-----Original Message----- Matt wrote: I'm a little confused about measured transmitted power when in SSB vs CW.
As an example, I have an XV50 Transverter that is adjusted to produce 20 watts RF out when using the K2 'tune' control. This output is adjusted by reading 20 watts on an external power meter. The power indicator LEDs are then adjusted to read 20 watts as well. When using SSB, however, the RF out is much, much lower, maxing out at 7-8 watts PEP on the external power meter. The indicator LEDs, however, indicate 10 - 20 watts of power. I'm not certain I know how to understand what it is I'm measuring. In my mind, I think much the 20 watts RF out of a CW signal is actually carrier and of not much use. When in SSB, I want to think that I can still put out the 20 watts, only now all concentrated in one sideband. Why does the power meter fail to show the 20 watts? _______________________________________________ Of course CW is ONLY carrier, on and off, so the information is in the keying. But when the key is down, you are putting out full power. Your transverter should be configured to put 20 watts out when driven at either 5 watts or 1 mW, key down in CW mode, depending upon whether you have the K60XV interface installed in your K2 and are using the RF output at the antenna connector or the K60XV connection. When your K2 is in TUNE, the power is reduced and no longer controlled by the K2's automatic power controlling system. That's so you can tune up with an ATU and the K2 won't go nuts trying to adjust its power output as the SWR changes. If you set up your transverter for 20 watts output with the K2 in TUNE, you may overdrive it in normal operation. SSB has a very low duty cycle. That is, the average power output is far, far below the peaks. You can raise the average power a bit using the K2's speech compression, but its average is still well below the peak CW level. The very brief transient peaks in your voice will hit full 20 watts out and unless your Power meter is designed to register peak RF and not average RF (like most meters) it'll show a much, much lower RF AVERAGE output even though your voice peaks are hitting 20 watts. The LED display on the transverter (and K2's RF bargraph) show the actual output, so you'll see them both flicker on voice peaks. Ron AC7AC _______________________________________________ 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
