Q. I'm restoring a radio like the kind used on the Andy Griffith show. Know anything about them?

A. (From Geoff Fors) (internal link) "I know a little :-)"

"There were at least two versions of police radio in the Andy Griffith series."

"The first was a poorly assembled prop consisting of an Eico ham transmitter and VFO. Somewhere along the way they added a Motorola Conelrad Monitor which was a device to alert radio transmitting facilities that a nuclear attack was imminent."

"The radio I assume you are referring to is the last one featured on the series, it was a Motorola Consolette desktop base, the one with the gold 'V' on front and the red batwing 'M' logo which lit up when you transmitted. That radio is from a Motorola series called the 'Twin-V' era. There were three basic series of these stations, L43GGB, L41GGB and L44BBB. They all look the same but L43 is 150 MHz, L41 is 30-50 MHz, and L44 is UHF. You should be able to get a manual on eBay without too much trouble."

"These base stations use a set of three strip chassis inside which were common to a great many Motorola radios, the only difference being the housing they were assembled into. The receiver is a standard 'G' series type and the transmitter is a 25W 'G' strip (except UHF which is 10W.) Even a mobile manual will give you data on everything except the power supply."

"There usually isn't much to restoring these. You get the crystals you want and tune them up, replacing any weak tubes along the way and any dried up capacitors in the power supply. Beware of the remote control consolette which looks almost identical to the base station but is actually just a wireline 600 Ohm remote control for a 6 foot rack cabinet high power station. The remotes have a series of plastic pop-out panels across the lower front where knobs and switches can be added, while the real radios have a solid steel panel at that location."

'You may be able to get a manual right away from Ted at MDM Radio. He has a website with a bunch of manuals listed, although your is pretty old. I think W7FG Manuals also offers a photocopy but his prices are getting ridiculous."

"I serviced hundreds of these radios in another life, they are reliable and will probably outlive all of us. The tubes are all common and easy to get. Most of them have a built-in metering system. If you need more info, let me know."

Regards,

Geoff Fors

WB6NVH

See: http://www.mbay.net/~wb6nvh/chpradio.htm

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Reuters recently reported that Christoph Catselitz of Siemens suggested North American cellular operators using CDMA technology, including Sprint and Verizon Wireless, might switch to GSM technology (internal link).

"I would not bet on North America continuing with CDMA," Catselitz was reported as saying. "CDMA is losing market share globally as the new mobile phone users live mostly in the areas where GSM is the leading technology."

I think this executive's view is flawed and odd. GSM may be growing faster than CDMA but probably because the places it is getting installed in don't yet need the capacity. That doesn't make TDMA based GSM superior. Let's make a comparison.

DSL and its variants (internal link) are the future of internet delivery where landlines exist. Yet most areas without an internet connection get dial up first. It cheaper and faster to install and less costly per month. But we can't say that dial up is the future of the net because it is now growing faster than DSL. Dial up is dead. We're just waiting for the funeral.

CDMA is also the future, even if present customers don't have it yet. GSM operators have already planned the funeral for TDMA based GSM by specifying CDMA for its next iteration, 3GSM. TDMA may linger in low capacity markets or as part of a hybrid system with CDMA, but time based systems are on the way out.

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The History Channel asks its readers to vote for the most important invention of all time. They give these four poor choices:

Light Bulb

Television

Personal Computer

Airplane

The wheel is obviously the most important invention of all time. No argument. We're left, therefore, with discussing the most important modern invention.

The light bulb? Edison did not invent the light bulb. He made a better incandescent bulb, true enough, but his real accomplishment was developing a practical and economical electrical system, from the generator at the powerplant right through to the electrical sockets in a home.

The television? Please. The contribution radio made to the last century far exceeds anything television provided.

The personal computer? The silly thing didn't come into widespread use until the mid-1980s.

The airplane. Hmm. A much wiser choice. I will ruminate on this some more.

I think the telephone, radio, or the transistor were the most important modern inventions. Radio let news flow instantaneously to a nearby city or around the world. For the general public, however, its importance was limited since it worked only one way. You got news, you couldn't send news back.

The telephone eventually tied the world in a web of immediate, back and forth, two way conversations. Knowledge bulding in the last century was so rapid that it can only be compared to the days before and after moveable type was invented. And that building was because of the telephone.

Still, I could argue that the transistor is the most important modern invention. It enabled the Modern Age. Look around you. Your life today could not be conducted with only vacuum tube technology. I'll quit here. Mindless speculating is perhaps only for the mindless.

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Q. Will WiFi clouds and VOIP replace cellular?

A. No. Both technologies will co-exist and co-evolve over the years. Cellular radio's hallmark is mobility, especially over great distances. WiFi works best while stationary. The call you make over the net at Starbucks, while downloading some tunes, won't remain connected when you step to your car and drive away, even with a city wide WiFi cloud. It certainly won't stay connected at 60 m.p.h. while you drive to your next espresso. Cellular radio (internal link) can hold a voice call together in that circumstance, usually, your WiFi connection can not. And your WiFi enabled downloading will certainly stop or slow to a crawl as you go mobile. As speed increases bandwidth decreases, to the point it's no longer useful. Await developments!

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Q. Do you have knowledge of an "Ice Bridge" within a cell site? Or, "Ice Trays"? What and where are they, and what purpose are they for, please?

A. From Mark van der Hoek:

Ice bridges are sections of metal that are installed above cables to protect them from falling ice. They generally run between the tower and the building in which the equipment is housed. In some climates, tower icing is a big problem. Chunks of ice can fall from towers do a surprising amount of damage. It's not unheard of for a 20 or 30 pound chunk of ice to fall a few hundred feet and punch right through a metal roof. If such a missile strikes a bunch of coaxial cables, the damage can be severe.

For a picture, see these pages, be warned, these URLs (all external links) will go away quickly:

http://www.copper.org/applications/elect

rical/pq/casestudy/kgbi_station_A6082.html

http://tinyurl.com/8qqnq

Scroll down to Figure 2. Notice the metal bridge between the tower and the building? That's an ice bridge. It's protecting the coaxial cables which are run beneath it. You can see a close up in Figure 11.

More pictures are at:

http://www.internationaltowersupply.com/

Scroll down and click on the "Ice Bridge" link.

See also: http://www.bettermetal.com/l/index.html

And if you want to see what's left of one after a tower collapse, take a look at:

http://monsterfm.com/engineering/fall3.htm

I hope that answers your questions.

Regards,

Mark

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