Re: [Elecraft] Tight Skirts...
On Mar 4, 2005, at 1:20 AM, Eric Swartz WA6HHQ - Elecraft wrote: OP1 is the KSB2's SSB fixed b/w filter, which has been optimized for minimum ripple at one SSB b/w. In SSB it is always used for transmit, but it or any of the CW filter bandwidths can be used for receive. Here's an interesting question -- what are OP2-5 for? I spent a while studying the schematic trying to figure out if these selections also activated some other I/O lines in the KSB2 controller. None that I could find. 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
Re: [Elecraft] Tight Skirts
You fared better than I did Tim. I had a '76 Europa Twin Cam, the black JPS job with gold pinstripes. Eventually sold it for lack of garage space... my wife was happy, my son hated me ;-) I loved scaring people by taking corners at speeds they thought were impossible. Still married after 28 years though... she likes ham radio ;-) Larry N8LP Tim O'Rourke wrote: In 70's tight short skirts were popular. I drove a Lotus and enjoyed the view watching dates slide in and out of the Europa. BTW still have car and girl friend is my wife for last 33 years. Tim W4YN Tim O'Rourke [EMAIL PROTECTED] ___ 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 . ___ 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] Tight Skirts
My MGB wasn't quite as sexy but served the same purpose..the YL has been my XYL for the last 40 years. Doug W6JD - Original Message - From: Larry Phipps [EMAIL PROTECTED] To: Tim O'Rourke [EMAIL PROTECTED] Cc: elecraft@mailman.qth.net Sent: Saturday, March 05, 2005 7:53 AM Subject: Re: [Elecraft] Tight Skirts You fared better than I did Tim. I had a '76 Europa Twin Cam, the black JPS job with gold pinstripes. Eventually sold it for lack of garage space... my wife was happy, my son hated me ;-) I loved scaring people by taking corners at speeds they thought were impossible. Still married after 28 years though... she likes ham radio ;-) Larry N8LP Tim O'Rourke wrote: In 70's tight short skirts were popular. I drove a Lotus and enjoyed the view watching dates slide in and out of the Europa. BTW still have car and girl friend is my wife for last 33 years. Tim W4YN Tim O'Rourke [EMAIL PROTECTED] ___ 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 . ___ 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 ___ 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] Tight Skirts...
Sounds like the age old debate in the hifi world about the sweet sound of tube amplifiers vs. the hard sound of clearly superior modern solid state amps. Preferences aside about slopes and shape factors... I'd like to have MUCH better ultimate rejection... and a true rf clipper would be a nice addition, especially when using QRP. Larry N8LP Ron D'Eau Claire wrote: Merlin, W3ICT wrote: ...nobody else I've observed on this net seems to be as annoyed as I about the bad skirts, high ripple, bad ultimate selectivity, etc. when the K2 is used with the KSB2. ...On sideband, tight skirts (the electronic kind, gentlemen!) are terribly important, maybe more so than on CW. There is nothing neater than listening to a weak SSB signal through an IF system that has a 1.2:1 shape factor. -- My SSB operating is only casual but I can say with half a century of operating behind me that I absolutely LOATHE steep-sided filters on CW. They produce a lot of trash in the bandpass caused by the way they modulate signals on edge of the bandpass. Of course, signals varying at all in frequency, including noise, are amplitude-modulated by the filter slope, with causes further sidebands, etc. A lot of work has been done by both engineers and mathematicians working out the best shape to minimize these effects, but this ol' operator simply likes listening to a big chunk of the band at one time and letting my grey-filter between the ears do the work for me. I use OPT1 a lot for CW, and switch to the narrower filters mostly when I need the improved S/N ratio the narrower bandpass provides to dig for a weak signal. From many QSO's and posts on this reflector and others, I know that I am not alone in that preference. Even so, I bet if you came up with ways to make the improvements you'd like to see, I bet lots of operators who love tight skirts would appreciate your efforts. One thing about Elecraft is that they encourage experimenting and improving. A number of the improvements that have been made to the K2 over the years have been the direct result of someone like you sitting down and saying What if 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 ___ 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] Tight Skirts...
We designed the KDSP2 to improve ultimate SSB filter ultimate rejection in the K2. The KDSP2, with its brick wall SSB filter settings, when cascaded after the KSB2 filter, totally eliminates any residual leakage from strong signals outside the passband. It also tightens the net filter shape factor. The ultimate rejection is 60-75 dB on the xtal filter, which means a strong residual off freq. signal will not activate the K2's AGC, allowing the DSP to do its job without signal degradation. This is how I run my K2 and I hear no difference with strong off frequency signal blow-by between it and the other $3K+ rigs we have in the lab. :-) 73, Eric WA6HHQ Larry Phipps wrote: Sounds like the age old debate in the hifi world about the sweet sound of tube amplifiers vs. the hard sound of clearly superior modern solid state amps. Preferences aside about slopes and shape factors... I'd like to have MUCH better ultimate rejection... and a true rf clipper would be a nice addition, especially when using QRP. Larry N8LP ___ 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] Tight Skirts...
OK Eric... I just picked up my radio used, and I haven't checked the alignment yet... this was just an impression I had. I'll put it on the bench and make some measurements before commenting further. Larry N8LP Eric Swartz - WA6HHQ, Elecraft wrote: We designed the KDSP2 to improve ultimate SSB filter ultimate rejection in the K2. The KDSP2, with its brick wall SSB filter settings, when cascaded after the KSB2 filter, totally eliminates any residual leakage from strong signals outside the passband. It also tightens the net filter shape factor. The ultimate rejection is 60-75 dB on the xtal filter, which means a strong residual off freq. signal will not activate the K2's AGC, allowing the DSP to do its job without signal degradation. This is how I run my K2 and I hear no difference with strong off frequency signal blow-by between it and the other $3K+ rigs we have in the lab. :-) 73, Eric WA6HHQ Larry Phipps wrote: Sounds like the age old debate in the hifi world about the sweet sound of tube amplifiers vs. the hard sound of clearly superior modern solid state amps. Preferences aside about slopes and shape factors... I'd like to have MUCH better ultimate rejection... and a true rf clipper would be a nice addition, especially when using QRP. Larry N8LP ___ 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] Tight Skirts...
You may have just sold me on a KDSP2 down the road Eric. I just ran some tests on my new used K2 (#568), and to cut to the chase... I measured ultimate rejection out 5 kHz as 80dB with the KSB2 OP1 filter in, better than you indicated. But with FL2, which is set for 1.8 kHz, I measured 115dB. Is this a result of the KSB2 being outboard? Larry N8LP Eric Swartz - WA6HHQ, Elecraft wrote: We designed the KDSP2 to improve ultimate SSB filter ultimate rejection in the K2. The KDSP2, with its brick wall SSB filter settings, when cascaded after the KSB2 filter, totally eliminates any residual leakage from strong signals outside the passband. It also tightens the net filter shape factor. The ultimate rejection is 60-75 dB on the xtal filter, which means a strong residual off freq. signal will not activate the K2's AGC, allowing the DSP to do its job without signal degradation. This is how I run my K2 and I hear no difference with strong off frequency signal blow-by between it and the other $3K+ rigs we have in the lab. :-) 73, Eric WA6HHQ Larry Phipps wrote: Sounds like the age old debate in the hifi world about the sweet sound of tube amplifiers vs. the hard sound of clearly superior modern solid state amps. Preferences aside about slopes and shape factors... I'd like to have MUCH better ultimate rejection... and a true rf clipper would be a nice addition, especially when using QRP. Larry N8LP ___ 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] Tight Skirts...
Hi Larry, OP1 is the KSB2's SSB fixed b/w filter, which has been optimized for minimum ripple at one SSB b/w. In SSB it is always used for transmit, but it or any of the CW filter bandwidths can be used for receive. Looks like you are using one of the CW settings at 1800 Hz.. Any of the variable CW filter settings (1800 Hz etc.) use the varactor tuned CW filter on the motherboard. This variable CW filter is really optimized for user settings below 700 Hz. (You can chose what b/w to use in each of the four filter memories for each mode..) Wider CW filter settings will have more ripple and poorer out of filter rejection. We allowed the variable CW filter to be set wider to facilitate quickly tuning the band in CW mode and for simple SSB reception in K2s that do not have the SSB adapter. We recommend using the OP1 filter for most SSB reception. One interesting side note: The SSB OP1 filter can be used with different BFO settings in each of the four SSB filter memory settings, creating low and high cut settings. See the filter calibration section of the K2 and KSB2 manuals for information on setting up the filters. 73, Eric WA6HHQ - Larry Phipps wrote: You may have just sold me on a KDSP2 down the road Eric. I just ran some tests on my new used K2 (#568), and to cut to the chase... I measured ultimate rejection out 5 kHz as 80dB with the KSB2 OP1 filter in, better than you indicated. But with FL2, which is set for 1.8 kHz, I measured 115dB. Is this a result of the KSB2 being outboard? Larry N8LP Eric Swartz - WA6HHQ, Elecraft wrote: We designed the KDSP2 to improve ultimate SSB filter ultimate rejection in the K2. The KDSP2, with its brick wall SSB filter settings, when cascaded after the KSB2 filter, totally eliminates any residual leakage from strong signals outside the passband. ___ 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] Tight Skirts...
Oops! - I missed one point in your email. Yes, the above board mounting of the KSB2 reduces ultimate rejection due to its longer ground return paths. But as you noted, with 80 dB of ultimate rejection, following it with the KDSP2 kills any residual blow by. A number of the $3K and above DSP rigs on the market today take a similar approach to the K2. They use a simple moderate rejection crystal filter followed by the brick wall DSP to gain ultimate filter rejection. The crystal filter does the heavy lifting to keep off frequency signals from pumping the AGC and the DSP cleans up any weak residual blow by that gets past the crystal filter. 73, Eric Larry Phipps wrote: You may have just sold me on a KDSP2 down the road Eric. I just ran some tests on my new used K2 (#568), and to cut to the chase... I measured ultimate rejection out 5 kHz as 80dB with the KSB2 OP1 filter in, better than you indicated. But with FL2, which is set for 1.8 kHz, I measured 115dB. Is this a result of the KSB2 being outboard? Larry N8LP ___ 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] Tight Skirts...
After having fingers burnt while designing very 'srtrong' receivers, may I add comment. IF filters with very tight skirts do allow the recovery of very good SSB audio or CW. To do this the filter must NOT have sharp corners at the top of its 'response', the corners should be a little rounded. i.e. the response at the top, often the top 6db, should approach Gaussian. My understanding of this is that the Group Delay through a filter with SHARP corners varies greatly especially at the corner frequencies, resulting in raspy SSB or as you put it, trash on CW. After the slight rounding at the top, the skirts can drop at a rate of knots. Cohn style Ladder filters are poor when Group Delay is considered. Other types of Ladder filter at mid HF using 14 crystals can yield SSB bandwidths, 0.2db ripple, symmetry, 6/60db shape factors of 1.2 or sometimes a bit less, and stopband attenuation of 100db. How the filter is built and terminated are very important considerations, and for my part I prefer ladder filters with an even number of crystals for reasons of mesh tuning. SSB and CW bandwidth filters can also be built at low VHF, but the CW ones difficult for mass production. How much filter stopband attenuation is useful at a given offset is determined in the greater part by how much noise is produced by the LO driving the mixer ahead of the filter and post mixer amplifier (if the type of mixer requires the isolation). Reciprocal mixing is one bugbear. To take advantage of 100db stopband attenuation the LO must be quiet. The effect of noise/signals on the skirts is tied to the linearity of the filter, and Ron, here we could spend hours!! The filter between the ears is super, it also tracks! 73, Geoff. GM4ESD Merlin, W3ICT wrote: ...nobody else I've observed on this net seems to be as annoyed as I about the bad skirts, high ripple, bad ultimate selectivity, etc. when the K2 is used with the KSB2. ...On sideband, tight skirts (the electronic kind, gentlemen!) are terribly important, maybe more so than on CW. There is nothing neater than listening to a weak SSB signal through an IF system that has a 1.2:1 shape factor. -- On March 04, 2005, Ron AC7AC wrote: My SSB operating is only casual but I can say with half a century of operating behind me that I absolutely LOATHE steep-sided filters on CW. They produce a lot of trash in the bandpass caused by the way they modulate signals on edge of the bandpass. Of course, signals varying at all in frequency, including noise, are amplitude-modulated by the filter slope, with causes further sidebands, etc. A lot of work has been done by both engineers and mathematicians working out the best shape to minimize these effects, but this ol' operator simply likes listening to a big chunk of the band at one time and letting my grey-filter between the ears do the work for me. ___ 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] Tight Skirts...
Eric wrote: The SSB OP1 filter can be used with different BFO settings in each of the four SSB filter memory settings, creating low and high cut settings. I installed the mod kit to widen my OPT1 filter and I'm really pleased with it. Listening to AM stations, the K2 sounds as good as most any communications receiver I've ever had and, with an external speaker, as good as most AM radios I have. I have programmed in several different BFO frequencies to allow me to shift that passband around a bit - sort of pre-programmed passband tuning - that is very handy to provide the best response when listening to various rigs and voices. I'm strictly a casual SSB operator so I'm concentrating on the quality of the audio, not in digging in the mud for the weak ones. I'll leave that for CW G You can call me an easy listening SSB operator. 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
