> I am not using such an elaborate sound system, just > running the headphones direct into the rig. Speakers are > SP 20 Icom and the other is a Ten Tec 307B. Using this > method of plugging the headphones into the pnones jack, > and using the speaker in put on the rig for output, there > is definitely an audio problem when going from phones to > speaker which requires and adjustment of the sidetone. > Another way around this is to have an MFJ 784B tunable > filter and use it for both both phones and speakers. > This way the volume comtrol on the MFJ unit will equalize > all audio and it will work the way I would like it to.
Hi Toby, Because I use stereo diversity, I also have a set of 784 DSP filters in stereo. The frequency and passband controls in one adjust both. I used them primarily with my stereo modified R4C's, so the DSP filters follow my heavily modified R4C's around. Whether I use the 784's or not, I still mix left and right ears into mono because I only have a single speaker. This led me to discover an interesting phase effect combining two receivers into one channel when the receivers shared the same oscillators. When using two antennas that have wide spatial separation, and by changing phase lag or lead between the two channels (either at RF or at audio), a signal can be totally nulled out or directly added. I had a calibration chart for my antennas. I measured audio phase difference between the channels, and by using antennas several hundred feet apart I could resolve a difference in direction of a few degrees. It was easy to resolve the difference between eastern and western Massachusetts from here in Georgia. I found this very useful for locating jammers, spurious signals from BC transmitters, or just nulling unwanted CW signals out while still hearing other much weaker signals on the very same frequency. DF'ing unfortunately does not work with the K3 because the channels rotate phase in relationship to each other as dial frequency is changed, so DF'ing is out of the question. Nulling signals will work, but maintaining directional calibration is impossible. Someday someone smarter than me will do this in firmware, where the two receivers in the K3 can be used to null a CW signal while still passing a weaker signal on the very same frequency. Another interesting effect is nulling one's own transmitter, although for maximum dynamic range it has to be done at radio frequencies. Even with limited dynamic range it is possible to hear stronger signals while the key is depressed. The ultimate in QSK. If done properly at radio frequencies, it even works on SSB. I can hear stronger SSB stations while I am transmitting on the very same frequency. My own transmitter is S-9 or so, so I can hear anyone stronger than S-9 on my own frequency while I am transmitting. There are many things that can be done with two identical receiver channels, or with RF phasing. :-) 73 Tom ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
