Good points, Don. Last night, I experimented using DM780 (the datamodes program in the HRD suite) to visualise the audio rather than using Spectogram. I found that the waterfall made it much easier to see the "shape" of the filters. I don't have a noise generator so I'm using band noise. The randomness makes it quite difficult to see the shape in Spectogram; particularly at low audio; whereas a waterfall is more defined.
I'll return to the setting up of the filters at the weekend and report back. Incidentally, using the waterfall exposed that I hadn't actually set the VCO calibration as I originally thought. As I said earlier, I actually tuned off WWV by 600Hz. Now I'm using a waterfall I can see that I was actually tuning the 100Hz timecode subcarrier. Gareth, M5KVK Sent from my iPad > On 26 Feb 2015, at 14:01, Don Wilhelm <[email protected]> wrote: > > Gareth, > > Good work. May I offer a couple suggestions: > 1) On SSB filters other than the FL1 OP1 filter, look carefully at the actual > filter width. On many K2s, the actual width is far wider than that indicated > by the K2 display. You ideally want to have each filter progression about > 200 to 300 Hz more narrow then the prior filter. The easiest way to set that > up is to first do LSB - the low frequency slope of the passband will not move > substantially as you adjust the width. The set the BFOs for the filters > after adjusting00 the width. > > 2) Rather than using SSB FL4 for PSK and other data modes, turn on RTTY in > the secondary menu. That gives you another set of filters and an independent > compression setting from SSB and you don't have to remember to turn > compression off when using data modes. I normally set RTTY FL1 the same as > SSB FL1 (including the BFO settings - RTTY is LSB and RTTY rev is USB) and > then set the FL2 to 1000 Hz, FL3 to 700 Hz and FL4 to 400 Hz widths. I > center those 3 filters on 1000 Hz. If you are not able to properly center > the 400 Hz wide filter, you will have to pad the BFO with a small value > capacitor (try 15 to 22pF) between pins 6 and 3 of RF board U11 - then > recheck the BFO range. If you do have to make that change, you will need to > re-do all the BFO alignments. > > 73, > Don W3FPR > >> On 2/26/2015 8:29 AM, Gareth - M5KVK wrote: >> Having finally got my KSB2 board working (it was a hi-resistance solder >> joint: enough to depress performance but not stop all signals), and >> calibrated the dial, I turned to setting up the filters. >> >> I started with the filter widths and BFO settings in the KSB2 manual, but it >> didn't sound right. So I decided to use WWV and Spectrogram. >> >> Now that I knew that the VFO was OK, I set it to 10000.00. No audio on LSB >> or USB, which is good. >> I then tuned off by 600Hz to create a steady signal at 10000.60kHz >> (9999.40kHz on the other sideband) and displayed the audio on spectrogram >> with a 600Hz marker set. >> I then went through CAL FIL, adjusting the BFO so that the audio tone was >> exactly 600Hz. >> >> I did this on all modes and filter widths: except FL4 on LSB and USB, which >> I adjusted for a 1000Hz centre (so I can use them for PSK31). >> >> I was surprised how far off the displayed spectrum was with the factory >> settings. On USB FL4, the centre was at 400Hz with the manual’s suggested >> BFO setting. >> >> 73, Gareth M5KVK > ______________________________________________________________ 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 Message delivered to [email protected]
