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.
If you are the type of person that drives around to transmitter sites and steals things; fuck you. You have no idea the problems you are causing to get a few extra dollars worth of scrap copper.
Missing copper ground buss bar
I have a feeling that most of these copper thefts can be attributed to out of town tower contractors removing old cellular equipment from towers. Notice, only the buss bar and copper ground wire is missing. They did not try to cut the transmission lines. In other words, they seemed to know what they were doing. I have noticed around here that a when a particular contractor, employed by an unnamed large company that rhymes with glint, would work at a site, things would be missing afterwards.
Perhaps it is just a coincidence. I have never been able to catch anyone pinching things. However, if this is you, and I catch you, you can rest assured that I will block you in with my car, then walk down the road and call the police.
I have put off writing anything about this for several reasons. First of all, there is a lot of secrecy surrounding the use of the Voltair magic machine. No one will admit to it, however, I have had several off the record conversations with various engineers. All of this is hush-hush, unofficially off the record and on the QT, so no names, call letters or cities of license can be disclosed.
The general gist of these conversations is this; the Voltair seems to be increasing ratings in some cases and but not others. It is sometimes too early to tell whether the increased ratings are a one time anomaly or something more permanent. In one case, an AC station saw 30% increase in numbers, while a certain talk station saw next to nothing. Results are mixed.
In the credit where credit is due department; the Telos Marketing campaign is has been effective. Again, from a variety of different sources; Program Directors, Market Managers and Sales Managers are “beside themselves,” or “giddy” when the UPS truck delivers the Voltair to the front door. In one case, requiring that “I (the market engineer) drop everything” to get it installed as quickly as possible and “acting like it is God’s gift to radio.” It looks like all those trade publication ads are paying off, $15,000 at a time.
Voltair PPM encoder enhancing device, in the wild
One interesting thing about the Voltair, you can program simulated listening environments such as sporting events, restaurants, kitchens, vehicles, etc. This allows the user to see how their program material is being decoded by a PPM survey device in those types of environments. For example, if you are a sports station, having your program material decode well at sporting events or restaurants and bars might be important.
Of course, we have all seen the confidence display:
Voltair PPM encoder enhancer “confidence display”
So, what does this mean? Perhaps there is an inherent flaw in the Nielsen PPM encoding technology? In the past, PPM has been blamed for the demise of the Smooth Jazz format. I always had the notion that Smooth Jazz was responsible for the demise of the Smooth Jazz format. However, if PPM is indeed causing certain program material to disappear from the airwaves, then it would be a case of the tail wagging the dog. If PPM requires that station owner’s purchase a $15,000 in order to get credit for their TSL and cume, then there is a pretty big problem with the technical aspects of the system.
Of course, there are others that say there is no “Voltair effect.” The Voltair machine is simply a fancy and expensive gizmo that looks good but does not really do anything.
Nielson Audio is having a Webinar on July 21 to address some of the questions regarding the Voltair and PPM encoding for subscribers only. It will be interesting to see what the outcome is.
Excerpt of a memo from a few years ago, during the great recession:
(Redacted) has implemented a consumables reduction program. All consumables; copy paper, toner, note pads, pens, pencils, paper towels, garbage bags, paper plates, plastic flatware, toilet paper, and so forth must be reduced by 25%. (Redacted) is spending far to much on such material which is impacting our financial performance.
My contribution to the effort:
new consumable reduction program
I wouldn’t want the CEO to miss his bonus this year…
Every year, the Maritime Radio Historical Societycelebrates the closing of the last commercial Morse code radio station, which happened at 0001 UTC, July 13, 1999. They do this by re-manning the watch for a few hours in honor of all those who so diligently listened for distress signals on 500 KHz and other frequencies continuously for over 90 years. Your humbleauthor was one of those, who in the late 1980’s and early 1990’s strained to hear, through the static crashes and OTHR, the simple, yet effective combination of SOS sent in Morse code.
Fortunately, after the closure of KPH, the National Parks Service took over the land and preserved the buildings and antenna fields intact. Today, a dedicated group of volunteers maintain these facilities as a working museum. This is the earliest history of radio technology and from this, sprang Amateur Radio, then Broadcast Radio services.
So, if you have the opportunity on July 12 (Sunday, starting at 8 pm, EDT), tune around to some of the frequencies listed below and see how ship to shore communications was handled:
425, 454, 468,480,512
These are duplex frequencies, meaning; the ship transmits on one frequency and listens on to the shore station on another and vice versa.
Those medium frequencies do not carry that far during daylight, however the high frequencies should be heard across the world.
In addition to that, there are youtube videos to watch:
There are more videos on youtube, if one is so inclined.
Those old RCA transmitter look like they are in excellent condition. Somebody has spent a lot of time restoring those units.
Hopefully, one of these years, I will get a chance to head out to San Fransisco during the middle of July and see this in person. It would be nice for my children to see what their old man used to do in what seems like a different lifetime.
Hurricane season is here. This time of year makes me fondly remember hurricanes of the past and the things we had to do to get stations back on the air; walking a mile down a sandy spit of land, wading through swamp water to get to the transmitter shack, being threatened with arrest by the Connecticut National Guard, blow drying RF modules with a hair dryer, sleeping in a camper for a week… Ahhhh, good times, great times!
The one thing that I did learn, if the disaster is big enough, expect none of the normal services to be functioning. That includes things like gas stations, fuel delivery, grocery stores, restaurants, hotels, UPS, roads, bridges, telephone service, internet service, etc.
It is not a far fetched scenario for the main FM transmitter site to be out of commission and will not be available or accessible for some prolonged period of time. There might also be mitigating circumstances such as catastrophic tower failure, destruction of transmitter building, flooding, or other major infrastructure disruptions. In those situations, calling the broadcast supply vendor of choice for a replacement might not be an option.
It has happened before…
All of these things got me to thinking about how to fabricate a reliable FM broadcast antenna from simple materials available on hand. The FCC allows for temporary operation with an emergency antenna in part 73.1680, which reads:
(a) An emergency antenna is one that is erected for temporary use after the authorized main and auxiliary antennas are damaged and cannot be used.
(b) Prior authority from the FCC is not required by licensees and permittees to erect and commence operations using an emergency antenna to restore program service to the public. However, an informal letter request to continue operation with the emergency antenna must be made within 24 hours to the FCC in Washington, DC, Attention: Audio Division (radio) or Video Division (television), Media Bureau, within 24 hours after commencement of its use. The request is to include a description of the damage to the authorized antenna, a description of the emergency antenna, and the station operating power with the emergency antenna.
(1) AM stations. AM stations may use a horizontal or vertical wire or a nondirectional vertical element of a directional antenna as an emergency antenna. AM stations using an emergency nondirectional antenna or a horizontal or vertical wire pursuant to this section, in lieu or authorized directional facilities, shall operate with power reduced to 25% or less of the nominal licensed power, or, a higher power, not exceeding licensed power, while insuring that the radiated filed strength does not exceed that authorized in any given azimuth for the corresponding hours of directional operation.
(2) FM, TV and Class A TV stations. FM, TV and Class A TV stations may erect any suitable radiator, or use operable sections of the authorized antenna(s) as an emergency antenna.
(c) The FCC may prescribe the output power, radiation limits, or other operating conditions when using an emergency antenna, and emergency antenna authorizations may be modified or terminated in the event harmful interference is caused to other stations or services by the use of an emergency antenna.
In this situation, making a circularly polarized antenna would be overly complicated, so either a horizontally or vertically polarized antenna would be the most likely scenario. There are a few antenna types that readily lend themselves to field expedient fabrication.
Of these, the 1/2 wave wire dipole is the easiest to construct. Cut two wires, length (in feet) determined by the formula 234/Frequency (Mhz). Attach one wire to the center conductor and one to the shield, stretch to the wires out and tune for minimum SWR by cutting or adding small lengths to the ends. The total length for such an antenna would be approximately five feet and it could be mounted horizontally or vertically. The issue with a wire dipole would be bandwidth and power handling capability.
A 1/2 wave dipole made from tubing would have better bandwidth and power handling, but tubing is a little harder to work with when it comes to tuning the antenna.
Frankly, if one is going to go through the trouble of using tubing to create an emergency antenna, the the J-Pole (end fed antenna with a 1/4 wave matching section) is probably the best. This antenna is easier to tune, does not need to work against a ground plain, has good bandwidth and a low take off angle, meaning more power is radiated out toward the horizon, giving it a good deal of gain over both a ground plane or dipole antenna. Additionally, when using standard RG-8, RG-214, LMR-400 or other similar transmission line, a well matched antenna might be able to accept about 1 KW of input power, which would net approximately 4.4 KW ERP. Not an insignificant sum, especially in an emergency situation.
Vertical radiation pattern for J-pole (1/2 wave end fed) antenna
1/4 wave ground plane vertical radiation pattern
There are many J-Pole antenna calculators available on line, but many of them include a 20 inch or so section of tubing below the tuning stub that can be electrically coupled to the supporting structure. This configuration defeats the main advantage of the antenna, creating a good deal of upward radiation. It is a better idea to use a non-conductive support piece and keep any conductive materials at least 1/2 wave length or greater from the radiating portion of the antenna.
The basic j-pole antenna looks like this:
J Pole (1/2 wave vertical antenna) diagram
The radiating part of the antenna starts above the tuning stub. Basically, the 1/4 wave stub is shorted at the bottom, the feed point is adjusted away from the shorted end until a 50 ohm impedance point is found. The center conductor of the coax is attached to the 3/4 wavelength section, while the shield is connected to the stub. The critical distances are the tuning stub length and the distance of the feed point from the shorting section. I created an excel spreadsheet (.xls) that can be used to create all the lengths required to fabricate one of these antennas. That spreadsheet can be had here: J Pole Calculator
Having a few moments of time to spare, I thought it would be fun to build one of these and put the analyzer to it. I think testing things in the real world is a good exercise and I always enjoy working with antennas anyway. Looking in the basement, I found some 3/4 inch copper tubing, a tee, an elbow and a few end caps. The complete list of parts is thus:
¾ copper tubing
78-96 inches (196-244 cm) (frequency dependent)
¾ copper tubing
26-32 inches (66-82 cm) (frequency dependent)
¾ copper tubing
2.5-3 inches (6.35-7.62 cm) (frequency dependent)
Tuning stub short
¾ copper tubing
2 inches (5.08 cm)
Mounting section, bottom of T to MIP threaded adaptor
¾ copper T section
T section for joining main section to tuning stub
¾ copper 90 elbow
¾ copper end cap
End cap on tubing
¾ to 1 inch copper MIP threaded adaptor
1 inch PVC FPT threaded adaptor
Insulating mounting connection
1 inch PVC
Approximately 20-25 inches (50-65 cm)
Insulating mounting material
1 inch stainless steel hose clamps
Attaching the coax to the antenna feed point
RG-8, RG-214, LMR-400 or other transmission line
As needed, including 5-6 turns, six inches in diameter to form RF choke at feedpoint
RF choke needed to keep RF off of coax shield
One important detail to remember when using the above spreadsheet, the measurements are to the closest side and not the center. Thus, if something measures 2.5 inches, it is metal to metal. Some basic soldering skills are required, but assembly is relatively straight forward. In a pinch, almost any conductive material could be used including aluminum, brass, steel, EMT, rigid conduit, or even iron pipe.
Parts cut to size for J-pole antenna on 87.9 MHz
J-pole antenna assembled
J-pole antenna on the antenna testing range
I made this particular J-pole antenna on 87.9 MHz because I didn’t feel like chopping up all my 3/4 inch tubing. Cutting and soldering the tubing took about a half an hour. Designing and fabricating the feed point system another half an hour. I’ll throw another hour in for rounding up the parts, tools, etc. Thus, entire antenna was constructed in about two hours. I used my AIM 4170D to find the proper feed point. If I were going to actually use this antenna, it would then be a matter of finding a mounting location and running the transmission line.
J-pole antenna analysis results
Actually, I was less than happy with this. While the antenna is nice and broad across several channels, there is 16 ohms inductive reactance that is impossible to get rid of. That gives an SWR of 1.4:1, which is not great. With that kind of load, I would be reluctant to run more than a couple of hundred watts into this antenna. The interesting thing is, that graph is the first one, with everything set as calculated in the spreadsheet. After that, I could make the impedance and reactance worse, but not better.
Still, in a pinch, I would use this antenna until something better could be found.
As promised, a picture of the feed point:
J-pole feed point connections
The hose clamps are not optimum, I am sure a better way to attach the feed line to the antenna can be fabricated, but again, I was thinking of an emergency situation and the parts which may be available from local sources.
We have been poking away at this one for the last year or so. It seems that the previous owners of Berkshire Broadcasting had filed for a translator to rebroadcast WNMB, (100.1 WUPE-FM) North Adams in downtown Pittsfield, during the great translator rush of 2003. When the CP showed up in the mail last March, the current owners were quite surprised.
After looking at the Construction Permit, we made some modifications;
Moved the transmitter location from 100 North Street to 1 West Street (Crowne Plaza Hotel) which is the tallest building in Pittsfield. Antenna AGL is 44 meters (145 feet).
Changed the rebroadcasting station from WUPE-FM, North Adams to WUPE-AM Pittsfield
Changed the antenna to non-directional
Changed the ERP from 48 watts to 100 watts
We were able to make those antenna and power changes because we changed the parent station to the local AM station, WUPE, 1,110 KHz. The previous power/pattern was submitted to keep the translator signal within the 60 dBu contour of the FM station in North Adams.
This, I feel, is the best use for an AM to FM translator. WUPE-AM is a class D station with no night time service. Adding a night time service greatly increases the station’s value to the community. While the 100 Watt translator does not cover near as much as the 5,000 watt AM station, the transmitter location is right in the center of Pittsfield, so coverage of the population center is excellent.
The view from the top of the Crowne Plaza is quite spectacular. I am pretty sure I will have a lot of transmitter maintenance to do right about the middle of October.
W277CJ 60 dBu contour
The installation is fairly straight forward:
W277CJ installation, roof of Crowne Plaza, Pittsfield, MA
W277CJ transmitter in outdoor enclosure
The outdoor enclosure is a DDB POD-16DXC which is rather nice, it comes with rack rails and a thermostatic controlled fan.
W277CJ Shively 6812B antenna
The antenna is a Shively 6812B with RADOMES. The transmitter is a BW Broadcast TX600v2. I really like these transmitters, they are well designed and rugged. We have yet to have a single failure of one of these units in the field.
The station ERP is 100 watts, so a small bit of calculating is required to arrive at the proper station TPO. I find it easier to make all these calculations in the decibels per milliwatt (dBm) unit domain, then convert back to watts. Thus, the ERP is 100 watts, or 50 dBm. The antenna has a gain of -3.4 dBm. We used 25 feet of LMR-400, which at 103.3 MHz, has a loss of -0.26 dBm. The total losses are -3.66 dBm, making the necessary TPO 53.66 dBm, 232.27 watts or rounding down to 232 watts.
That is how long it has been since I started this blog. Six years and 727 posts later, I find myself wondering how much longer I can continue this. I have not been posting too much lately because I seem to have run out of things to say. Posting just for the sake of posting seems to dilute the good material with mediocre stuff that has to be deleted later.
The radio business has changed little in the last six years; fewer owners, AM is still plagued with technical issues and poor programming, the FM band is getting jam packed with translators and the occasional LPFM, HD Radio is, well HD Radio.
My situation changed as well with the change in jobs, a new degree, more family responsibilities, etc.
I was thinking about ways to make this more interesting and perhaps doing more with my under utilized youtube channel would be fun. I was called an “old timer” a few months ago as a compliment and I am not sure how I feel about that. After a bit of reflection, I realize there is some truth to it and there are fewer and fewer of us out there that can do what we do. Perhaps some informational things on how to trouble shoot and find problems, what a day in the life of a radio engineer is actually like, radio station people, etc. I know that good trouble shooting is an art form.
I would need a tripod and a better camera.
In the mean time, here are a few statistics from the last six years:
I have typed a total of 812 posts, of which 727 are public and there are about 30 drafts on various subjects hanging out, waiting to be finished and posted. Out date material is usually deleted when I get around to it.
The blog has a decent following, with an average of 700 page views a day, approximately 120 regular readers and 185 RSS subscribers.
There are 3,494 comments and the spam filter has eliminate 1,102,631 useless, fake, ridiculous or otherwise stupid machine generated garbage.
There is also an international readership, with approximately 40% of visitors coming from outside of the US. According to my flag counter, these are the countries that have not visited yet:
British Indian Ocean Territory
Central African Republic
Everyone else has made at least one appearance. I am a little bit disappointed that no one from North Korea has graced our presence.
Top six non-US countries are Canada, UK, India, China, Germany and France.
There are approximately 1,380 images of various interesting things. Most of them are my own, some are borrowed from other sites or the public domain.
I hope that I can continue this thing in some way or format. I have certainly enjoyed meeting many people, reading comments, replies, off line emails and such. It has been an overall positive experience and I value everyone’s input.
I found these old drawings in the filing cabinet and thought they were kind of cool. They look like they were drawn sometime in the 50’s for the WPTR studio at 1860 Central Avenue in the Town of Colonie.
It looks like there was a lot of Neon, including a speller, which I take to mean the sign would spell “W-P-T-R 1540″ then turn off again.
This was the sign for the entrance to the studio building
WPTR sign for front of old studio building at 1860 Central Avenue
I think this is a take off on the old KHJ sign in Los Angeles.
There is some disagreement in the organization that I work with regarding the use of Shielded Cat 5e cable. Is it needed and if so, when and where? Category cables commonly used in Ethernet computer networks and also used for analog audio and other data applications come in a variety of flavors. Shielded (Shielded Twisted Pair or STP) and unshielded (Unshielded Twisted Pair or UTP) Cat 5, 5e and 6 are the most common in radio broadcast facilities.
The main purpose for using UTP and STP for high speed data transmission is common-mode rejection. Cables that are installed in office buildings are subject to various electric and electronic noise sources. Properly installed UTP works to reject these unwanted signals by using differential signaling, which is balanced. Differential signaling can best be described as transmitting information using two complimentary signals that are opposite from one and other.
Noise rejection, differential signaling. “DiffSignaling” by Linear77 – Own work. Licensed under CC BY 3.0 via Wikimedia
The key performance measurement in category cable is Common Mode rejection. Outside noise will introduce a common mode signal on the cable which will be cancelled out by the differential amplifier on the receiving end of the circuit. Proper terminations and good wiring techniques are very important for proper performance.
Using the correct patch panel termination, terminating block or RJ-45 (8P8C) connectors are required to maintain the advertized bandwidth of the cable. There is also a difference in connector and terminating block designs for solid versus stranded cables. Using improper connectors for the type of cable installed can cause dropouts and loss of data.
When installing category cable, care must be taken not to kink the cable, not to exceed the recommended minimum bending radius or exceed the maximum pulling force. Each of these will degrade the cable performance by changing the physical characteristics of the cable. Each pair of wires in category cable has a different twist. Altering these twist ratios by stretching the cable or bending it too sharply will increase the NEXT (Near End Cross Talk) and FEXT (far end cross talk) between pairs. In Gigabit networks, this will degrade throughput and create bottlenecks.
Generally speaking, the minimum bending radius is four times the cable diameter, or approximately one inch for Category 6 cable. The maximum pulling tension is not more than 25 ft/lbs or 110 Newtons.
Category 6, Shielded Twisted Pair
In high EMF environments, shielded cable (STP) can be beneficial in mitigating high electrical noise along with proper installations techniques noted above. Signaling levels on 100BaseT are +1, 0 and -1 volt (MLT-3 Encoding). On Gigabit Ethernet, the levels are +1, +0.5, 0, −0.5 and −1 Volt (PAM-5 Encoding). Induced voltages on in cables from external sources can degrade network performance and create bottlenecks. High EMF environments would include places like transmitter sites and anything on a tower or rooftop. Properly terminated shielded cable is necessary for EMP protection from lightning strikes or other sources. STP has special shielded metal connectors which each category cable class. These connectors supply the path to ground through the RJ-45 jack.
Ungrounded shields are useless.
RJ-45 or 8P8C shielded plug for Category 6 STP
There are also other cable characteristics to consider such as UV resistant jacking for outdoor installations or gel filled (AKA “flooded”) cable for wet locations. Fortunately, there are plenty of sources for these types of cables and they are not terribly expensive.
To answer the question at the beginning of the post; STP can be beneficial at high EMI/EMF or RF sites to mitigate induced voltages on the cable from external sources provided it is properly terminated. In office and studio locations which are not at or next to a transmitter site, UTP is more than adequate provided it is properly installed and terminated.
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.