Shipping container transmitter site from the early 1990’s.
I do not particularly like these. I know, they are relatively inexpensive, easy to come by, easy to install, etc. However, a shipping container was not designed to house a transmitter, they have certain drawbacks. These are, in no particular order:
Air conditioning. Using a traditional Bard-type equipment shelter HVAC unit requires cutting through a lot of fairly heavy gauge steel. What’s more, the steel walls are uneven, requiring a filler.
They are by necessity, fairly narrow. Arranging racks and transmitters along the length of the unit restricts access to either the front or the back of the equipment. Meeting NEC clearance requirements for electrical panels, transfer switches, and disconnects can pose problems.
They are not very tall. Mounting overhead equipment can be problematic as one does not want to drill through the top of the container. Crosswise unistrut is one solution, but it lowers the overhead considerably.
Electrical work is slightly more dangerous. Doing any kind of electrical work, troubleshooting, repairs, etc is a little more nerve-racking when everywhere around you is a metal surface at ground potential.
They are difficult to insulate against cold and heat.
The door-latching mechanisms bind, wear out or otherwise fail over time.
All of those things being said, I am now rebuilding a transmitter site in one of these shipping containers.
Inside view of shipping container transmitter site
Fortunately, the original electrical work was not bad. The transmitter is a twenty-year-old BE FM10B, which will be retained as a backup. The new transmitter is a Gates Air FAX-10. We have installed several of these Gates Air transmitters in the last two years or so and they seem to be pretty solid units. This is the second 10KW unit I have installed.
Gatesair FAX-10 transmitter in Middle Atlantic Rack
We decided to install the FAX-10 in a Middle Atlantic rack since we did not have a whole bunch of extra room for a separate transmitter rack. The 1 5/8 inch coax switch is installed in the top of the transmitter rack along with a Tunwall TRC-1 switch control unit. The other rack will have the STL and all other ancillary gear. My idea is to have nothing in between the door and the FM10B so it can be easily removed when that day comes. Something, something about planning ahead since it will be likely myself removing the FM10B.
Westwood One, Premiere, Skyview Networks, et al. will be changing their satellite from AMC-8 at 139° W to AMC-18/SES-11 at 105° W longitude. More from AMC8transition.com. There are several considerations for this move:
Dish design and two-degree compliance
Obstacle clearance
Transponder frequencies
Timing
Two degree compliance is going to be an issue for many stations. Those old 2.4 and 2.8 meter mesh dishes are going to have issues with 105º West because that is a very crowed part of the sky. From New York, it looks something like this:
Satellite
Longitude
Inclination
Azimuth
Elevation
Distance
TELSTAR 12 (ORION 2)
109.21° W
0.491°
227.46°
31.09°
38596.91 km
TELSTAR 12 (ORION 2)
109.21° W
0.491°
227.46°
31.09°
38596.91 km
MSAT M1
107.72° W
7.430°
231.14°
38.16°
38011.55 km
ANIK G1
107.33° W
0.013°
225.25°
31.96°
38518.62 km
ANIK F1
107.31° W
0.020°
225.22°
31.95°
38513.76 km
ANIK F1R
107.28° W
0.052°
225.22°
32.02°
38510.37 km
ECHOSTAR 17
107.11° W
0.019°
225.01°
32.08°
38503.29 km
AMC-15
105.07° W
0.025°
222.76°
33.28°
38400.67 km
AMC-18
104.96° W
0.027°
222.64°
33.34°
38400.16 km
GOES 14
104.66° W
0.198°
222.21°
33.38°
38394.57 km
AMSC 1
103.44° W
9.810°
228.37°
43.31°
37616.42 km
SES-3
103.01° W
0.041°
220.41°
34.42°
38307.12 km
SPACEWAY 1
102.90° W
0.032°
220.25°
34.43°
38299.87 km
DIRECTV 10
102.82° W
0.017°
220.17°
34.51°
38292.86 km
DIRECTV 12
102.78° W
0.035°
220.12°
34.50°
38292.93 km
DIRECTV 15
102.71° W
0.009°
220.05°
34.56°
38290.50 km
SKYTERRA 1
101.30° W
3.488°
219.07°
36.33°
38131.32 km
DIRECTV 4S
101.19° W
0.011°
218.24°
35.35°
38228.26 km
DIRECTV 9S
101.15° W
0.014°
218.18°
35.36°
38228.57 km
SES-1
101.00° W
0.016°
218.02°
35.45°
38217.56 km
DIRECTV 8
100.87° W
0.036°
217.88°
35.54°
38211.02 km
Generally speaking, dishes need to be 3.7 meters (12.14 feet) or larger to meet the two-degree compliance specification. For many, this means replacing the current dish. This is especially true for those old 10-foot aluminum mesh dishes that were very popular in the 90s because of the TVRO satellite craze.
If the existing dish is acceptable, then the next issue may be obstacle clearance. Generally speaking, the 105-degree west slot (south of Denver) will be easier to see that the 139-degree west slot (south of Honolulu) for much of the United States. Still, there may be trees, buildings, hills, etc in the way. Site surveys can be made using online tools (dishpointer.com) or smartphone apps (dishalign (iOS) or dishaligner (Android)). I have found that I need to stand in front of the dish to get the best idea of any obstacles. While you are there, spray all the dish-holding hardware with penetrating oil like WD-40, Rostoff, or something similar. Most of these dishes have not moved since they were installed, many years or decades ago.
Transponder frequencies will not be the same, so when the dish is aligned to the new satellite, those frequencies will need to be changed. The network satellite provider will furnish this information when it becomes available. This generally requires navigating around various menu trees in the satellite receiver. Most are fairly intuitive, but it never hurts to be prepared.
The window of opportunity is from February 1, 2017 (first day of AMC-18) until June 30, 2017 (last day of AMC-8). Of course, in the northern parts of the country, it may not be possible to install a new dish in the middle of winter. It may also be very difficult to align an existing dish depending on how bad the winter is. Therefore, the planning process should begin now. A quick site evaluation should include the following:
Network Satellite Receive Location Evaluation
Satellite:
Satellite Location:
Dish is 2°compliant? (Y/N)
Distance to receiver location:
Dish Latitude:
Dish Longitude:
Dish Azimuth (T):
Dish Azimuth (M)
Dish Height AGL:
Dish Elevation:
Observed Obstacles:
(permanent or removable? Owned or not owned?)
Comments:
A .pdf version is available here. Based on that information, a decision can be made on whether or not to keep the old dish or install a new one. We service about 25 studio locations and I am already aware of three in need of dish replacement and two that have obstructive trees which will need to be cut. This work cannot start too soon.
I have been tasked with fixing one of these glorious contraptions. Aside from the usual Energy Onix quirks; design changes not reflected in the schematic diagram and a company that no longer exists, it seems to fairly simple machine. Unfortunately, it has spent its life in less-than-ideal operating conditions.
Energy Onix Pulsar 1000 in the wild. Excuse the potato-quality photo
Upon arrival, it was dead in the water. Found copious mouse droppings, dirt, and other detritus within and without the transmitter. Repaired the broken start/stop switches, fixed the RF drive detector, replaced the power supply capacitors, and now at least the unit runs. The problem now is the power control is unstable. The unit comes up at full power when it is first switched on, then it drops back to 40 watts, then after it warms up more goes to about 400 watts and the audio sounds distorted. This all points towards some type of thermal issue with one of the power control op-amps or another composite device.
After studying the not-always-accurate schematic diagrams, the source of the problem seems to be the carrier-level control circuit. This is based around a Fairchild RC4200AN (U10 on the Audio/PDM driver board) which is an analog multiplier chip. That chip sets the level of the PDM audio output which is fed into the PDM integrator circuit. Of course, that chip is no longer manufactured. I can order one from China on eBay and perhaps that will work out okay. This all brings to mind the life cycle of solid-state components. One problem with the new technology; most solid-state components have a short production life, especially things like multiplier chips. Transmitters are generally expected to last 15-20 years in primary service. Thus, transmitter manufacturers need to use chips that will not become obsolete (good luck with that), or purchase and maintain a large stock of spare parts.
In the meantime, the chip is on its way from China. Truth be told, this fellow would be better off with a new transmitter.
In my spare time (lol!) I have been fooling around with one of those RTL 2832U dongles and a bit of software. For those that don’t know, the RTL 2832U is a COFDM demodulator chip designed to work with a USB dongle. When coupled with an R 820T tuner a broadband RF receiver is created There are many very inexpensive versions of these devices available on Amazon, eBay, and other such places. The beauty of these things is that for around $12-30 and a bit of free software, one can have a very versatile 10 KHz to 1.7 GHz receiver. There are several good software packages for Windoze, Linux, and OSX.
The one I recommend for beginners is called SDR-Sharp or SDR#. It has a very easy learning curve and there is a lot of documentation available online. There are also several worthwhile plugins for scanning, trunking, decoding, etc. At a minimum, the SDR software should have a spectrum analyzer, waterfall display, and the ability to record audio and baseband PCM from the IF stage of the radio.
Some fun things to do; look at the output of my reverse registering smart (electric) meter (or my neighbor’s meter), ACARS data for the various aircraft flying overhead, a few trips through the EZPass toll lanes, some poking around on the VHF hi-band, etc. I also began to think of Broadcast Engineering applications and a surprising number of things came to mind:
Using the scanner to look for open 950 MHz STL frequencies
Inexpensive portable FM receiver with RDS output for radio stations
Inexpensive Radio Direction Finder with a directional antenna
Inexpensive Satellite Aiming tool
Using SDR sharp and a NooElec NESDR Mini+ dongle, I made several scans of the 945-952 STL band in a few of our markets. Using the scanner and frequency search plugin, the SDR software very quickly identified all of the in-use frequencies. One can also look at the frequency span in the spectrum analyzer, but this takes a lot of processing power. The scanner plugin makes this easier and can be automated.
Analog and digital 950 MHz STL frequencies, Albany, NY
I also listened to the analog STLs in FM Wideband mode. Several stations are injecting their RDS data at the studio. There is one that appears to be -1500 Hz off frequency. I’ll let them know.
Next, I have found it beneficial just to keep the dongle and a small antenna in my laptop bag. Setting up a new RDS subcarrier; with the dongle and SDR# one can quickly and easily check for errors. Tracking down one of those nasty pirates; a laptop with a directional antenna will make quick work.
Something that I found interesting is the waterfall display for the PPM-encoded stations:
WPDH using RTL 2832U and SDR Sharp
Not only can you see the watermarking on the main channel, you can also see the HD Radio carriers +/- 200 KHz from the carrier frequency. That is pretty much twice the bandwidth allotment for an FM station.
WDPA using RTL 2831U and SDR Sharp
Those two stations are simulcasting. WPDA is not using Nielson PPM nor HD Radio technology. There is all sorts of interesting information that can be gleaned from one of these units.
Aiming a satellite dish at AMC-8 can be a bit challenging. That part of the sky is pretty crowded, as it turns out. Dish pointer is a good general reference (www.dishpointer.com) and the Dish Align app for iOS works well. But for peaking a dish, the RTL 2832 dongle makes it easy to find the correct satellite and optimize the transponder polarization. Each satellite has Horizontal and Vertical beacons. These vary slightly in frequency, thus, but by tuning to the correct beacon frequency, you can be assured that you are on the right satellite. All of the radio network programming on AMC-8 is on vertically polarized transponders, therefore, the vertical beacons are of interest. Here are the vertical beacons for satellites in that part of the sky:
Satellite
Position
C band Vertical beacon (MHz)
L band (LNB) Vertical beacon (MHz)
Comment
AMC-8
139W
4199.5
949.25
AMC-7
137W
3700.5
1450.25
GOES15
135.4W
2209.086
N/A
NOAA WX
AMC-10
135W
4199.5
949.25
Galaxy 15
133W
4198
949.00
AMC-11
131W
4199.5
949.25
Galaxy 12
129W
3700.5
1450.25
For those in the continental United States, there is not much else past 139W, so AMC-8 will be the westernmost satellite your dish can see. Of course, this can be used in other parts of the world as well, with the correct information. Bringing a laptop or Windows tablet to the satellite dish might be easier than trying to drag a XDS satellite receiver out.
AMC8 vertical beacon output from LNB
In order to use the RTL-2832U, simply split the output of a powered LNB, and install a 20-30 dB pad in between the splitter and the dongle. Using the vertical beacon on 949.25 MHz, adjust for maximum signal.
For some other uses; look for the nearest and best NOAA Weather radio station. Several times the local NOAA weather station has been off the air for an extended period of time. Sometimes, another station can be found in the same forecast area. Heck, couple these things to a Raspberry Pi or Beaglebone black, and a really nifty EAS receiver is created for NOAA and broadcast FM. One that perhaps, can issue an alarm if the RSL drops below a certain threshold.
I am sure there are plenty of other uses that I am not thinking of right now…
