Re: [Elecraft] K2 Crystal Filter Alignment Questions
Don, Thanks very much for the response. I actually did get up to speed on Spectrogram, and I'm very happy with the results. Now, the CW signal remains stationary in pitch, and jumps out at me as I invoke successively tighter filters. Spectrogram is also fun! The problem that previously prevented me from using Spectrogram was that I didn't know that getting the K2's audio into the PC was as simple as running a cable from the K2's headphone jack to the PC's microphone jack. Instead, I envisioned having to have an interface circuit of some kind and wire up a USB connector. As a side benefit, now that I have receiver audio going into my computer, my next project is to figure out how to decode PSK-31 signals. Cool stuff! 73, Jeff WB5GWB - Original Message - From: Don Wilhelm [EMAIL PROTECTED] To: Bill Coleman [EMAIL PROTECTED]; Jeff [EMAIL PROTECTED] Cc: elecraft@mailman.qth.net Sent: Sunday, September 17, 2006 12:06 AM Subject: RE: [Elecraft] K2 Crystal Filter Alignment Questions Jeff, Let me add my 2 cents worth: First, if you have been attempting to align your filters by trial and error, you may have the wrong sideband set. Secondly, a shift of 20 Hz or so is to be expected because of the DAC resolution - if your shift is any more than 20 Hz, it can be corrected by proper filter adjustment. Third, I don't understand why you are shying away from Spectrogram - it is by far the easiest method of correctly setting the filter passbands. Forth, If you have been arbitrarily moving the BDO settings 'by ear', it is quite possible that you have the BFOs set to the wrong sideband. A good starting point is the settings in the manual (either the K2 manual or the KSB2 manual. Shift the sideband as required from these settings, but do not go too far - going far from those values will result in the BFO being set to the incorrect sideband. I strongly suggest that you download Spectrogram and use that to set your filters - see the note from Tom Hammond. Tom's websote contains the last freeware version of Spectrogram and instructions for setting it up and using it to align the K2 filters - try it, I assure you that you will not be disappointed in the results. 73, Don W3FPR ___ 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
RE: [Elecraft] K2 Crystal Filter Alignment Questions
Just a note: For those who do not have a serial port available and wish to use a USB to Serial to converter (for PTT purposes, etc.), the Belkin F5U409 model works terrifically well. It supports the entire RS232 protocol (not all converters do) and has LINK, TX, RX indicator LEDS. 73, Bill Allen WA5PB -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Don Wilhelm Sent: Sunday, September 17, 2006 2:08 PM To: Jeff; [EMAIL PROTECTED] Cc: elecraft@mailman.qth.net Subject: RE: [Elecraft] K2 Crystal Filter Alignment Questions Jeff, If what you want to do right now is just receive PSK31 signals, use the same cable connection that you used for Spectrogram and run one of the PSK31 programs on your PC (DigiPan and Ham Radio Deluxe are 2 popular freeware programs - yes there are others). You may have better luck with the K2 external speaker jack and the soundcard line-in jacks than the headphone jack and the mic input, but try them both and see what works. Transmitting gets a bit more complex, but you only need to connect the soundcard line out to the K2 mic AF input - because the soundcard output is much greater than the mic input, you will need a resistive divider. Also at this point, you should consider isolating the lines between the computer and the K2 - I use transformers salvaged from defunct modems successfully. While you can change from receive to transmit by manually keying the transceiver after clicking the mouse, as a further step add automatic control of the PTT line. Add an optoisolator to connect the RTS and signal ground from a computer serial port and drive the K2 PTT line from the output of the optoisolator. You could use a simple transistor instead of the optoisolator, but the transistor does not allow ground isolation, and you could encounter RF feedback being picked up on the computer chassis and grounding system, etc., but for simplicity, it is worth a try. If you are stuck with no serial ports on your computer, a USB to Serial adapter could be used ahead of the PTT keying circuit. That is all there is to any PSK31 interface - some of the boxes available include microphone switching, and audio output switching, but those are add-on conveniences, the simple interface that I described (2 lines from the computer preferrably with transformers and an optoisolator for the PTT activation) is all that is needed for a full interface function, and can be built for less than $10 if you scrounge the transformers and don't have to pay much for an enclosure and jacks. 73, Don W3FPR -Original Message- The problem that previously prevented me from using Spectrogram was that I didn't know that getting the K2's audio into the PC was as simple as running a cable from the K2's headphone jack to the PC's microphone jack. Instead, I envisioned having to have an interface circuit of some kind and wire up a USB connector. As a side benefit, now that I have receiver audio going into my computer, my next project is to figure out how to decode PSK-31 signals. Cool stuff! 73, Jeff WB5GWB ___ 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 -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.405 / Virus Database: 268.12.4/449 - Release Date: 9/15/2006 ___ 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
RE: [Elecraft] K2 Crystal Filter Alignment Questions (now PSK31 interface)
Bill, Good info, but if the purpose is only for PSK31 PTT keying, most any adapter should do the job because it needs only RTS and signal ground, and I can't imagine any USB to serial adapter that would not include those essential signals. I got one that works for $3.99 at TigerDirect. 73, Don W3FPR -Original Message- Just a note: For those who do not have a serial port available and wish to use a USB to Serial to converter (for PTT purposes, etc.), the Belkin F5U409 model works terrifically well. It supports the entire RS232 protocol (not all converters do) and has LINK, TX, RX indicator LEDS. 73, Bill Allen WA5PB ___ 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
RE: [Elecraft] K2 Crystal Filter Alignment Questions
Jeff, Let me add my 2 cents worth: First, if you have been attempting to align your filters by trial and error, you may have the wrong sideband set. Secondly, a shift of 20 Hz or so is to be expected because of the DAC resolution - if your shift is any more than 20 Hz, it can be corrected by proper filter adjustment. Third, I don't understand why you are shying away from Spectrogram - it is by far the easiest method of correctly setting the filter passbands. Forth, If you have been arbitrarily moving the BDO settings 'by ear', it is quite possible that you have the BFOs set to the wrong sideband. A good starting point is the settings in the manual (either the K2 manual or the KSB2 manual. Shift the sideband as required from these settings, but do not go too far - going far from those values will result in the BFO being set to the incorrect sideband. I strongly suggest that you download Spectrogram and use that to set your filters - see the note from Tom Hammond. Tom's websote contains the last freeware version of Spectrogram and instructions for setting it up and using it to align the K2 filters - try it, I assure you that you will not be disappointed in the results. 73, Don W3FPR -Original Message- On Aug 19, 2006, at 1:52 AM, Jeff wrote: Should the pitch of the background atmospheric noise change when CW RV is toggled on and off? If you get it adjusted right, the pitch shouldn't change (or should change very little), however the color of the noise might shift a bit, depending on the bandwidth, due to a bit of asymmetry in the bandpass of the filter. Also, I have the KSB2 installed, and the pitch of the atmospheric noise changes greatly when I switch from USB to LSB or vice versa. You don't have it adjusted right. The pitch should change very little, the color will change a bit because of the asymmetry of the filter, but if you get it adjusted correctly you'd hardly notice the shift. Finally, and most irritatingly of all, in CW mode, when I switch from filter FL1 to FL2, the pitch of the received CW signal changes significantly. However, when I switch from FL2 to FL3, or from FL3 to FL4, no such pitch change occurs, which is good. The K2 design isn't perfect in this regard, because of the way the BFO frequencies are determined - but you should be able to get any shift down to a few Hz, if that. It sounds to me like you don't quite have the filters aligned correctly. I assume that I inadvertently changed the FL1 BFO setting. However, I subsequently tried various settings and couldn't get the pitch of the received CW note for FL1 to match that of FL2. Again, because of the quantization of the BFO frequency, you may not be able to get all the filters perfectly aligned on the same frequency. Close is good. Shouldn't I be able to correct this problem by trial-and-error, without using Spectrogram? Yes, I've done this. Try moving a filter one step up or down from where Spectrogram thinks it should be. See if it makes things better or worse. Unfortunately, I'm not set up to use Spectrogram to align the filters. If you can't use Spectrogram, perhaps you can use another piece of software that supports and audio spectrum display. This is really the best way to align the K2 filters. (I personally use CocoaModem (a MacOS X RTTY / PSK application) to align my K2) p.s. Here's a trivia question to which I'm curious to know the answer: Why is it that the KAT2's relays chatter pleasantly when you turn the K2 on, but make not a peep when you turn it off? Latching relays. They remember their last state and stay there even if no power is supplied. Bill Coleman, AA4LR, PP-ASELMail: [EMAIL PROTECTED] Quote: Not within a thousand years will man ever fly! -- Wilbur Wright, 1901 ___ 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 -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.405 / Virus Database: 268.12.3/445 - Release Date: 9/11/2006 ___ 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
Re: [Elecraft] K2 Crystal Filter Alignment Questions
On Aug 19, 2006, at 1:52 AM, Jeff wrote: Finally, and most irritatingly of all, in CW mode, when I switch from filter FL1 to FL2, the pitch of the received CW signal changes significantly. However, when I switch from FL2 to FL3, or from FL3 to FL4, no such pitch change occurs, which is good. The K2 design isn't perfect in this regard, because of the way the BFO frequencies are determined - but you should be able to get any shift down to a few Hz, if that. It sounds to me like you don't quite have the filters aligned correctly. My guess is that IF the CW note changes SIGNIFICANTLY between FL1 and FL2, then you probably have the BFO setting on the WRONG SIDE of filter-center. This is not an uncommon problem. Fortunately, it is one which can be easily fixed... especially if you are using Spectrogram and IF you follow the published instructions, BOTH of which are available FOR FREE at www.n0ss.net. The important thing is to know which sideband (CW NOR or CW REV) you're aligning, and then ensuring that the BFO is always positioned to the proper sideband (either above or below the center frequency of the filter). Shouldn't I be able to correct this problem by trial-and-error, without using Spectrogram? Yes, I've done this. Try moving a filter one step up or down from where Spectrogram thinks it should be. See if it makes things better or worse. It CAN be corrected by trial error, but it's a WHALE OF A LOT EASIER if you do use Spectrogram. Unfortunately, I'm not set up to use Spectrogram to align the filters. What are the problems to setting up TO use it? 73, Tom Hammond N0SS ___ 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
Re: [Elecraft] K2 Crystal Filter Alignment Questions
On Aug 19, 2006, at 1:52 AM, Jeff wrote: Should the pitch of the background atmospheric noise change when CW RV is toggled on and off? If you get it adjusted right, the pitch shouldn't change (or should change very little), however the color of the noise might shift a bit, depending on the bandwidth, due to a bit of asymmetry in the bandpass of the filter. Also, I have the KSB2 installed, and the pitch of the atmospheric noise changes greatly when I switch from USB to LSB or vice versa. You don't have it adjusted right. The pitch should change very little, the color will change a bit because of the asymmetry of the filter, but if you get it adjusted correctly you'd hardly notice the shift. Finally, and most irritatingly of all, in CW mode, when I switch from filter FL1 to FL2, the pitch of the received CW signal changes significantly. However, when I switch from FL2 to FL3, or from FL3 to FL4, no such pitch change occurs, which is good. The K2 design isn't perfect in this regard, because of the way the BFO frequencies are determined - but you should be able to get any shift down to a few Hz, if that. It sounds to me like you don't quite have the filters aligned correctly. I assume that I inadvertently changed the FL1 BFO setting. However, I subsequently tried various settings and couldn't get the pitch of the received CW note for FL1 to match that of FL2. Again, because of the quantization of the BFO frequency, you may not be able to get all the filters perfectly aligned on the same frequency. Close is good. Shouldn't I be able to correct this problem by trial-and-error, without using Spectrogram? Yes, I've done this. Try moving a filter one step up or down from where Spectrogram thinks it should be. See if it makes things better or worse. Unfortunately, I'm not set up to use Spectrogram to align the filters. If you can't use Spectrogram, perhaps you can use another piece of software that supports and audio spectrum display. This is really the best way to align the K2 filters. (I personally use CocoaModem (a MacOS X RTTY / PSK application) to align my K2) p.s. Here's a trivia question to which I'm curious to know the answer: Why is it that the KAT2's relays chatter pleasantly when you turn the K2 on, but make not a peep when you turn it off? Latching relays. They remember their last state and stay there even if no power is supplied. Bill Coleman, AA4LR, PP-ASELMail: [EMAIL PROTECTED] Quote: Not within a thousand years will man ever fly! -- Wilbur Wright, 1901 ___ 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
