Engineering Radio – Page 6 – One Hundred percent Human Generated Content for your Reading Enjoyment

WKIP; removal of the taller tower

This is the original tower for WKIP, but not the original antenna. It was put up circa 1960 or so and like many towers from that era, has hollow legs. Thus, after 60 years or so, it is deteriorating from the inside out.

This was part of a two-tower directional array. It is odd that a class C station on 1,450 KHz would have a directional antenna at all. Even stranger still, it was directional daytime, non-directional night, both at 1,000 watts. The reason for such an odd situation; the station was co-owned with WGNY in Newburgh and the daytime coverage contours would have overlapped without a directional array. The taller tower is 215 degrees tall with top loading. During the daytime, the pattern goes to the North and it covered very well.

Vertical Bridge, the tower owner, decided it was time to replace the aging structure with a monopole. They are completing the project this summer. Our part is to move WKIP to the shorter tower and put up a temporary FM antenna for the translator. Once the project is completed, WKIP will operate from the shorter tower (which is 85 degrees) permanently, getting rid of the now unnecessary directional antenna on a class C channel. The translator antenna will move back to the monopole, once it is put up.

Problems… Yes, we have a few of those…

First, the short tower had a broken guy wire. Actually, the guy wire was fine, but the lowest grip connecting to the equalizing plate was rusted through. It is fortunate that this was discovered because the upper guy wire was getting ready to let go too. Northeast Towers was able to replace all of the grips on that set of guy wires and re-tension the tower. They did a full investigation of all of the other anchors prior to any climbing. This is in a swamp, which has flooded several times over the last few years.

Tower #2, guy wire repaired, Scala FMVMP translator antenna mounted

Next, the temporary FM translator antenna was hung on the tower. It was thought that the 3/8 sample line from the old AM sample system could be used as a temporary transmission line for this system. Unfortunately, that line turned out to be 75-ohm cable TV drop line and was not suitable for transmission of VHF. We had about 600 feet of leftover 3/8 sample line (Cablewave FCC 38-50J) from a decommissioned AM site, so we used that instead. It has quite a bit of loss on VHF, however, for temporary use, it will work.

Next, it seems this black rat snake had taken up residence in the ATU cabinet. The bottom of the ATU was full of mouse nests going back many years. One of our employees dutifully cleaned out the mouse nests unknowingly under the watchful eyes of this snake. Only after he was done, did he see the snake coiled up on the disused current meter shunt. There was a mild freakout for several minutes, but the snake left on his own and we got back to work. The black rat snakes are helpful to have around, but perhaps best if he stays outside of the ATU. We will seal up the entryway for the coax, which seems to be where all the critters are coming in.

This Kintronic Isocoil was mounted to the back of the ATU with unistrut. Even though this is a temporary installation, I have found that sometimes temporary things can last much longer than anticipated. Besides, it was easier than trying to use pressure treated 4 x 4 lumber.

Next, we measured the ATU with the fancy machine (Agilent E5061B network analyzer). In theory, the ATU input should be 50 ohms to match the incoming transmission line. No, instead it was 38 Ohms -j20.

So, a little bit of a retune was required. With the fancy machine, we were able to get it to 52 ohms -j9 or so. This is good enough for now, there will be numerous cranes in the air and the station has an STA to run at 250 watts for the project’s duration. After the new monopole is up, we will measure the base impedance of the tower and tune up the ATU for 50 ohms and then return the station to full power at 1 KW.

Smaller crane, used to assemble the larger cranes

The old tower coming down:

Top section and top loading wires separated

Two cranes were used; one to hold and lower the tower section, the other to lift two tower workers to cut away the sections. The tower was deemed unsafe to climb, therefore it had to be removed like this. It was also unsafe to drop because of the proximity to the studio building and the other tower, which is being retained.

You get the idea. These tower sections and guy wires were cut up and put in a scrap metal dumpster. They will be recycled into something else.

Now, they will work on removing the old tower base and putting up the monopole. Once that is done, we will tune up the AM on the short tower and get it back to full power.

Digital Audio Broadcasting Survey results

I have been looking over this data for a few weeks and there are some interesting data points. First, I would like to thank everyone who participated. This is not a scientific poll, but rather an informal survey of those who chose to participate.

The survey consisted of ten questions and was posted on Facebook, Reddit as well as Radio World. There were 114 responses, which is a relatively small sample size and is less than anticipated. There were 5 people who opened the survey and then did not take it. This may indicate a level of apathy towards the subject. Most responses were from the United States, but there were a few from China, Europe, and Brazil. The average time to complete the survey was 1 minute 40 seconds.

The first question was a warm-up question and it shows a lukewarm response at best with the top two responses being “It’s Okay,” or “I am indifferent.”

A vast majority of respondents feel that testing other Digital Audio Broadcasting systems such as DRM30, DRM+, or DAB+ would be a good idea. In MB docket 19-311, the FCC left the door open for such testing in the future, stating in paragraph 26 “Finally, we (the FCC) emphasize that by approving use of HD Radio technology, we do not foreclose the possibility of authorizing alternative technologies in the future, if they are properly before us.”

Question #2 was an attempt to find out where most people are listing to HD Radio and radio in general. Not a great surprise that it is mostly in-car listening. The in-home listening is a little bit surprising. What is even more surprising is that 30% of the respondents do not have an HD Radio. HD Radio has been the digital audio broadcasting standard in the US since October 2002, when the FCC first authorized its use. Receivers are still an issue some 20 years into the project. I know that when I purchased a new vehicle (Ford) in April of this year, HD Radio was not an option in any but the highest trim packages. My first HD Radio receiver was a tabletop Sony XDR-S3HD purchased in 2006 or so for $200.00 which was a lot of money. A quick look on Amazon shows that the least expensive HD Radio is the Sangean HDR-14 for $70.00.

Questions #3 and #4 deal with the “analog sunset,” as originally proposed by iBiquity, the developer of HD Radio technology. After a period of time, according to the original plan, stations would turn off their analog signals in favor of all digital transmissions. In October of 2020, MB Docket 19-311 the FCC has allowed AM stations the option to do just that. Thus far, four AM stations have transitioned to all-digital broadcasting, one of which is off the air since the owner passed away.

According to the survey respondents, by a slim margin of 53-47%, all-digital AM is supported. The FCC has yet to consider all digital FM and by an equally slim margin of 46-54%, all digital FM is not supported.

Question #7 asks about perceived audio quality. I received a few email comments about this question. Three respondents noted worse audio quality on HD-2, HD-3, or HD-4 channels due to reduced bit rate CODECS. Five people skipped this question.

This gets to the crux of the problem; for radio station owners, it is expensive to purchase and install HD Radio equipment. If there are no great perceived improvements, what is the point? I find AAC audio codecs to be okay, however, there is a noticeable difference between CD player PCM and streamed audio no matter what the source. Low-bit rate codecs sound like they are coming from underwater. Why do we listen to the radio? Information and entertainment. I posted something many years ago: Listening to the Radio is like doing Cocaine. For the maximum dopamine effect, I like my music to sound like music, not some watery approximation.

Question #8 asks about additional features, most people find Program Associated Data (PAD) useful. Even in non-digital FM stations, RDS is an important feature and stations will get phone calls if the RDS is missing or stuck on one song for a prolonged time. Listeners have become used to glancing at the radio to answer that age-old question; what’s the title of this song?

In response to question #9 (How many hours per week do you listen to the radio (including streaming terrestrial broadcast radio stations via a website or smart device)? The average was 19.6 hours with a minimum of half an hour and a maximum of 90 hours. Interestingly, there were four people who put in 0 weekly listening hours.

Question #10 is very interesting. In spite of the lukewarm feelings it seems that most respondents would favor the FCC mandating a transition to all digital audio broadcasting by a margin of 62% with most opting for “at some point in the future.”

HD Radio has been stalled for some time. The technology has not lived up to the hype and for most stations, it is a way to feed an analog translator with additional programming. There is an overall lack of interest, the majority of those who did take the survey stated HD Radio was “okay.” Receivers are expensive and still difficult to obtain. All digital AM (HDMA3) has not progressed very far since the FCC allowed its use. Yet, the people who did respond felt that additional testing of various Digital Audio Broadcasting systems should be allowed. I don’t know, that ship may have already sailed.

Fixing the switching power supply

This particular power supply is used in Broadcast Electronics AM1A, AM2.5E, AM5E, AM6A, AM10A, FM1C, FM10T, FM20T, FM30T and FM35T transmitters. It is a Computer Products NFN 40-7610, 40 Watt, +5 VDC, +/- 15 VDC BE part number 540-0006.

BE AM1A ECU power supply, C-15 marked with pen for replacement

Generally, one component fails over time on this unit, C-15 which is a 680 uF 35 V electrolytic capacitor. When that capacitor dries out, the power supply will fail to start, do odd things like start and fail after a second or two, or cycle on and off. This will happen after the transmitter has been off for a few minutes. Replacing C-15 with a 1000 uF 50 V capacitor will fix the problem. There is enough room for the larger capacitor if the leads are left a little bit long.

BE AM1A repaired ECU power supply re-installed

We have several of these repaired units on various shelves at various transmitter sites.

As always, when replacing electrolytic capacitors, pay attention to the polarity otherwise this will happen:

Blown Electrolytic Capacitor installed backward

I suppose somebody was in a hurry to get home that day. After I installed this repaired unit, it ran for about 15 seconds and then there was a pop. I opened the door on the ECU and white smoke was wafting out from under the power supply cover. Since the Pope is still The Pope, I knew it was the electrolytic capacitor.

Our beloved BE AM1A is back in service. This transmitter is 22 years old and we can keep it going for as long as parts are available.

Salvaged classic equipment

During the early days of COVID, we were engaged to move a studio out of an old location in a hurry. There had been a long-simmering dispute with the landlord, who finally changed the locks (illegally), but then gave 30 days’ notice, and so on. Regardless, we were building a new studio a few blocks away and were told to take anything usable, which we did.

I noticed the old RCA on-air light for one of the studios and the owner said he’d like to have that installed at the new place. There were two other ones that were not working. In total, we ended up with three of these:

As far as I can tell, they dated from around 1960 and were filthy. Sixty years of dust, dirt, cigarette smoke, etc needed to be scrubbed off of them.

The original light bulb was a bi-pin 110-volt incandescent lamp. Over the years, the sockets became brittle and fell apart.

Rather than trying to source replacements for the lamp holder, I figured it was easier to install a 12 VDC LED module. That way this would become a low-voltage device and the LED module should last for as long as the studio is in use.

I took the two best units and installed them in the new studio. One of those units needed minor touchups to the black paint. The third unit’s paint was in bad shape. I opted to strip off all the black paint and repaint it, this time with red.