Field Report: Clenney Communications Optelator II

December 1, 2004

During the past several years we noticed an increase in electrical storm activity. On one occasion, our telephone company-supplied T1 smartjack and Burk remote control ESI card were damaged beyond repair. Thinking that this was an isolated case and performing a visual check of the building and telco ground system, I didn't see anything that obviously changed. Then we had a second strike two months later.

We sustained substantial damage to our smartjack card cage and Burk remote control again. The Burk lost both I/O cards, the CPU board and ESI, making it virtually a complete loss. I exhaustively searched for anything that may have changed in the grounding system. Finding nothing out of place, I began beefing up the protection schemes.

Performance at a glance
Optically isolates POTS lines
Full-duplex operation
Provides 75kV isolation
Less than 1dB audio loss
RJ-11 connections

The telephone company installed a terminal block that contained gas tube arrestors, and I checked and cleaned all connections leading to the building ground system. All seemed well until the third strike that next storm season.

That was enough. I looked into other means of protecting the system and found the Clenney Communications Optelator. Once installed, the Burk ESI card sustained no further damage, even when the telco T1 smartjack was hit.

What it is

The Optelator is a POTS line isolation device that inserts a 3¼" air gap between the telco main line and the device connected to the line. In this case, we used it in front of the ESI card on the Burk ARC-16 remote control. The two halves of the unit are connected by two optical fiber cables that connect two circuit boards to one other.

The Optelator receives power from a 24Vac, class 2 wallwart transformer that connects to the same end as the equipment that it is protecting. This end also has LED indicators for power, off hook and ring detection.

The opposite end is connected to the main telco line, and it has a black reset button and a loop LED. Both telco connections are standard RJ-11 jacks with all four pins used. The case is made from a see-through smoked plastic with dimensions of 10.5"L × 3.25" W × 1.75" D and it weighs about 1.5 pounds.

I installed the Optelator as close as possible to the remote control by attaching it to an aluminum rack panel and mounting it below the Burk's interface panels. Two RJ-11 jumpers were connected from the Optelator to the Burk and from the Optelator to an RJ-11 adhesive wall box main line mounted to the rack sidewall. The power cube was plugged into the same UPS as the Burk to ensure access if power failed and the generator failed to start automatically.

The unit requires no maintenance. The case is glued shut. There are no screws and the case has a label that reads, “Do not open, no serviceable parts.” The unit carries a one-year warranty. While this may be a detractor for some, the unit worked for quite some time, preventing any damage to the remote control.

Inside view of the unit showing the fiber optic protection connection.

While the unit was easy to mount on my own, I would like a 19" rack-mount kit made from the same plastic, or even a redesigned case so that it can mount in a single rack space. I didn't feel comfortable mounting it on a conductive surface and Runnels cautions against it. However, we needed the unit located as close to the Burk inside the equipment rack as possible. Ideally, the plywood at the main telco entrance would be used for a mounting surface, but that is too far away to prevent a strike from being induced into the interconnect between the unit and the protected equipment. This proved to be a good choice, because the lightning was entering through equipment located in the rack next to the Burk.

Peace of mind

The Optelator offers great peace of mind that it's protecting the equipment from all potential lightning damage. I recommend using one for all installations where lightning may be even the slightest issue.

Clenney Communications

For us, the Optelator bought us some time while we reviewed all buried ground connections, including the tower and coaxial grounding kits to find anything that was compromised. In the end we found and repaired several problems, but the Optelator's main telco line input side ultimately failed from repeated hits. It served its function, preventing the costly damage to the remote control.

Ternovan is the market chief engineer of Infinity Columbus, OH.

Editor's note: Field Reports are an exclusive Radio magazine feature for radio broadcasters. Each report is prepared by well-qualified staff at a radio station, production facility or consulting company.

These reports are performed by the industry, for the industry. Manufacturer support is limited to providing loan equipment and to aiding the author if requested.

It is the responsibility of Radio magazine to publish the results of any device tested, positive or negative. No report should be considered an endorsement or disapproval by Radio magazine.

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