Pittsfield Massachusetts’ newest “Metro-Station” 103.3, W277CJ

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
W277CJ 60 dBu contour

The installation is fairly straight forward:

W277CJ installation, roof of Crowne Plaza, Pittsfield, MA
W277CJ installation, roof of Crowne Plaza, Pittsfield, MA
W277CJ transmitter in outdoor enclosure
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
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.

Six years

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:

  1. 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.
  2. The blog has a decent following, with an average of 700 page views a day, approximately 120 regular readers and 185 RSS subscribers.
  3. There are 3,494 comments and the spam filter has eliminate 1,102,631 useless, fake, ridiculous or otherwise stupid machine generated garbage.
  4. 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
    • Christmas Island
    • Comoros
    • Guinea-Bissau
    • Mayotte
    • Nauru
    • Niue
    • Norfolk Island
    • North Korea
    • Saint Barthelemy
    • Svalbard
    • Timor-Leste
    • Tokelau
    • Tuvalu

    Everyone else has made at least one appearance.  I am a little bit disappointed that no one from North Korea has graced our presence.

  5. Top six non-US countries are Canada, UK, India, China, Germany and France.
  6. 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.

The old school marketing campaign

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.

WPTR-billboard

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
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.

Shielded Category Cable

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
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
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
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.