Demolitions

[Lopaka]

Just a couple of questions about how demolitions are carried out. How is a new transmitter integrated with an old, smoothly? How and when are tests of a new transmitter carried out?

Are towers generally just trashed, or can they be disassembled for a secondary market?

Do many stations use used equipment?

Is there a secondary market for used transmitters? Would that be domestic and or foreign? Are there many tube type transmitters still in use? Any water cooled still in use?

Thanks for any information.

 

[Robert Bass]

Are towers generally just trashed, or can they be disassembled for a secondary market?

The station I work for, sent off an old tower for recycling. It was a short tower, under 200 feet IIRC. It had peeling paint issues.

R

 

[RadioFixerCLE]

Here is a video of WOR's old towers coming down after 40 years:

http://www.youtube.com/watch?v=8vOdyQoCyqo

I think the way they did that was use explosives to blow the guy wires....the tower would then buckle and fold under its own weight. Tom Ray explains on the video. Believe the metal was sold for scrap -- which would be the obvious smart thing to do ($$).

Needless to say, everyone was FAR away from the old array when this happened.

P.S.: I like the about this video section where the writer mentions the new "digital towers" that WOR built for their new plant. :

 

[Studio1]

Here in New Zealand we re-use a lot of equipment. Being a small country, there is not a lot of second-hand equipment to be had, as the old stuff is often donated or sold to other operators who maybe don't have the budget of the bigger stations.

I'm also an avid collector of old gear - I'm an analog junkie from way back and I still swear by the earlier NON-DIGITAL equipment.

With respect to towers, I'm not sure if you mean AM towers or broadcast towers in general. There is an AM tower up for sale at the moment. It was decommissioned a while ago and has been sitting around.

AM towers generally get well maintained here as they often carry more than one radio service and AM frequencies are still in use in some cities and areas where no FM frequencies are available.

Upgrading of transmitters is usually done by siting the new TX on the floor next to the old one, cabling up and commissioning into a load first off. Then when the testing phase has been completed, the old TX can be shut down and antenna feed shifted to the new TX. This is often done at some hideous hour of the morning like 2:30am when relatively few people will be listening, and the period of time of being off the air is usually minimal anyway.

 

[Sgeirk]

Depends on the buget, market size, and type of service the unit needs to endure. Most stations in major markets are using nothing but the latest gear in say, the past 1-7 years, simply due to their HD broadcast nature.

I know of a station still using the 1947 Winegard 250 foot AM Antenna that they signed on with. Still stands, still works great, still looks great.

We're still using 20+ year old Auditronics consoles.

I know someone who bought an ancient RCA Flamethrower as a backup, only to throw it out a year and a half later. Waste of time, waste of money.

 

[Lopaka]

Here in San Diego there was a naval radio station with towers that had stood since something like 1915 or so. Three huge ones, maybe 300 ft. each, the station had been used for transmitting low frequency naval communications around the world. About 10 years ago it was decided to discontinue the station because it was obsolete, and that meant the towers had to come down. They were a big landmark, you could see them from most of the city, so I drove over to watch the demolition. I remember most the loud whistling noise as the towers crashed thru the air. Actually it was kind of sad seeing a landmark like that come down. I think they gave away some of the material to interested neighbors and sold the rest. I believe a housing development stands on the site now.

 

[TomT]

Towers: Just about four years ago we replaced what was then a 20 year old 200 foot Rohn 45G tower with a new solid steel tower (Rohn used hollow steel tubing). We needed to increase tower height 20 feet to add a pair of 6 foot STL dishes--and the Rohn would not have handled the extra windload.

After carefully erecting the new tower about 2 feet from the old, the tower crew dismantled the old tower and hauled it off. Believe they made two 100 ft. towers out of the old tower for two-way use.

Our 1988 vintage 4 bay ERI FM antenna was taken apart and "o" rings replaced at that time We purchased a kit of spares for the antenna, but despite all that time being beaten upon by mother nature it was remarkably clean inside. (We run 8.6 kw. TPO for 17 kw ERP).

Transmitters. Our main transmitter is a 1988 Harris 10K, it just chugs along, & we've only used three finals since it was installed. Original MX-15 exciter has been moved to backup in favor of a new Armstrong.

Our other station, a class A, uses a 1974 Harris 2.5H. We've bypassed the IPA and drive the final directly with a BE FX-50 exciter(running at 25 watts). The present 1500B final has been in there since 2003. We bought this transmitter for $3500 several years ago, hard to justify replacing it, with electric at 6 cents kw/hr., since it is so simple.

On the other hand, most old AM transmitters use tubes you can't get, and high level modulation schemes that often tend towards high distortion. With new Nautel kilowatt transmitters in the 13K range it is foolish to hold onto the old heavy iron that eats 833A tubes at about $1k per set.

We also have a lot of used equipment in the studios, but you have to know what to buy and who you are buying from. Got burned on a Marti 30 watt RPU transmitter that apparently had been doused with some kind of corrosive fire extinguisher. Worked fine---for a while.