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Newsletter Issue 1

Inside this issue:

Comrex Comments

by Kris Bobo, V.P.

I miss John Cheney. As many of you may know, John Cheney, founder and president of Comrex, passed away in January. I miss the way he’d bring me the latest cool gadget he’d found and I miss his quick wit and funny stories. I even miss his lengthy history lessons. But most of all, I miss his innovative, progressive leadership style. Let me give you an example.

Comrex has always used P&G™ slide faders, even though they are pricey. Last year we found some less expensive faders that seemed to work well and we decided to use them in the Buddy mixer. When the Buddies hit final test, we checked the new faders. None of us were thrilled with them, but we had purchased a large quantity and were committed. I, for one, slept poorly that night. The next morning, I arrived at Comrex to find a memo from John. It read:

"The new slide faders are in the dumpster. You have until noon to talk me out of it."

I knew then that I was working for the right company and for the right man. I miss John Cheney, but I take comfort in knowing that as long as Comrex continues producing quality products, John Cheney will live forever. Thank you John. You taught us well.

Note: Lynn Distler will fill John’s shoes as the new president of Comrex Corporation. Who better to lead us into the new millennium?

John's feet.Jpg (73484 bytes)
John Cheney - Self Portrait

From the Edge of Disaster...

The Conservative Political Action Committee (CPAC) held their annual conference at the Crystal Gateway Marriott in Arlington, VA in January this year and CPAC Director, Tom Katina, decided to include radio talk hosts, broadcasting live on ISDN, during the two-day conference. Katina called Comrex for help, since he’d been told we manufactured equipment to do this. We said we’d be happy to help out with our Nexus ISDN codecs and Buddy mixers, and recommended that he hire a good on-site engineer for the broadcasts.

Several weeks before the conference, Katina placed his order with Bell Atlantic for the ISDN lines and he found Ed Henkel of Silver Spring Communications (also CE of WGAY, Silver Spring, MD) to handle the broadcasts. Everything seemed under control until two days before the conference when the phone company called CPAC to say they couldn’t provision the ISDN. Henkel asked for direct lines and the next day was told there were no cables for analog service either. He then started working through Bell Atlantic, finally talking to a supervisor at midnight who said he’d have an installer at the hotel in 1/2 hour, but all they could give them was five POTS lines, less than half the number they asked for! At 2AM, the lines were hooked up, just in time for the first broadcast to go on at 5AM.

There were five hosts going live during the two-day conference and a total of 62 hours of broadcasts. Henkel didn’t get much sleep, but to CPAC and the talk hosts, everything appeared seamless, with quality and performance no different from the ISDN feeds they were used to. How did Henkel pull it off?

When the phone company bailed out on the ISDN lines, Henkel called us immediately to see if we could overnight some HotLine POTS codecs. (We could and did.) He set up each of the five broadcast stations with HotLine and Buddy mixer, dialing from the hotel back to his studios in Silver Spring and then relaying via ISDN to the hosts’ stations or syndication points. Since both POTS and ISDN codecs are bidirectional, the five lines were just enough to do the job, providing each of the five hosts program audio to the stations with the callers fed back on the return channel.

Katina and CPAC were delighted at how well things went and definitely plan to include radio next year. For Henkel: "It was scary, because I was depending on two different technologies ... but it worked so smoothly."

A Case in Telco Diplomacy

When WATR in Waterbury, CT bought a pair of HotLine POTS codecs, their Chief Engineer, Frank Jankowics, tested them out on arrival and found stable connect rates in and out of his local central office (CO) around 21.6 kb/s. This wasn’t bad, but a similar loopthrough at SFX in Hartford with the same equipment connected at 33.6 kb/s. Frank knew that the phone company wouldn’t claim responsibility for providing a 33.6 connect rate, but he felt that with a bit of diplomacy and help from his telco contacts, he could do better at WATR.

Rather than calling the phone company to come "fix" his lines, he first talked with a phone company friend, a transmission specialist dealing in digital transmission (ISDN, etc.), who suggested if he was running through a non-integrated SLIC*, it may be causing problems. This was indeed the case with WATR, and, after some persistence on Frank’s part and some contacts through his transmission specialist friend, the phone company found direct copper pairs between the CO and the station and shifted his service off the SLIC.

The new line increased connect rates to 26.4 kb/s. But Frank felt there was still room for improvement. Suspecting that the phone company had reinserted loading coils into the new circuit, Frank placed a repair call. The repair technician used a standard device to "ring the line out" and found three loading coils. When the coils were removed, they were still at the 26.4 kb/s rate, but the repair technician was now enlisted in Frank’s project and offered to go through the other copper pairs available and find the best one.

After a few hours, the least noisy pair was found and loading coils removed from it. In addition, the technician found that the line was bridge tapped with an unterminated branch to a local factory and this was removed. Result: a consistent 33.6 kb/s connect rate with the HotLines!

In actual use, Frank usually sets a lower maximum rate to provide a safety margin against errors, but he says "it’s nice to know that it’s there." He adds: "The important thing, since you don’t have control over the phone line at the remote site, is to get the best possible line between the station and the CO, and you’ve gotten rid of half the problem."

To get the "Modem Line Check List" for improving phone line quality:

1. Surf to our website - www.comrex.com. Select TechTips

HotLine Contest

Middleburg Broadcasting Network in Middleburg, Virgina won a pair of HotLines in Comrex’s "Cool HotLine" remote broadcast contest last September, earning the Grand Prize with their coverage of the 40th Annual Fairfax Steeplechase Horse Races on Belmont Plantation.

We checked in recently with MBN to find out what they’d been doing with their HotLines and were delighted to find that they have been very busy. MBN Engineer, Bob Rankin, reports that they have used their HotLines on virtually every remote since they arrived last October.

MBN recently had a demo of the Comrex Buddy mixer and are buying one to complete their remote kit. Rankin says that the HotLine/Buddy combo puts the old road case full of mixers, headphone amps, etc. "out to pasture." He adds that "it doesn’t take much of a technical person these days to be up and running and on the air."

MBN is gearing up for the Virginia Gold Cup which they will cover with a mix of Comrex POTS and ISDN codecs. They plan to use HotLines from the race site to MBN’s studios and then on to ISDN from studio to network satellite uplink. A second pair of HotLines will provide an additional feed to a station without ISDN.

POTS vs ISDN

ISDN should be your first choice for remote broadcasts assuming it is available, not cost-prohibitive, and can be installed in your time frame. If there are big bucks hanging on a remote and you’ve got to be up solid for hours and your job is on the line, ISDN is the way to go.

POTS codecs can be great ... often their performance is comparable to ISDN. However there are some cautions to heed. The performance of POTS codecs depends on the quality of the telephone line dialed. With the HotLine, audio bandwidth is 10 kHz at a connection rate of 33.6 kb/s, but scales down to 4.5 kHz at 12 kb/s. Outside influences on telephone lines (noise, crosstalk, etc.) can cause the modems in POTS codecs to fail during a broadcast, producing several seconds of muted audio while the modems re-establish the link. Also, there is coding delay inherent with these devices and a mix-minus feed is required from the studio to avoid the host being echoed back (This is also true of ISDN.) Finally, note that some POTS and ISDN codecs have roundtrip coding delays of a second or more. These will not be suitable for live interactive programs such as talk. For fixed studio locations, ISDN is still the best choice for program delivery, but for those spur-of-the-moment road trips, the POTS codec can be a very valuable asset.

Note: POTS codecs will not work with cellphones since cellular connections do not provide a sufficient synchronous data throughput.

TechTips

by John Andrews, Tech Support

Although we have found the HotLine power supplies to be very reliable, we have experienced some problems with the mating power supply connector. Several months ago, we switched to a connector from a different manufacturer. The new jack provides a tighter fit for the power plug, improving the electrical connection, and reducing the chance of the plug accidentally being pulled from the jack.

HotLines with serial numbers of 1200 or higher have this new jack. The letters "SWC" appear on the old gray connectors; the new ones are black, with no letters. Any HotLine that has been repaired or upgraded by Comrex since November 1, 1997 has automatically had the new jack installed.

If you feel your HotLine is a candidate for the new connector, call John Andrews at Comrex Tech Support. We can do the change here, or send you the parts and instructions to do it yourself (assuming you’re comfortable with such things).

Note: We recommend using the strain relief provided with the HotLine. If you do not have one attached to your unit, please let us know and we’ll send you as many as you need.

Slick Tricks

  • Use a UPS on your AC feed at remotes - provides surge protection and gives you a battery backup.
  • To get the best quality line at your station for a POTS codec, use one "B" channel of an ISDN line and pull off a POTS port with an inexpensive computer-type ISDN terminal adapter ...e.g. the XRT Express™ by Adtran or the Motorola Bitsurfer™.
  • Put an ISDN line at your transmitter site. Even if you don’t keep a codec and TA there, you can set one up quickly if your regular STL fails.
  • Consider carrying an inexpensive phone to check out PBXs - if you can get a dial tone and dial out, your POTS codec should work. Or try an IBM "Modem Saver," which has status lights to tell you if a phone jack is safe.

FYI - What is the plural of "Nexus?"

A number of customers have asked this. The question frequently comes after saying those soothing words "I’m planning to buy four Nexuseses!" At this point, we’re so charmed that we won’t rush to correct you.

However, in the interest of setting the record straight, we are happy to inform you that the plural of "Nexus" is "Nexus." It is a fourth declension Latin noun, meaning that both the nominative singular and plural endings are "us."

So, please feel free to order as many Nexus as you’d like. We won’t correct your grammar.