John, NA8M wrote: ...the MD2 sounded bad on frequency, but sounded normal if I tuned up about 40 hz. The Ten Tec had no lows and changing frequency made little difference. But, it took more voice to trip the VOX with the Ten Tec.
Would this be due to my filter setup? Will adjusting the OP1 filter bring my transmit frequency back? Do I need to move the filter up or down? Will changing KSB2 R14 from 1k to 2-3K help the Ten Tec mike drive the KSB2? All help greatly appreciated. --------------------------------------- Regarding audio quality: 1) Are you properly tuned into your own signal when monitoring? Depending upon how you've calibrated your K2, your frequency reading may not be the exact frequency, so it's normal to tune for best sound. Also, is XIT turned off? If your rig is more than 10 or 20 Hz off frequency, you can improve the dial accuracy by properly calibrating the master clock on the Control Board. See the instructions for calibrating C22 on the Elecraft site under Builder's resources. Even when calibrated, a dial error of up to about 30 Hz is common, because of the resolution of the logic circuits used. 2) What filter bandwidth are using for OPT1? It is fixed, but can be changed by changing components on the SSB board. The basic K2 SSB module has a filter bandwidth of just about 2 kHz. That's 'tight' for most SSB operators. It can sound good and, most importantly, has the greatest "punch" when set up just right (tighter bandwidth concentrates the RF in a smaller slice of spectrum). But its adjustment is very touchy. Many SSB operators prefer to use the mod kit available from Elecraft to widen the SSB filter out more like other rigs for better overall sound and ease of adjustment. 3) How did you set up your BFO frequencies (CAL FIL)? It has been my experience that using Spectrogram is simply not good enough to know that the setting is optimal. As the SSB manual says, it takes listening to your own signal to make the final "tweaks" of the BFO settings in most cases. This is especially true when using the 'stock' narrower filter. A little experimenting while listening to your own signal will quickly show you which direction to move the BFO frequencies. 4) How old is your SSB module? Some of the very early modules had crystals that were even tighter than the current crop. Some produced bandwidths well under 2kHz and it was simply impossible to set up the SSB board for good audio. That issue was addressed several years ago, but if you have an early board that you are only now putting to work on SSB, that might be the case. Spectrogram will show you the overall filter bandwidth. Regarding drive level: Are you seeing ALC action on all bands? Press and hold DISPLAY RF/ALC to switch between RF output and ALC action. The bar graph reads backwards (right-to-left) in ALC mode. If even one bar of ALC is flickering, you have plenty of drive from the mic - enough that the K2 is automatically reducing the gain to prevent over-driving. If not, then raising the value of R14 can help. There are other possible mods to increase the drive shown on the Elecraft web site. Ron AC7AC _______________________________________________ Elecraft mailing list Post to: [email protected] 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
