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#11
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![]() "BNB Sound" wrote in message oups.com... So, what else is out there. I know the military has always been heavily invested in radio gear, but what else was (and is?) there? Jon KC2PNF AT&T High Seas Radiotelephone Service could be used by any ship with high-frequency single side band radiotelephone service. Worldwide in scope, the service provided two-way voice communication between ships on the high seas and telephones on land, at sea or in the air. While I was employed at A.T.&T. I was given a tour of their international operating center in Pittsburg PA in the early 1990's. Being a ham I most enjoyed watching the operators at the High Seas Bureau taking calls from and to ships at sea. Staffed 24-hours a day, 365-days per year, AT&T operators at Pittsburg PA provided mainland telephone connection to ships at sea. In many circumstances, operators handled distress calls. The operations staff was trained for all emergency situations and alerted the Coast Guard of pending crises. AT&T High Seas Radiotelephone Facility - was the only facility of its kind in the world, provided lifesaving, two way voice radio-telephone service communication between ships at sea, or aircraft, and telephones on land, sea, or in the air. WOO was the radio call sign of the now-defunct AT&T High Seas Service. The radiotelephone transmitter station was in Ocean Gate, NJ ( 39°55'38?N, 74°06'55?W) and the receiver station was in Navesink, New Jersey, USA. Before satellite communication systems were widely available, the only way ships at sea had to communicate with the rest of the world was via HF SSB connections to land stations. The AT&T high seas service consisted of WOO Ocean Gate, New Jersey and her sister stations WOM Pennsuco, Florida (Miami, Florida) and KMI Dixon, California (Point Reyes, California). A vessel at sea would make radio contact with one of those stations, and the operator would patch the radio connection though to a telephone call made over the PSTN. The charges were typically settled by making the landline connection a collect call. Larger vessels maintained accounts with AT&T. In the years prior to regular telephone service being available in Mexican towns such as La Paz, Cabo San Lucas and Puerto Vallarta, KMI provided service to certain hotels and resorts in those locations. Sometimes a hotel would register a land based transmitter as a yacht, and give it a fictitious name in order to provide phone service to their customers. AT&T shut down all three stations on November 9, 1999. It is believed that the only remaining commercial sources of high seas high frequency radiotelephone service are WLO in Mobile, Alabama and KLB in Seattle, Washington. AT&T now uses "Mobile Satellite Services". To use the High Seas Radiotelephone Service, each ship's radio officer would select a channel to call one of AT&T's Coast Stations. A technician at the Coast Station will then pass the call to an AT&T operator in Pittsburg PA . The person at sea would tell the operator the number he or she was trying to reach and the call was connected. People on land would call 1-800-Sea-Call and tell the operator in Pittsburg PA the name and callsign of the vessel they wanted to call. Ace - WH2T .. |
#12
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![]() "BNB Sound" wrote in message oups.com... I've been an amateur operator for a little over a year now and one of my favorite parts of the hobby is soaking up stories from previous decades. One of the things I'm curious about is professional HF work. I've heard it mentioned in passing that when the early trans-Atlantic cables went down they would shift to HF circuits as available to try and pick up the slack. So, what else is out there. I know the military has always been heavily invested in radio gear, but what else was (and is?) there? I'd love to hear from anyone who ever brought home a paycheck for working the airwaves. I used to run a company in Tanzania that supplied HF radio kit to NGO's Mines, Aid agencies, Safari companies,Farms, Shipping and transportation companies. Not much of a mobile phone network away from the cities. Also we provided a HF email service called Bushmail, similar to Sailmail using Pactor 3 SCS modems for HF email. HF kit that we supplied Kenwood TRC 80/TK88, Icom IC-78/IC-718, also some kit from Codan and Motorola So, yes there is a business market for HF comms kit in Africa. Robin |
#13
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On Wed, 9 May 2007 15:23:30 EDT, AF6AY wrote:
On a more consumer-oriented basis, the broadcasting industry is generally wondering what will become of all those old analog TV transmitters after the transition to HDTV in the USA. There's no easy answer for that, either. Do not confuse digital television (DTV) with high definition TV (HDTV) which is a subset of DTV. All TV stations will be required to use DTV but the use of HDTV is optional. As far as the transmitters go, in general they are being junked because most of them are near the end of their useful lives and are held together by duct tape and baling wire in anticipation of the transition. 73 de K2ASP - Phil Kane Life Member - Society of Broadcast Engineers |
#14
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On Sat, 12 May 2007 04:47:18 EDT, "Dr.Ace" wrote:
AT&T High Seas Radiotelephone Facility - was the only facility of its kind in the world, provided lifesaving, two way voice radio-telephone service communication between ships at sea, or aircraft, and telephones on land, sea, or in the air. I beg your pardon - most if not all major coast stations throughout the world had that capability. I was involved with the Israeli coast station - 4XO in Haifa (Haifa Radio) - in the mid-60s and I knew that all of the European coast stations had HF SSB voice service available as well. Before satellite communication systems were widely available, the only way ships at sea had to communicate with the rest of the world was via HF SSB connections to land stations. Uh, are we forgetting CW and RTTY (later SITOR) TELEX HF which did not use AT&T's network? Sometimes a hotel would register a land based transmitter as a yacht, and give it a fictitious name in order to provide phone service to their customers. Two brothels in a remote area of Nevada (where such activity was legal) tried that in the late 70s and the VHF Marine carrier who colluded in that lost his license and equipment as a result. -- 73 de K2ASP - Phil Kane From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon e-mail: k2asp [at] arrl [dot] net |
#15
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Phil Kane wrote:
On Sat, 12 May 2007 04:47:18 EDT, "Dr.Ace" wrote: snip Sometimes a hotel would register a land based transmitter as a yacht, and give it a fictitious name in order to provide phone service to their customers. Two brothels in a remote area of Nevada (where such activity was legal) tried that in the late 70s and the VHF Marine carrier who colluded in that lost his license and equipment as a result. They yacht to have known better than that.... ;^) - 73 de Mike KB3EIA - |
#16
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Phil Kane wrote on Sun, 27 May 2007
23:00:15 EDT: On Wed, 9 May 2007 15:23:30 EDT, AF6AY wrote: On a more consumer-oriented basis, the broadcasting industry is generally wondering what will become of all those old analog TV transmitters after the transition to HDTV in the USA. There's no easy answer for that, either. Do not confuse digital television (DTV) with high definition TV (HDTV) which is a subset of DTV. All TV stations will be required to use DTV but the use of HDTV is optional. I made an "aside" for comparison and haven't confused anything. Firstly, DTV isn't about using HF spectrum...I am very aware of that. The transmitters for television represent a sizeable capital investment by broadcasters. I am aware of the complaints of the broadcast industry (pro and con) during the entire time of the "Grand Alliance" testing that led to the eventual DTV broadcasting format that went into broadcasting regulations. It's been years since I "rode gain" at a control console or "took" a particular camera or tape unit, but I do know something of the MPEG video transport format even though it generally gives me considerable confusion every time I've studied it. :-) The MPEG video transport format can accommodate four different pixel arrangements and DTV receivers are supposed to be built to decode all of them automatically. That video format includes the old-style analog format (converted from analog to digital) on up to the High- Definition TV which is considered by most consumers as "wide screen TV." The DTV transmitters themselves handle the entirety of the video format sent up from the studios,including the quadraphonic sound, text for hearing impaired, and whatever else the studio central control sticks in there. In the old TV transmitter arrangements of any appreciable power, they were almost always TWO, one for video (AM sorta SSB called "vestigal sideband"), one for audio (FM) with a Diplexer (passive filter) to connect both to the same wideband antenna. The DTV transmitter is a single one since ALL of the modulation information is conveyed by it, no "extra" one for sound, seldom any need for an external filter, let alone a diplexer. The internal design of the DTV transmitter HAS to be different than either the AM video or FM aural transmitters by nature of the modulation mode. But, that DTV transmitter can handle ANY of the video transport formats automatically. Whether the TV station central engineering sends old NTSC video converted to "low grade" digital format or has gone all-out to run everything in "high definition" doesn't bother the DTV transmitter. The end result for conversion to DTV was a replacement of the transmitters (old) by one new one. Draconian for the broadcasters but visual and audible pleasure for millions of consumers receiving the DTV. As far as the transmitters go, in general they are being junked because most of them are near the end of their useful lives and are held together by duct tape and baling wire in anticipation of the transition. I disagree with that "junk" figurative phrasing. Here in Los Angeles, there is one central TV (and most FM) broadcast transmitter site, Mount Wilson. It's been a few years since I was up there but all the stations (7 on VHF, 4 on UHF) had good, long-lasting transmitters. At the time KTLA (ch. 5) was beginning to convert to DTV; they were a pioneer broadcaster in L.A. and this year is their 60th anniversary here. Both studio and transmitter sites have excellent equipment and their DTV signal is absolutely HDTV. Their morning show content is, in my view, JUNK, but that is CONTENT, having nothing to do with equipment or signal quality...a personal critique. What used to be a TV "leader" in quality of equipment, NBC (ch. 4) under the 'general's" eye of RCA, hasn't fully converted to HDTV in their studios. NBC evening news is HDTV but local news is still narrow TV. NBC is owned by General Electric and "RCA" exists solely as a brand name now. I think...haven't kept up on the mergers and acquisitions of large corporations lately. :-) TV is above 30 MHz, definitely not in the HF spectrum. However the type and kind of modulation carried by any transmitter will determine whether or not it will be "junked" for a new replacement, NOT it's supposed "held together by tape and bailing wire." If hams could run 4 KW PEP SSB on HF (not in the USA) then the ages-old Western Electric LD-T2 SSB transmitter would be a great surplus bargain for them...Class A stages up to the PA which is AB_2, push-button QSY to any one of 10 pre-tuned frequencies. Problem is, the SSB format is 12 KHz wide and has internal frequency multiplexing for four 3 KHz audio inputs combined for the output SSB modulation. A no-no for amateur radio use, even if well-designed after WW2 by WE. Too much modification required to fit the "tranditional" and technical specs even if a superb design for its intended use. That was the general point I was making, not something about the video format of DTV. 73 de K2ASP - Phil Kane Life Member - Society of Broadcast Engineers 73, Len AF6AY Life Member - Institute of Electrical and Electronic Engineers No pixels were harmed in the generation of this message but billions of electrons were rudely shoved around. |
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