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Downgrading an AM radio station

WGHQ in Kingston, NY has been downgraded from a 5KW DA-1 to a 1KW non-DA system.  This was done because two of the three towers in the directional antenna array dated from 1960, were in very rough condition and needed to be replaced.  The remaining tower (furthest from the transmitter building) had been replaced in 1994, is in good condition and is being kept as the non-directional radiator.

Here are a few pictures:

WGHQ 3 tower directional antenna array, Port Ewen, NY

WGHQ 3 tower directional antenna array, Port Ewen, NY

More deferred maintenance

More deferred maintenance

RF and tower light feed disconnected from tower base

RF and tower light feed disconnected from tower base

Second tower base vegetation not as bad, tower disconnected

Second tower base vegetation not as bad, tower disconnected

WGHQ transmitter and original Collins phasing cabinet

WGHQ transmitter and original Collins phasing cabinet

First tower video (sorry, I appear to have no idea what I am doing with the camera):

Second tower video, this one is better:

Towers on the ground:

I made measurements on the third tower and constructed a temporary ATU with parts on hand to get the station back on the air. They are now running 1 KW day, 38 watts night, as per their CP. I will be going back up to finish the job once the brush has been removed from around the existing tower and the ATU building has been repaired.  The coverage with 1 KW is not bad, actually:

Predicted coverage map from FCC website

Predicted coverage map from FCC website

The translator is on its way.

The Ubiquiti Nano-Beam

I installed one of these wireless links between two transmitter buildings recently.  The Ubiquiti gear is not my first choice, however, the client insisted that we use this equipment likely because of its inexpensive nature (less than $65.00 per unit).  My overall impression is so-so.  They are fairly easy to set up; the AirOS is intuitive and easy to navigate around.  I had to upgrade the firmware, change the default user name and pass word, assign IP addresses, subnet mask, gateway information, SSIDs, security parameters, etc.  All of that was very easy to figure out.  My grip is this; it seems the hardware is a bit plastic-y (e.g. cheep).  I know some of the Ubiquiti models are better than others.  I hear good things about the airFiber units but they still don’t compare to the Cambium/Canopy gear.

For this installation, I used the shielded Ubiquiti “Tough Cable” with the shielded Ubiquiti RJ-45 connectors and Ubiquiti Ethernet Surge Protectors.  When making the Ethernet cables up, I made sure the shield drain wire was connected to the metal body on the RJ-45 connector.  I tested everything with my trusty Fluke Microscanner cable verifier which also shows continuity for the shield.  I am still not completely confident that the out door units will survive a lightning strike on the 898 foot (273.7 meter) guyed tower nearby.  Time will tell.

The system has a wireless path length of about 200 meters plus another 60 meters or so of Ethernet cable.  Latency when pinging the gateway across the entire network is about 3 to 4 ms (laptop>switch>nanobeam<->nanobeam>switch>gateway).  The network is being used for remote control/monitoring of a transmitters and backup audio via Comrex Bric link II IP CODECs.

screen shot; Nano Beam Air OS

screen shot; Nano Beam Air OS v7.2.2

On the plus side, the 802.11ac link is very fast; 650+ Mbps unwashed link speed is pretty impressive.  Strip off the wireless LAN headers and that likely translates to greater than 500 Mbps goodput.  Also, the inexpensive nature of these units means that we can keep a few spares on hand in case something does suffer catastrophic damage due to a storm.  The AirOS v.7 is pretty cool with the RF constellation and other useful tools like airView (spectrum analyser with water fall display), discover, ping, site survey, speed test, trace route and cable test.

After installing the updated firmware, which fixes a major security flaw with the web interface, the link was established with three mouse clicks.  After that, I ran speed tests back and forth for several minutes.  Basically, the speed on the LAN is reduced because of the 100 Mbps switch.  Even so, that should be more than enough to handle the traffic on this segment of the network.

The 16 channel bi-directional STL

As a part of our studio build out in Walton, we had to install a high capacity STL system between the studio and transmitter site. Basically, there are five radio stations associated with this studio and the satellite dish and receivers are going to be located at the transmitter site.

The audio over IP gear is getting really sophisticated and better yet, more reliable.  For this application, we are using a Cambium networks (Motorola Canopy) PTP-250 radio set and a pair of Wheatstone IP88 blades on either site.  Since there is quite a bit of networked gear at the transmitter site, the IP88’s will live on their own VLAN.  The PTP-250’s will pass spanning tree protocol, rapid spanning tree protocol, 802.1Q and other layer two traffic.

The Wheatsone IP88A blades are the heart of the system.  Not only do they pass 16 channels of audio, we can also pass 8 logic closures bi-directionally.  This is key because we are shipping satellite audio and contact closures back from the transmitter site.  The IP88A set up is fairly easy, once the IP address is entered.  The web GUI is used for the rest of the configurations including making the connections between units.

Pair of Wheatstone IP88A AoIP interfaces

Pair of Wheatstone IP88A AoIP interfaces

The switches are managed units.  The switchports need to be set up via command line to pass VLAN traffic.  There is an appendix in the IP88 manual that outlines how to do this with various manages switches.  This is the most important step for drop out free audio.  The switchports that connect to the two radios are set up as trunk ports using either VTP or 802.1Q.

Cambium PTP-250 5.8 GHz out door units

Cambium PTP-250 5.8 GHz out door units

The PTP-250 radios were already on hand, new in box.  They are built really well and look like they should not break in a year or so.  These particular units are connectorized, therefore an external antenna was needed.  There are many such antennas, this system ended up with a RF Engineering & Energy 5150-5850 MHz dual polarized parabolic dish with RADOMES.  RADOMES are necessary to prevent ice or snow build up in the winter.

RF Engineering & Energy 5150-5850 MHz dual polarized parabolic dish with LMR400 jumpers

RF Engineering & Energy 5150-5850 MHz dual polarized parabolic dish with LMR400 jumpers

STL link dish installed

STL link dish installed

1 1/2 inch EMT going from TOC to roof

1 1/2 inch EMT going from TOC to roof

Since the path is only 3.37 miles (5.43 kilometers), I set them up with a 40 MHz wide channel.  This is a rural, small town setting.  When I looked at the 5.8 GHz band on a spectrum analyser, it looks fairly uncongested.  These are MIMO single or dual payload selectable.  I will try them as single payload units, since the path is short and the band uncongested.  This should keep the throughput high.

Studio to transmitter site LAN extension

Studio to transmitter site LAN extension

The PTP-250’s use POE injectors in mounted in the rack rooms.  CAT5e shielded cable with the proper connectors properly applied is a must for lighting protection.  The PTP-250 units came with Cambium PTP-LPU lightning protectors.  I also installed Polyphaser AL-L8XM-MA type N surge suppressors on each RF port of each PTP-250.

Studio Buildout, Part II

Some pictures of the studio build out in progress.

Counter top mounted

Counter top mounted

This is the counter top, mounted on a riser with the wire way cut into it. These counter tops will have AudioArts Air4 consoles installed on them.

AudioArts Air4 console with microphones

AudioArts Air4 console with microphones

Studio is taking shape. Console mounted with microphones. The rack mounted equipment goes in the Middle Atlantic rack under the counter top to the left of the console.  That rack is on casters so it rolls out to get access to the back of the equipment.  We have pretty much done away with cart pods or other counter top equipment housings.  The automation and other computers will be mounted in the rack room and extended to the studio with IP KVM extenders.

Sub Panel with manual transfer switch

Sub Panel with manual transfer switch

We installed a small Square D sub panel and manual transfer switch. This is to prevent the “Space Heater” outages, you know, when the morning show guy plugs a space heater into the same circuit as the console or computer, trips the breaker, then calls you because they are off the air. Yeah, good times.

In addition, the manual transfer switch will allow them to use a good portable generator if there is a prolonged power outage. On the bottom of the switch I installed a 30 amp twist lock input receptacle.

Since the building is older, the grounding buss was installed and wired directly to the ground at the service entrance panel.   The building sub panel for this floor is using conduit for the ground conductor back to the service entrance panel, which used to be code compliant but no longer.

5.8 GHz dish with non-penetrating roof mount

5.8 GHz dish with non-penetrating roof mount

STL/LAN extension dish installed on roof top. I used an old non-penetrating roof mount for a four foot satellite dish.  The building owner was very specific about not having anything puncture the new rubber membrane roof.  Thus, the heavy rubber mats and sand bags instead of cinder blocks.  These stations will be using a Cambium PTP-250 system for STL/TSL and LAN extension. This will haul program audio for five radio stations plus satellite backhaul and remote control. It is a relatively short path with the FM tower visible from the roof top.

5.8 GHz path to FM tower

5.8 GHz path to FM tower

It was kind of hazy when I took this picture, but if you look really close, you can see the FM tower out there on the hill top.  The path is 3.37 miles (5.43 KM).  With a 40 MHz channel width, that should net about 175 Mbps bi-directionally, which is more than enough to do what we want.  This set up will require a pair of managed switches and some VLAN configuration, which I will post separately.

Studio Buildout, Part I

We are in the process of building a couple of new studios for one of our clients. This one involves a small market combo of one AM and four FM stations.  These stations were formerly located at one of the transmitter sites, two miles outside of town on top of a large hill.  That site could be difficult to get to during the winter and the building itself was not in the best of shape.  Thus, plans were made to move the studios to a better location.  Fortunately, we discovered that right in the village there are several suitable office buildings.

Any worthwhile project needs to be planned for.  The first consideration is the Studio to Transmitter Link (STL) paths.  Since this is a radio studio, it makes sense to located it where viable RF STL paths exist.  One might be surprised by the number times the issue of bad or non-existent RF STL paths has come up during these types of projects.

Studio to transmitter site LAN extension

Studio to transmitter site LAN extension

The next thing to check is the satellite path.  The plan right now is to keep the satellite dishes at the transmitter site, however, at some point in the future we can relocated the satellite dish to the roof of the studio building if desired.

AMC-8 satellite path

AMC-9 satellite path

The floor space was measured out and I drew out a floor plan:

Walton Studio floor plan

Walton Studio floor plan

Before we started work, all of the walls were painted and new carpeting installed.

Almost nothing at the old studio is worth keeping. Thus, all of the furniture, consoles, racks, STLs, and other equipment needed to be ordered.  A local kitchen company traded out the counter tops, which we picked up at their facility and delivered to the studio ourselves.

Studio counter top

Studio counter top

We will build risers for these on site then mount the consoles and such.

New Studio Equipment

New Studio Equipment

In the mean time, most of the new studio equipment has been ordered and delivered. There are still some outstanding items that have not arrived, but I am assured that those are in process and should be showing up shortly.

Used equipment racks

Used equipment racks

These equipment racks came from another market, but are in good shape.

I had a good meeting with the building owner regarding roof access, a sub panel for the racks and studios and other issues.

Emergency Communications

In this modern day and age, we take electronic communication for granted. Imagine being plunged into a world were there are no phones, cellphones, internet, email, television or even radio. Back in the day when I served aboard ships, we called that being underway.

Way, way back in the late 1980’s and early 1990’s, those that served at sea were at the mercy of the Fleet Post Office.  I will say, the FPO did a very good job routing the mail to the appropriate place, however, sometimes weeks or even a month would go by without mail.  When the mail finally did arrive, it all smelled the same.  Everyone’s wife or girl friend put some sort of scent on the outgoing, but since those letters mingled tightly packed in the same bag for weeks, often in hot humid tropical Pacific air, those scents blended together and became the Westpac Mail Smell, which permeated everything, even the letters from my father.

What will happen if people can’t sign on Facebook?

Fortune favors the prepared.

Communications loss in ordinary circumstances

Loss of utility company power, phone service and internet service can happen at any time for a variety of reasons.  The worst case scenario will occur when such loss is coupled with a natural disaster, which are often a major disruption of normal life.  Loss of information, especially at critical moments, can make a bad situation much worse.  In a situation where all normal means of communication are not functioning, something will fill that void, most likely the rumor mill.  That could be bad.

For information gathering, there are many options.  A good AM/FM shortwave radio is a decent start.  I would recommend a quality shortwave radio that has AM/USB/LSB options.  During run of the mill storms and power outages, many radio stations will remain on the air with emergency generators.  The key is to figure out which stations are staffed and offer good timely information.  NOAA all hazards radio can be good source of weather information, however, their transmitters can remain off the air for weeks or months at times.

One might ask “Isn’t this overkill or alarmist?”  I suppose that depends.  In the December 2007 ice storm, we had no power for seven days. In the aftermath of several major Northeast hurricanes and winter storms, some people had no power for more than two weeks.  Not only no power, but no cable, phone or internet either.  In situations like that, having some form of connection to the outside world can make a big difference.

Communications loss in less than ordinary situations

Other situations and scenarios may require more effort.  Prolonged information shortages could be triggered any number of national or global situations.  Shortwave receivers are not only for listening to international broadcast stations but also for tuning into the amateur radio (AKA “Ham”) frequencies as well.  Amateur radio is often used for emergency communications on a local and national and international level by governments and the Red Cross when other systems are out.  National and international communications are often heard on the HF band; 3-30 MHz.  The Amateur radio primary emergency voice nets are:

  • 3791.0 USB VOICE PRIMARY International, DX, and Emergency/Disaster Relief
  • 5371.5 USB EMERGENCY Emergency/Disaster Relief
  • 5403.5 USB EMERGENCY Emergency/Disaster Relief
  • 7185.5 USB VOICE PRIMARY International/Regional and Emergency/Disaster Relief
  • 14346.0 USB VOICE PRIMARY International/Regional and Emergency/Disaster Relief
  • 18117.5 USB VOICE PRIMARY International/Regional and Emergency/Disaster Relief
  • 21432.5 USB VOICE PRIMARY International/Regional and Emergency/Disaster Relief
  • 24932.0 USB VOICE PRIMARY International/Regional and Emergency/Disaster Relief
  • 28312.5 USB VOICE PRIMARY International/Regional and Emergency/Disaster Relief

These are voice channels from the ALE website. If there is not traffic on these frequencies, tune around a little bit.  In addition to voice nets, the amateurs also use something called ALE, which stands for automatic link establishment.  This is a data system that can be decoded on a listen only basis with a computer and some free software, for those so inclined.

For local amateur communications, 2 meter and 70 cm repeaters are often pressed into service.  For those, a VHF/UHF scanner is required.  Get a trunking scanner for 800 MHz police/fire dispatch as well.  Make sure that all radios can operate on 12 volts DC.  For this application, the size of the solar panel and battery is moderate, as receivers do not use much current.

Another option is a wide band USB radio for a lap top computer like a WinRadio WR-G315e.  These devices can be power by the USB outlet on the computer while the computer itself is charged with a solar panel.  For this route, some research on lap top solar chargers is needed.  The DC power requirements vary from lap top to lap top, so I can only offer general advice here.

With any receiver, a good antenna will greatly improve performance.  If there is room for an outdoor antenna, any length of wire strung up in a tree, away from power lines will work well.  For indoor setups, some type of receiving loop will work best.

Prolonged loss of communications in extraordinary circumstances

For longer term situations, gaining access to vital information and communications may become more problematic.  First of all, electronic communications require electricity.  Long term disruptions to the electrical distribution system could occur by either natural or man made events.  When those events happen, those that are prepared will be in a better position to survive if not thrive.  Things like ad hoc computer networks and amateur radio can facilitate two way communications.  In order to use amateur radio, one needs to get a license first.  This is a pretty easy thing to do and most other amateur radio operators won’t talk to you without a valid call sign.  Not only will they not talk to you, they will likely track you down and report you to the FCC.  That is the nature of the hobby, like it or don’t.

Amateur radio set ups can be very simple and not terribly expensive.  An used HF radio can be purchased on eBay for a moderate sum.  A simple multiband vertical antenna will serve general purposes.  For those that are interested in HF Link, a newer radio will work better.

Wireless ad hoc computer networks can be set up to establish a quasi internet over a moderate sized area.  WiFi WAN networks can be locally established using 900 MHz, 2.4 GHz, 5.8 GHz and 24 GHz license free channels.  Depending on the frequency, those links can be used for point to point medium to long haul links, or to establish local links to laptops and wireless devices:

  • 900 MHz: lower speed data rates, long haul, good to moderate building and vegetation penetration
  • 2.4 GHz: Limited channel availability, high atmospheric absorption, moderate speeds, low vegetation and building penetration
  • 5.8 GHz: High number of channels available, potential interference issue with TDWR radar systems, moderate to high speeds, line of sight only
  • 24 GHz: Large bandwidth, high speed, point to point back haul, line of sight only

Once the information is obtained, distribution to the greater public becomes a problem.  A very simple webserver (Apache, Nginx) with a light weight, simple index page containing vital information, news, weather, etc can be set up on a laptop and all HTTP traffic directed to the default index page.  This type of set up could be run off of a battery charged by a solar panel.  The issue here would be obtaining the information to put on the web page.

North Adams tower update III

And final.

It has been a year and a half since the tower collapse in North Adams, Massachusetts.  Since that time, WUPE-FM (Gamma Broadcasting), WNNI and W266AW (New England Public Radio) have been operating with STAs at lower than licensed power.   We have completed the installation of the combined antenna, filters and combiners and now all stations are back to full power.  Here are a few pictures of the transmitter room:

WUPE-FM and WNNI transmitter racks, North Adams, MA

WUPE-FM and WNNI transmitter racks, North Adams, MA

WUPE-FM (left hand rack) is using a Crown FM-2000 transmitter, loafing along at 1,060 watts. WNNI (right hand rack) is using a Gates Air Flexiva 2 running at 1,650 watts. Those stations are combined with a Shively Combiner:

Shively combiner

Shively 2 way star junction combiner

We are still doing some grounding and neatening work behind the racks:

Behind racks

Behind racks

The Shively versa tune antennas that were mounted to the wooden utility pole as emergency antennas will be retained as backup antennas for both stations.

Transmitters for WUPE, WNNI and W266AW

Transmitters for WUPE, WNNI and W266AW

We share the room with Access Plus, which is a wireless internet service provider in western Massachusetts. There stuff is in the open frame racks to the right of WNNI.

Another view:

Transmitter racks for WUPE-FM, WNNI and W266AW

Transmitter racks for WUPE-FM, WNNI and W266AW

TL;DR: Tower collaspes, facility is rebuilt better than before.

The Gates Air FAX-10

This is the first one of these transmitters that I have installed. This particular unit is analog only, but there is lots of room left over for an HD exciter, if need be.

GatesAir Flexiva FAX-10, 10.000 watt FM transmitter

GatesAir Flexiva FAX-10, 10.000 watt FM transmitter

The size of a 10 KW FM transmitter these days is pretty small, basically taking up the equivalent of one rack. This is a relatively small transmitter room, the old tube transmitter basically took up the entire room. With this unit, there is room to install a full power spare, if that was desired.

GatesAir Flexiva series RF modules.

GatesAir Flexiva series RF modules.

RF modules use LDMOSFET devices, each module has a power output of approximately 1,600 watts.

GatesAir Flexiva FAX10 power amp section

GatesAir Flexiva FAX10 power amp section

There are eight power amp modules and seven switching power supplies.

GatesAir FAX10 transmitter on the air

GatesAir FAX10 transmitter on the air

GatesAir FAX10 power output

GatesAir FAX10, licensed transmitter power output

One issue at this site, there is no reliable three phase power available.  There was a three phase open delta, but man, that thing scares me a little bit.  Since this is a single phase setup, I was curious to know what the current draw on each leg was at full power. I measured with my clamp on ammeter; 54.3 Amps at 120 volts, or 6516 watts per leg. Overall power draw 13,032 making the AC to RF efficiency 65.2%. VSWR calculates out to 1.21, which is not great.  I think the antenna could use a little bit of tuning love.

North Adams Tower update II

Work continues on rebuilding the North Adams tower after the collapse of March 2014.  Over last winter, a new tower was erected.  This is a fairly substantial tower.

New North Adams tower on ground

New North Adams tower on ground

North Adams new tower erected

North Adams new tower erected

In the interim, a new Shively 6810 four bay half wave spaced antenna was ordered. This antenna will be combined for two stations, WUPE-FM and WNNI using a Shively 2630-2-06 branched combiner. The 70 foot utility pole next to the building will be retained as backup facility for both stations. The Shively Antenna went up in stages.

New WUPE-FM and WNNI Shively 6810 antenna

New WUPE-FM and WNNI Shively 6810 antenna

Tower climbers rigging tower for new antenna

Tower climbers rigging tower for new antenna

Prescott Tower from Rutland Vermont was on site to do the tower work. They were the primary contractor for installing the new tower and did a really nice job of it.

New North Adams tower ice bridges to various shelters

New North Adams tower ice bridges to various shelters

Hanging the top two bays of new antenna

Hanging the top two bays of new antenna

Lift of bottom two bays and first tuning section

Lift of bottom two bays and first tuning section

Securing bottom section and bolting bays together

Securing bottom section and bolting bays together

After that, there was twenty feet of rigid line, another tuning section, then the 1 5/8 inch helax into the transmitter room. The antenna was tuned and the load looks very good. We are waiting for the electrician to finish wiring up the new racks and we will move both stations into their new home.

Installation Check Lists

On the subject of project management; often times, we need to keep track of the small details that can derail a project, blow the budget and upset schedules. A quick check list can help to identify things that might not have been planned for. I developed a checklist mentality in the military. There, we had checklists for everything. Simple day to day things like disposing of garbage over the side, or pumping the CHT (sewage) tank to complex evolutions like entering or leaving port all had a checklist.  On the aforementioned CHT tank; the Coast Guard cutter I was on had a vacuum flush system to conserve water.  Emptying the CHT tank involved a complex set of valve openings and closings to rout compressed air into the vacuum tank and literally blow the sewage overboard.  Anyone can see the danger in such a design.  Failure to follow the exact procedure resulted in raw sewage blowing out of the nearest toilets, which were unfortunately (or perhaps humorously) in the lower level officer’s staterooms.

But I digress.

I have made a series of outlines for different project types.  These can be used as general guidelines for project planning and management.  Of course, each project is different, but these are flexible enough that they can be adapted on a project by project basis.

These are for general use, and should be adapted for your own purposes.  Don’t forget to document and label all the wire runs, etc.

Also, do not forget the transmitter site maintenance checklists: FM transmitter site maintenance list, AM transmitter site maintenance list. I have used these reliably at many different sites since I committed them to writing in late 1999.

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

Free counters!