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#1
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Example.
A few months ago a group of ham radio operators went into the central Pacific Ocean to an island named Swain's Island [ATOLL]. Swain's Island had just been approved by the Ham radio Certificate Powers {American Radio relay League] as a separate DX [distance] entity and as such it qualifies as an entry into the various DX awards [DXCC being the prime award}. [DXCC means you have submitted written proof of confirmed contacts with other ham radio operators in 100 or more other countries [or entities]. The Hams operated from this rare location for about a week and then returned home. There is no-one there today! Let me digress into another of your questions: i.e. What is SSB? Fifty years ago ham radio, and still today the AM broadcast band, transmitted three components to put a signal on the air. First, was the carrier that set the dial frequency e.g. 3950 KHz. The carrier contains NO information, it just sets the dial frequency. Then voice audio was added to the carrier. This addition [modulation] produced two audio signals around the carrier. One above the carrier, the other below the carrier. So, the resulting signal had the carrier and one upper side band and one lower sideband. The carrier contained 2X the power of the audio. And the audio was redundant with 1/2 the audio power in each sideband. The resulting signal can be described as Double Sideband Plus Carrier. In the 50s and early 60s design techniques were incorporated to suppress the carrier, which contained NO information; and to eliminate one of the redundant sidebands. The resulting signal is Single Sideband [one audio channel] with suppressed carrier. [SSB = Single Side Band] wrote: On Wed, 30 Aug 2006 18:10:03 +0200 (CEST), Anonymous via the Cypherpunks Tonga Remailer wrote: Dave Said: As long a 'Rare DX' uses CW, CW will live and thrive in the DX community. I've seen this DX term here and there, but, can't seem to find out what it stand for, or what a DX community is. Can you post some info or links on what this is/involves? well even if you are pulling our chain it is better than a lot of the stuff posted DX isseeking out Distant contacts for an eXchange of very basic data and ocollecting these conacts and esp proof of these conacts for various awadrd the DX comunity obviously is those into chasing down these DX contacts Thanks, noonespecial http://kb9rqz.blogspot.com/ |
#2
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Dave wrote:
Example. A few months ago a group of ham radio operators went into the central Pacific Ocean to an island named Swain's Island [ATOLL]. It was just last month, Dave. Swain's Island had just been approved by the Ham radio Certificate Powers {American Radio relay League] as a separate DX [distance] entity and as such it qualifies as an entry into the various DX awards [DXCC being the prime award}. [DXCC means you have submitted written proof of confirmed contacts with other ham radio operators in 100 or more other countries [or entities]. The "Ham radio Certificate Powers"? The Hams operated from this rare location for about a week and then returned home. There is no-one there today! Really? The people who live there just up and left? Let me digress into another of your questions: i.e. What is SSB? Fifty years ago ham radio, and still today the AM broadcast band, transmitted three components to put a signal on the air. First, was the carrier that set the dial frequency e.g. 3950 KHz. The carrier contains NO information, it just sets the dial frequency. The carrier is just there for setting a dial frequency? How about if one just transmitted ONE component, the carrier and then turned it on and off and regular intervals. It might be possible to use the on/off pulses to convey information, huh? In the 50s and early 60s design techniques were incorporated to suppress the carrier, which contained NO information; and to eliminate one of the redundant sidebands. The resulting signal is Single Sideband [one audio channel] with suppressed carrier. [SSB = Single Side Band] Those "design techniques" were used as early as about 1927. Where is all this going? Dave K8MN |
#3
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I would like to add that DXing isn't limited to chasing awards. Some people
just like to find someone in a foreign country to ragchew with. One day I was lucky enough to come across a gentleman in Italy who simply wanted to talk not run a pileup. We spent about 1/2 an hour just chatting. Dee D. Flint, N8UZE "Dave" wrote in message . .. Example. A few months ago a group of ham radio operators went into the central Pacific Ocean to an island named Swain's Island [ATOLL]. Swain's Island had just been approved by the Ham radio Certificate Powers {American Radio relay League] as a separate DX [distance] entity and as such it qualifies as an entry into the various DX awards [DXCC being the prime award}. [DXCC means you have submitted written proof of confirmed contacts with other ham radio operators in 100 or more other countries [or entities]. The Hams operated from this rare location for about a week and then returned home. There is no-one there today! Let me digress into another of your questions: i.e. What is SSB? Fifty years ago ham radio, and still today the AM broadcast band, transmitted three components to put a signal on the air. First, was the carrier that set the dial frequency e.g. 3950 KHz. The carrier contains NO information, it just sets the dial frequency. Then voice audio was added to the carrier. This addition [modulation] produced two audio signals around the carrier. One above the carrier, the other below the carrier. So, the resulting signal had the carrier and one upper side band and one lower sideband. The carrier contained 2X the power of the audio. And the audio was redundant with 1/2 the audio power in each sideband. The resulting signal can be described as Double Sideband Plus Carrier. In the 50s and early 60s design techniques were incorporated to suppress the carrier, which contained NO information; and to eliminate one of the redundant sidebands. The resulting signal is Single Sideband [one audio channel] with suppressed carrier. [SSB = Single Side Band] wrote: On Wed, 30 Aug 2006 18:10:03 +0200 (CEST), Anonymous via the Cypherpunks Tonga Remailer wrote: Dave Said: As long a 'Rare DX' uses CW, CW will live and thrive in the DX community. I've seen this DX term here and there, but, can't seem to find out what it stand for, or what a DX community is. Can you post some info or links on what this is/involves? well even if you are pulling our chain it is better than a lot of the stuff posted DX isseeking out Distant contacts for an eXchange of very basic data and ocollecting these conacts and esp proof of these conacts for various awadrd the DX comunity obviously is those into chasing down these DX contacts Thanks, noonespecial http://kb9rqz.blogspot.com/ |
#4
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From: Dave on Wed, Aug 30 2006 10:34 am
Let me digress into another of your questions: i.e. What is SSB? Fifty years ago ham radio, and still today the AM broadcast band, transmitted three components to put a signal on the air. First, was the carrier that set the dial frequency e.g. 3950 KHz. The carrier contains NO information, it just sets the dial frequency. Then voice audio was added to the carrier. This addition [modulation] produced two audio signals around the carrier. One above the carrier, the other below the carrier. So, the resulting signal had the carrier and one upper side band and one lower sideband. The carrier contained 2X the power of the audio. And the audio was redundant with 1/2 the audio power in each sideband. The resulting signal can be described as Double Sideband Plus Carrier. In the 50s and early 60s design techniques were incorporated to suppress the carrier, which contained NO information; and to eliminate one of the redundant sidebands. The resulting signal is Single Sideband [one audio channel] with suppressed carrier. [SSB = Single Side Band] "Dave," your knowledge of Single Sideband is ferklempt. The spectra of an amplitude modulated signal was mathematically described by John R. Carson of AT&T before the 1920s. SSB, including suppressed carrier, was USED by the telephone infrastructure in the 1920s for long-distance lines. The most common system, "C Carrier," had four separate 3 KHz voice channels and would operate on the open-wire telephone lines then common all over the world. This "C Carrier" was directly adapted to HF radio in the early 1930s, the frequency-multiplexed total signal converted to HF and amplified. The first HF SSB radio link was put into service between the Netherlands and the Netherlands Antilles carrying four voice channels or (to become the later commercial-military standard of two voice and six to eight TTY channels). While single-channel SSB was experimented with before WW2, it didn't expand until after WW2 and a number of US military contracts awarded to then-prominent radio makers (Collins, RCA as two examples). Based on that success, the amateurs took it up in the 1950s while the ARRL promoted the false idea that "SSB was pioneered by radio amateurs." Technically, your statement was faulty. Each "sideband" (the spectra adjacent to the carrier) carries ONE QUARTER of the total RF power output of single-channel SSB, not "half" in normal AM. In normal AM the carrier is always constant in amplitude. In normal AM receivers the "detector" stage is a mixer, combining the carrier with the two sideband spectra with the output lowpass filtered to yield the original audio signal. Single-channel SSB usually suppresses the carrier (almost to extinction) and the "detector" stage being fed an equivalent constant-amplitude carrier signal from an internal receiver oscillator. The mix products of carrier re-insertion and the input single sideband spectra yield the original audio modulation after lowpass filtering. The important thing about single-channel SSB is that a transmitter peak power output of RF need only be one-half to on-quarter of a conventional AM transmitter to yield the same demodulated audio signal level. No morsemanship skill is necessary to use a single-channel SSB radio. Today it is being used on the open sea by both commercial and private boat/ship owners for voice communications; also data, separate or multiplexed, for written communications. |
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