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ucwlcw [2007/04/30 18:31] n5na created |
ucwlcw [2007/05/21 00:45] (current) |
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| DE N6KB | DE N6KB | ||
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| + | **October 27, 2006** | ||
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| + | When you go to LCW or UCW, the receiver is offset by the frequency of the "spot" frequency. Some times I have to check into the Badger Weather Net on 3985 on CW even though it is SSB. When I change from LSB to LCW and open the filter, I have to tune down 700 Hz to 3984.3 to copy the SSB. I then turn on the XIT and set it to -700 so they can copy my note. Otherwise I will be on 3985 and not create a tone in their receiver. Try it sometime. | ||
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| + | 73, | ||
| + | John W3GQJ | ||
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| + | **October 27, 2006** | ||
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| + | This feature of modern rigs further confuses the issue. In SSB service, the dial (or digital) frequency readout indicates the frequency of a carrier that would be zero beat. Signals either side of that will produce beat notes of greater than zero frequency. (apparently however the guvmint has decided to use the center of the "channel" passband instead of the zero beat frequency to designate the frequency of an SSB channel, ala 60 meters). | ||
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| + | Most of us do not listen to CW signals with the receiver set to have them at zero beat, preferring an audio note with a frequency greater than zero. In order to set our transmitter frequency to the same frequency as the other station we want to work, it must be some amount (several hundred Hertz) away from the zero beat frequency. In fact if we want the be exactly on the other guys frequency, our transmit frequency must be offset the same amount and the same direction as the other guy is from our receiver's zero beat. In a good transceiver the "sidetone" generated by the rig when you key it, will be the same as the note you need to tune the other guys signal to, in order to get your transmit frequency right on his. It makes sense to have the frequency readout indicate where our transmitted signal will be (so we stay inside the band limits) rather than where a zero beat received signal is. Yet this can cause some confusion. | ||
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| + | With separate transmitter and receiver, you just turn the TX VFO (in the spot mode) until you hear the same note as the signal you are listening to, and your receiver provides a sidetone. The transmitter does not have to generate an audio tone for you to hear your sending. In this system you can transmit on the opposite sideband, getting the same audio note, yet not being on the same frequency as the station you are calling. | ||
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| + | It's all relative. | ||
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| + | DE N6KB | ||
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| + | **October 29, 2006** | ||
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| + | The Orion "dial" frequency is the center of the passband for LCW or UCW if PBT=0. An incoming signal at that freq. produces a tone at the sidetone/spot freq., e.g., 700 Hz. The difference between LCW and UCW is what happens when you tune off frequency, say up by 100 Hz. For LCW, the audio tone will go up (like tuning an LSB voice signal). For UCW, the tone goes down (like USB voice). | ||
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| + | I have never seen the need for both LCW and UCW. I always use LCW myself. Just personal preference. | ||
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| + | 73 Martin AA6E | ||
