I was talking to a friend from Russia about history, my job and various other things that are going on in my life. I received this reply, which I thought was interesting on a number of levels:
I’m glad we are on the same page about the era of the ‘cold war’. We were interested in your life even more than you in ours. We had almost no sources of information except for ‘The morning star’ which is a newspaper of the Communist party of Great Britain. The Voice of America and the Liberty (or Freedom, I have no clue because for us it was ‘RADIO SVOBODA’) were extremely hard to tune on. All foreign broadcasts were jammed. So to listen to the station you should maximize the volume up to the limit which was dangerous. Soviet houses are not at all soundproof and your neighbors could easily rat on you. Since that time I’d been dreaming of a small radio with could receive a clear signal from abroad. Of course we have the Internet broadcasting now but they often use old recording instead of live air and the signal depends on your data carrier. You should be online, you should have an app and unlimited data on your contract, your phone should be charged all the time. Too many conditions. Unfortunately a lot of foreign sites are banned here and the trend is to make this number bigger and bigger.
I find that perspective interesting. We take for granted our ability to listen to information and listen to different points of view, even those we don’t agree with. There are still trouble spots in the world and some people are not as fortunate. It is very easy to block internet traffic and there are several countries that currently block access to some or all of the internet, for the safety of their citizens, no doubt. Ideas are dangerous.
In the last ten to fifteen years, many large government shortwave broadcasters have reduced or eliminated their programming favoring an internet distribution model. This is a mistake. It is very difficult to successfully jam terrestrial radio broadcasts. Shortwave Facilities are expensive to develop and maintain, there is no doubt about that. However, as the Chief Engineer from Radio Australia (ABC) once told me “HF will get through when nothing else will.” Ironically, ABC has eliminated its HF service on January 31, 2017.
It seems to me that a sort of “Shortwave Lite” version of broadcasting might be the answer. Use more efficient transmitters with lower power levels closer in to the target areas. Such transmitters could be coupled to rotatable log periodic antennas to target several listening areas with one system, thus greatly reducing the number of towers and land required. Solid state transmitters with a power of 10-50 KW are much, much more efficient than their tube type brethren.
DRM30 (Digital Radio Mondiale) has not gained wide spread use in the MF and HF bands. Like it’s HD Radio counterpart, lack of receivers seems to be one of the adoption issues. As of 2017, there are only four DRM30 capable receivers for sale not counting software plug ins for various SDRs. That is a shame because my experience with DRM30 reception has been pretty good. I have used a WinRadio G303i with DRM plug in, which set me back $40.00 for the license key (hint for those nice folks at the DRM consortium; licensing fees tend quash widespread interest and adoption).
CFRX, Toronto coverage map, average HF propagation conditions
Finally, I have advocated before and still advocate for some type of domestic shortwave service. Right now, I am listening to CFRX Toronto on 6070 KHz. That station has a transmitter power output of 1 KW into a 117 degree tower (approximately 50 feet tall) using a modified Armstrong X1000B AM transmitter netting a 15-32 µV received signal strength some 300 miles away. That is a listenable signal, especially if there is no other source of information available. The average approximate coverage area for that station is 280,000 square miles (725,000 square kilometers). That is a fairly low overhead operation for a fairly large coverage area. Perhaps existing licensed shortwave broadcasters should be allowed to operate such facilities in a domestic service.
The point is, before we pull the plug on the last shortwave transmitter, we should carefully consider what we are giving up.
I have been tasked with installing one of these systems for a sixteen channel bi-directional STL. This system was first mentioned here: The 16 channel bi-directional STL system. As some of you pointed out, the unlicensed 5.8 GHz IP WLAN extension was the weak link in this system. It was not an interference issue, however, which was creating the problems. The problem was with layer two transparency in the TCP/IP stack. Something about those Cambium PTP-250s that the Wheatstone Blade hardware did not like and that created all sorts of noise issues in the audio. We installed the Wheatstone Edge Routers, which took care of the noise issue at the cost of latency. It was decided to go ahead and install a licensed link instead of the license free stuff as a permanent solution.
Thus, a Cambium PTP-820S point-to-point microwave system was purchased and licensed. The coordination and licensing took about three months to complete. We also had to make several changes to our network architecture to accommodate the new system. The PTP-820 series has a mast mounted radio head, which is the same as the PTP-250 gear. However, for the new system, we used three different ports on the radio to interface with our other equipment instead of the single port PTP-250 system. The first is the power port, which takes 48 VDC via a separate power cable instead of POE. Then there is the traffic port, which which uses Multi-Mode fiber. Finally, there is the management port, which is 1GB Ethernet and the only way to get into the web interface. The traffic port creates a completely transparent Ethernet bridge, thus eliminating all of the layer two problems previously encountered. We needed to install fiber tranceivers in the Cisco 2900 series switches and get those turned up by the IT wizards in the corporate IT department.
Andrew VHLP-2-11W 11 GHz microwave antenna
The radios mount directly to the back of the 24 inch 11 GHz Andrew antenna (VHLP2-11) with a UBR100 interface. The wave guide from the radios is a little bit deceptive looking, but I tried not to over think this too much. I was careful to use the O ring grease and conductive paste exactly where and when specified. In the end, it all seemed to be right.
Cambium PTP-820S mounted on Andrew antenna
Not wanting to waste time and money, I decided to do a back to back test in the conference room to make sure everything worked right and I had adequately familiarized myself with the ins and outs of the web interface on the Cambium PTP-820 radios. Once that was done, it was time to call the tower company.
Cambium PTP-820S on studio roof
One side of these are mounted on the studio building roof, which is a leased space. I posted RF warning signs around the antennas because the system ERP is 57.7 dBm, which translates to 590 watts at 11 GHz. I don’t want to fry anybody’s insides, that would be bad. The roof top installation involved pulling the MM fiber and power cable through a 1 1/4 inch EMT conduit to the roof. Some running back and forth, but not terrible work. I used the existing Ethernet cable for the management port. This will be left disconnected from the switch most of the time.
Cambium PTP-280S 11 GHz licensed microwave mounted on a skirted AM tower
The other side is mounted at about 85 feet AGL on a hot AM tower. I like the use of fiber here, even though the tower is skirted, the AM station runs 5,000 watts during the daytime. We made sure the power cables and Ethernet cables had lighting protectors at the top of the run near the dish and at the bottom of the tower as well as in the transmitter room rack. I know this tower gets struck by lightning often as it is the highest point around for miles.
PTP-820S RSL during aiming process
Aligning the two dishes was a degree of difficulty greater than the 5.8 GHz units. The path tolerances are very tight, so the dishes on each end needed to be adjusted in small increments until the best signal level was achieved. The tower crew was experienced with this and they started by panning the dish to the side until the first side lobe was found. This ensured that the dish was on the main lobe and we were not chasing our tails. In the end we achieved a -38 dBm RSL, the path predicted RSL was -36 dBm so close enough. This means the system has a 25 dB fade margin, which should be more than adequate. While were were aligning the transmitter site dish, a brief snow squall blew through causing a white out and the signal to drop by about 2 dB. It was kind of cool seeing this happen in real time, however, strangely enough, the tower crew was not impressed by this at all. Odd fellows, those are.
Currently brushing up on FCC part 101 rules, part C and H. It is always good to know the regulatory requirements of any system I am responsible for. As AOIP equipment becomes more main stream, I see many of these type installations happening for various clients.
This is the second Gates Air FAX-10 that I have installed. This one is in the shipping container transmitter site from the previous post of the same name. In this case, we dispensed with the equipment rack that came with the transmitter and installed it in a standard Middle Atlantic rack. The Harris rack configuration wastes a lot of space and since space is at a premium, we decided to do it our own way.
Gates Air FAX-10 in Middle Atlantic rack
The bottom of the rack has the transmission line dehydrator. The top of the rack has the Dielectric A60000 series 1 5/8 inch coax switch, a Tunwall TRC-1 switch controller and the Burk ARC-16 remote control. I cut the rack panel top to accommodate the coax switch. The racks were removed from an old studio site several years ago and were in storage since that time.
Gates Air FAX-10
The Gates Air FAX-10 transmitter on the air, running a sports-talk format.
Dummy load and Broadcast Electronics FM10B transmitter
View from the other side showing the test load and BE FM10-B transmitter. This transmitter had a problem that I have run into before with BE FM transmitters. The jumper between the exciter and IPA had the wrong phase rotation causing reflected power. I added a foot to it’s length and that problem disappeared.
For all you southerners and west coast people, we have been having an average winter here in the Northeast. While many of our transmitter sites are drive ups, we have several located at ski area mountain peaks. Technically, those mountain top transmitter sites are a fantastic way to get the Height Above Average Terrain (HAAT) way up there. Logistically, they are much more difficult to deal with. Installing a new transmitter or even refueling a generator takes major effort. Working in the cold and wind is much more fatiguing and requires paying special attention protective clothing, hydration, exposure, etc.
Here are a few pictures from Killington and Pico mountain ski areas in Vermont
Your ride is here.
The snow grooming machine is the only way to bring anything up to the top of the mountain during the winter time. In this case, I needed to replace a BW Broadcast TX 1500 watt transmitter.
Trail from ski lift to tower
Even with the snow grooming machine, the last few hundred yards needs to be walked. Fortunately, the snow is packed and not too deep here.
Tower on Pico Mountain
Tower is encrusted with ice. I can tell the tower climber is having a great day:
Tower climber working on ice encrusted tower
Riding the chair lift back down the mountain gets plenty of strange looks from those skiers coming up:
Pico chair lift
Over on Killington Peak, conditions are actually worse.
Killington Peak tower
The ERI antenna heaters cannot keep up with the ice buildup.
ERI two bay antenna with ice.
The general manager insists that this winter is not too bad and everything should be working right. My statement to her: Based on my 27 years experience, your shit is fucked up. But if you know how to fix this, come on up and show me. She deferred.
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 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, trouble shooting, 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.
Now where have I heard that before? I know that this is in the heart of Socialist Europe, but could this be what is in store here? I wonder how much longer the US radio stations will survive with shrinking revenue and lack of entertaining programming.
One bright spot; I have been thoroughly enjoying the unintentional humor of NPR’s (National Public, not Radio) “AHHHHH, TRUMP!” coverage. The Albany, NY outlet has really outdone themselves in this regard.
On a personal note; I have been feeling the urge to write more, so stay tuned!
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
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:
TELSTAR 12 (ORION 2)
TELSTAR 12 (ORION 2)
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 aluminium mesh dishes that were very popular in the 90’s 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 smart phone 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 a 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
Dish is 2°compliant? (Y/N)
Distance to receiver location:
Dish Azimuth (T):
Dish Azimuth (M)
Dish Height AGL:
(permanent or removable? Owned or not owned?)
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 simply 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 of 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 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 other composite device.
After studying the not always accurate schematic diagrams, the source of the problem seems to be 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 manufactures 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 mean time, 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 lots of documentation available on line. There are also several worth while plugins for scanning, trunking, decoding, etc. At a minimum, the SDR software should have a spectrum analyzer, water fall display and 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 water fall display for the PPM encoded stations:
WPDH using RTL 2832U and SDR Sharp
Not only can you see the water marking 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 crowed, 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 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:
C band Vertical beacon (MHz)
L band (LNB) Vertcial beacon (MHz)
For those in the continental United States, there is not much else past 139W, so AMC-8 will be the western most 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, 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.
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…
That season is here again; long practices, long drives to out of the way places, hotel rooms, cold arenas, and smelly locker rooms. Why do we do all this? Hopefully there is a life lesson in there somewhere. There will always be somebody faster, bigger, better with the puck, meaner, dirtier, etc. It is the competition that matters, teamwork may or may not overcome those obstacles. In the end, the reward will be equal to the effort put into it.
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
Those who would give up essential liberty to purchase a little temporary safety, deserve neither Liberty nor Safety.
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.
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.