Edom Hill AM Array Digs Out

On the morning of Sept. 8, 2014, an unprecedented storm ravaged much of the area around Palm Springs, Calif., in particular the top of a small desert spot known as Edom Hill.
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On the morning of Sept. 8, 2014, an unprecedented storm ravaged much of the area around Palm Springs, Calif., in particular the top of a small desert spot known as Edom Hill. This is just north of the I-10 freeway in Cathedral City, nestled among the small cities that make up the Palm Springs area and known locally as Coachella Valley.

I am vice president of programming and operations for CRC Broadcasting based in Phoenix. Our CRC Media West business operates two AM stations whose transmission facilities are at the base of Edom Hill.

They are KXPS, licensed to Thousand Palms, and KPSF, Cathedral City. They share the transmitter site, powered by generator and diplexed into a five-tower array. KXPS at 1010 kHz has been licensed for decades. KPSF at 1200 was put in several years ago by Mueller Broadcast Design.

The facilities supporting these two stations were damaged in the 2014 storm, as the accompanying photos demonstrate. The repairs described here were coordinated by my two fantastic engineers: Bill Watson, our local engineer (and first on the scene); and Mark Mueller of Mueller Broadcast Design. I spent my time coordinating crews of earthmovers, scheduling on-site, managing cleanup of the ATUs, repairing copper radials and lending assistance where I could to the engineers, who understood all this far better than me.

Figure 1 I don�t feel I�ve ever taken engineers for granted in my 18-year career; but I certainly grew to appreciate them all the more after this incident.

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CASCADES

As you see in Fig. 1, our Towers 1-4 run northeast up the hill while Tower 5 sits west of the transmitter building. About 1,200 feet or so south of the building is Varner Road, a two-lane used mostly for construction, with no commercial offices or useable electrical power. It runs west of Bob Hope Drive and east of Date Palm. The road is designed so that through traffic � trucks headed for the trash facility at the west end, utility trucks servicing electrical lines � can pass through.

Figure 2
Intense amounts of rain in a short period of time essentially caused a collapse of mud and debris from near the top of the mountain in what many locals called a �100-year storm.� Cascades started about 1,000 feet higher and by the time they washed past inside the guy wires west of Tower 3, the widest stream was 14 feet across.

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Figure 3
Much of the water accumulated to meet at our Tower 2 with an 8-foot swell about 10 feet wide. If you look again at the map in Fig. 1, taken before the storm, you may notice that a tiny water runoff had trailed to Tower 2 over the years, though it had never caused damage. In the September storm, water followed this best path down the hill.

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When the rain and mudslides were done, two miles of nearby Varner Road were covered with 4 to 6 feet of mud. Fig. 2 represents a view from Varner Road after the storm removed all shrubbery. Fig. 3 shows a 26-inch long pipe where water has taken out part of the road.

Immediately after the storm, Bill Watson walked up from I-10 to the site to assess the damage. He could bring nothing but a basic set of tools with him.

THE DAMAGE

He realized quickly that Tower 2 would be out of service for a while. Thinking quickly, he noticed that Tower 5, on high ground, was unharmed. He put us on a temporary broadcast for both stations using that tower alone.

But the erosion around the entire area had created massive problems at the site.

About 12 inches of ground cover had washed away, exposing radials and large pieces of copper strap.

Flood waters had caused mini �ravines,� pulling and stressing the buried transmission lines serving KXPS and running from to four of the towers. The conduit used to create a basic cover for transmission and sample lines had been pulled out of the ground in almost every position and whipped around as if it were nothing.

Figure 4
Further, the flood waters that collected coming down within the guy radius of Tower 3 had created a path that cut straight through the deeply buried 7/8-inch coax, 3/8-inch sample line and control cable running to Tower 4. The path where the cut occurred was 13 feet across at that point and about 4-5 feet deep.

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Figure 5
Figure 6
Fig. 4 shows copper strap that connected ground radials between Towers 2 and 3. Fig. 5 shows the �Y� split for transmission lines that ran to Towers 3 and 4.

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If you look closely at Fig. 6 you�ll see the transmitter building to the north, just west of Tower 2. The area in the photo had been part of the transmitter access road into our facility, which was now washed out.

The water that had collected and crashed into Tower 2 submersed the ATU boxes and the filter box mounted to the side of KXPS�s ATU in silt-type sand, very fine in texture.

CAN-DO ATTITUDE

The first major hurdle was to get fuel up the hill to our tank, because tankers were unable to drive in.

Our engineers sought an alternate route that could be created quickly within our leased property area. This would have to be created without new soil and placed clear of any ground radials. They decided to start a road from Varner about 400 feet west of the first road, then head up the hill around the west side of Tower 5. The earthmoving team was Maco Engineering based in Cathedral City.

Figure 7
Within four days we had a serviceable path on which fuel trucks could resume driving. Fig. 7 shows the new road, represented by the blue line, with radial estimates in orange.

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Once the new road was taken care of, we needed to pull up the transmission line, sample line and control cables that had moved around. We had to dig them up and retest them before repair could proceed further.

Figure 8
Notice the red arrow in Fig. 8; it points to a rectangular metal object. At first we thought this was the �guts� of the ATU box serving KXPS; but after several hours spent extracting it from underneath, we discovered that this was in fact an old window air conditioner unit that had been dumped up the hill and used for several years as target practice. It had washed down in the storm and ended up under this ATU. It thankfully had been able to stand up to enormous direct pressure. This box quite possibly was the only reason the tower itself wasn�t nudged or damaged.

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Figure 9
But this had all been underwater during the flood, as you can see from the dirt and soil atop the ATU box, Fig. 9.

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The KXPS ATUs had been mounted on a concrete base with two pieces of thick angle iron. Those were bent backward and pressed all the way up until about 6 inches from the actual tower.

Figure 10
Fig. 10 also is revealing. Notice that sand and soil underneath the ATU�s concrete base is washed away; you can see the bases for the chain link fence supports. The gray conduit is KPSF transmission line for Towers 1 and 2.

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Figure 11
Figure 12
Internal damage to the ATUs was massive. Fig. 11 shows the outer door open, exposing the inside metal panel that protects the contents from the elements and protects users against electrical shock. To the right side of that picture, note the space separating the structure from the filter box that serves both stations. The sheer force of the water and mud that flowed over it had not only bent back the entire box but nearly sheared the screws that mounted the filter box to it. The KPSF ATU is out of the frame.

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Figure 13
Figure 14
Fig. 12 is the lower right side opening of Tower 2�s ATU. The dirt is more of the caked-on silt type sand that had washed into a fairly well sealed box. You can see the day/night contactor switch mounted on the back wall. Fig. 13 is the filter box for the two stations. Around the northeast corner of this tower was Fig. 14, the ATU for KXPS, filled with sand and mud but structurally intact.

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CLEANUP

Once we�d assessed the damage we began the cleanup process.

I went out and dug out the components in the ATUs by hand. Not knowing what was within, I had to proceed slowly and deliberately over several days to avoid damaging components. The back of the cabinet showed that mud had reached 17 inches from the base; see Figs. 15 and 16.

Figure 15
Most of the coaxial transmission lines tested very well. Sand had blocked the gates of all our fences so we dug those out. All of the new lines that went to Towers 1, 2, 3 and 4 showed stress at the junction points, but a team of four men with shovels managed to get those lines set properly. We had to replace a contactor in KPSF�s Tower 2 ATU, and a component failed after the first test in the Tower 2 filter box.

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After repairing and/or replacing lines to Towers 4 and 2, we re-buried all of the line runs, repaired the fence at Tower 2, repaired many copper radials and moved hundreds of tons of earth back over exposed copper. Then we tested all lines and were back to full strength.

In review, because we�d been facing substantial expense and had no flood insurance coverage we split our project into four parts:

Figure 16
Basic recovery. This was mostly Bill Watson getting us the early reports before we could get vehicles on site. During this time we had the earthmovers come in and create a new road to resume fuel deliveries.

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I coordinated a team of guys to dig up the conduit for inspection. We then scheduled our consultant Mark Mueller, who assessed damage, did some basic repairs and got us to a reasonable operational status. We left at this point to test components that had simply been cleaned rather than replaced.

Before we had our consultant on site again, we experienced a failure at our Tower 2 filter box and replaced a Jennings UCSXHF-450-35S vacuum capacitor that had sustained damage. With that repaired, Mark came back on site, repaired remaining components and ran successful tests.

Re-burying lines, repairing copper, moving lots of earth, repairing the fence line around Tower 2, and installing a cattle gate to restrict entrance were the last few steps.

So it took about 12 hours to get back on the air, two months to improve the signal and about five months before we were fully �back to normal.� Amazingly, in spite of the ordeal and damage, once we got everything cleaned up and put back together, both systems came back up and are operating normally, requiring only minor adjustments.

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