes out, all transmitter controls can be accessed via push buttons on the remote control interface, which is the small board to the right.  The main controller board is on the left.

Oh, damn: Una Parte

Guess what caught fire this time?  It’s this thing, which has become the newest piece in my burned up shit collection:

BE FM30A IPA regulator board

BE FM30A IPA regulator board

If you give up and are totally flummoxed, this is the IPA power supply regulator for a BE FM35A transmitter.  Here it is in better days, when it was actually working.  The IPAs are in pull out drawers on the right side of the transmitter cabinet, below the FX-30 exciter.

BE FM35A transmitter, on air

BE FM35A transmitter, on air

Said transmitter is aging not so gracefully, as it turns 26 this year.  There does seem to be a finite life to transmitting equipment, something that should be kept in mind when planning out next years capital expense budgets.  Regardless of all that, this event naturally occurred the day after Thanksgiving.

The good news, and there is always good news, we have many spare IPA regulators and PA modules in the shop ready to go.  Upon investigation, there were numerous other problems with this transmitter, which have been or will be addressed.

Restarting a Harris HT35 FM transmitter

This transmitter was retuned from 107.9 to 92.9 and put back into service. Retuning an HT35 transmitter is no small matter, there are 32 pages of retune instructions.  This unit is now in service as the main transmitter for WEZF, Burlington, VT.

The transmitter power output is 22,000 watts into a four bay, three around panel antenna, which gives it an ERP of 46,000 Watts at a height of 824 meters (2,703 feet) above average terrain. The tower is at the summit of Mt. Mansfield, which is 1,340 meters (4,395 feet) above sea level.

Mount Mansfield TV and FM antennas

Mount Mansfield TV and FM antennas

This is the Mt. Mansfield FM transmitter room. There are two TV stations in this building as well.

Final frames are of the WVPS Nautel NV-40 transmitter.

Australian Made Broadcast Equipment

Somebody working to preserve a record of past work:

Some of these have familiar looking cabinets and tube arrangements. They all look like classics to me and it is good that they are being saved. I noticed at the end of the video there is a Harris MW10A. As for the RCA Ampliphase transmitters; I maintained a BTA5J in Harrisburg PA on 580 KHz. It was reliable enough, but I could never keep it sounding good for more than a couple of days.

In any case, a worthwhile effort.  More information at: AWA Transmitters.

Axiom


A pessimist sees the glass as half empty. An optimist sees the glass as half full. The engineer sees the glass as twice the size it needs to be.

Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
~1st amendment to the United States Constitution

Any society that would give up a little liberty to gain a little security will deserve neither and lose both.
~Benjamin Franklin

The individual has always had to struggle to keep from being overwhelmed by the tribe. To be your own man is hard business. If you try it, you will be lonely often, and sometimes frightened. But no price is too high to pay for the privilege of owning yourself.
~Rudyard Kipling

Everyone has the right to freedom of opinion and expression; this right includes the freedom to hold opinions without interference and to seek, receive and impart information and ideas through any media and regardless of frontiers
~Universal Declaration Of Human Rights, Article 19

...radio was discovered, and not invented, and that these frequencies and principles were always in existence long before man was aware of them. Therefore, no one owns them. They are there as free as sunlight, which is a higher frequency form of the same energy.
~Alan Weiner

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