In a message dated 5/27/06 9:05:26 PM Eastern Daylight Time, [EMAIL PROTECTED] writes:
> It implies transmitting without listening first on the xmit > frequency to be sure it is clear, an absolute *must do* for proper Ham > operation. I don't see where it implies that any more than split operation or RIT operation does. > > When I need to xmit off frequency I tune to the intended xmit freq and, > hearing it's clear, hit A/B to put myself back listening on the original > frequency, all set to xmit off frequency as needed when I hit the key with > SPLIT enabled. If it's been a while since I checked, all I need do is > press/hold A/B to 'peek' at the other frequency to be sure it's still clear. > Of course! But with XIT, all someone has to do is turn on RIT and they're listening on the transmit frequency. > I run split 100% of the time. I tune around and if I hear someone I want to > call (or find a clear frequency on which I want to make a call) I just tap > A=B and that brings the transmit frequency onto the frequency where I'm > receiving. Then if someone answers my call a bit off frequency, it's a > no-brainer. I just tune - using the nice big tuning knob - as needed without > altering my xmit frequency. Nothing wrong with that if it works for you. I've never used XIT because a situation where it was needed hasn't arisen in my operating. I use RIT frequently because it's more convenient for me. Perhaps this is a result of contest operating experience. Most of my contesting has been hunt-and-pounce operating, and if I had to hit A=B for every station I called that's a lot of pushes! -- Someone asked where all this RIT and XIT stuff came from in the first place. Here's my theory/history: Until the late 1950s, most HF ham operation was with separate transmitters and receivers, requiring a lot of zero beating in typical operation. Those "separates" had a lot of features and a lot of controls. Then came SSB transceivers like the KWM-2, plus matched-pair receivers and transmitters like the S-line. The new SSB transceivers turned things upside down in many ways. One of the major disadvantages of SSB operation with separate tx/rx was the need for very accurate zerobeating, particularly in roundtable operation. Transceivers eliminated that task. Because a filter-type SSB transceiver used many components for both tx and rx, (particularly expensive components like oscillators and filters), its cost, size and complexity were less than separate tx/rx. By the early 1960s, a 100 watt class SSB transceiver could be sold for less than a 100 watt AM station. And because those first-generation transceivers were one-box stations optimized for one mode, they had relatively few controls and features. Look at the front panel of a KWM-2 - fewer controls than most *receivers* of that era. But those first-generation SSB transceivers had their limitations. One problem with some of them was less than perfect stability. Another was lack of provision to deal with differences in how some folks would tune in another's signal. If one station in a QSO moved frequency, or wasn't exactly zeroed for any reason, and the other retuned to maintain intelligibility, and then the first retuned to keep up with the second, they'd wind up waltzing across the band. One solution was a second VFO. But that was an expensive option and brought back the zeroing problem. Plus with analog VFOs, the only way to implement "A=B" was to spin the knob. So 'RIT' or 'clarifier' controls were added to the main VFO, at much less cost and complexity. All this took a while - it wasn't until the mid-late 1970s that RIT and provision for an external 2nd VFO were pretty much standard on HF transceivers. Once you had RIT, XIT was really just a matter of switching. Then came the change from analog to digital VFOs, about 20 years ago. Frequency control became a matter of telling the synthesizer the QRG. Multiple VFOs, RIT, XIT, memories and other features became a matter of programming the controller and figuring out the hardware interface. With such flexibility, rig makers weren't going to leave features like RIT and XIT out even though they'd started out as ways to avoid the expense and complexity of a second VFO. IIRC, Ten Tec produced the Omni V without a separate RIT/XIT knob. When you turned on RIT, the main tuning knob became the RIT/XIT knob. But the complaints were such that the Omni VI had a separate RIT/XIT knob. So we've come full circle. Most current HF transceivers have lots of features and lots of controls - many of which most hams rarely or never use. Ironically, the Cosmophone 35, arguably the first true amateur HF SSB transceiver, didn't have RIT. But it did have "dual VFOs" - actually two tuned circuits, switched by a relay inside the VFO. And it had a lot of controls and a big, human-sized front panel. Perhaps that circle will finally come around. 73 de Jim, N2EY _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
