RE: [Elecraft] Is a K2 Realignment Advisable
Jim Harris wrote: > 1. Recently I've noticed when it is initially turned > on the received frequency is about 100 hz high judged > by the pitch of people's voices that I know. After > 20-30 minutes they drift to near exact frequency. And Bill, AA4LR replied: I had this sort of problem before I installed the PLL and BFO stability mods. Your K2 may be recent enough to have come with these modifications. Bill offers excellent comments and replies. I happened to turn my K2 on early today to check WWV at 10 MHz. Within a minute of turning it on, I was listening to WWV and the dial read 40 Hz high: 1.04. (See below* for my method of finding Zero Beat in SSB mode if you're curious) A half hour later zero beat was exactly at 1.00 kHz I just checked it now, about 11 hours later and it's still at 1.00 kHz I've found that typical since adding the BFO and PLL Reference Oscillator (L.O.) stability mods. It isn't always 10,000.00 kHz, but within 10 or 20 Hz of the right frequency. If you're seeing a 100 Hz shift, I suspect you're missing one or the other of the two oscillator mods - perhaps both. The rigs varied a lot before the changes were made. Ron AC7AC *SSB "Zero Beat": Tune in WWV in either upper or lower sideband mode so it sounds "close" then press/hold CW RV to change instantly to the other sideband. (That button works in SSB as well as CW). If you aren't exactly on frequency, you'll hear the pitch of the tone jump up or down. Tune in 10 Hz steps until you hear the direction of the jump change. For example, when I switch from L to H, I may hear the tone go up in pitch. So I increment the frequency 10 Hz higher, then switch from L to H again. If the pitch goes even higher, I went the wrong way, so I tune 20 Hz lower. Change from L to H again and see if the tone goes up or down. Now it should definitely go down. Tune down another 10 Hz and switch from L to H again. Keep this up until suddenly the tone jumps up instead of down in pitch. That means that I just passed the optimum tuning point. Either zero beat was the last 10 Hz point or it's between 10 Hz points. Note that every time I switch sidebands the SAME direction: L or low to H or high. You can go either way, just make sure you switch back before checking at the next frequency! You don't have to match tones. You only need to be able to tell that the tone shifted direction and whether it went up or down. ___ 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] Is a K2 Realignment Advisable
On Feb 13, 2006, at 10:33 AM, Jim Harris wrote: My K2/100 (S/N 4787) is about 10 months old. My question is at what point, or ever, should all the initial alignments be repeated? There are several reasons for asking the question other than electronic components simply drifting a bit with age. Old tube-type rigs required this every year or so, because the heat aged the components. Modern components and equipment are much better and don't get nearly so hot. 1. Recently I've noticed when it is initially turned on the received frequency is about 100 hz high judged by the pitch of people's voices that I know. After 20-30 minutes they drift to near exact frequency. I had this sort of problem before I installed the PLL and BFO stability mods. Your K2 may be recent enough to have come with these modifications. 2. When initially turned on and transmitting right away I've had reports of distortion like I'm crowding the mike. Ditto the above. 3. When doing the initial alignment I had a terrible time with zero beating due to bad hearing. A frequncy counter finally helped solve that to some degree. The K2 is never going to be a precise frequency meter. Due to the nature of the tuning mechanism, it could have an error as large as 30 Hz. I wouldn't sweat a re-calibration unless you find it to be a kHz or two off. 4. I did not use spectrogram as it seemed confusing and my radio seemed to play well enough without it. It is still equal to or better than my IC746Pro. Programs like spectrogram can really help to adjust the filters accurately. I just hate to fix it if it's not broke. But, I'm wondering if I could squeeze a little more performance out of it. I hate to have my K2 on the bench for 2-3 days and not be able to use it. Well, what does everyone say. Go for it or not? Thanks for the help and bandwidth. Wait until you want to make a mod or some other change. Enjoy it in the meantime. 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] Is a K2 Realignment Advisable
Jim, Yes, there is a special set of 4 filters labeled RTTY filters in the K2 - they can be turned on and off via the menu. These 4 filters are independent of the settings used for the other modes (CW and SSB). The RTTY filter set also allows independent adjustment of the menu SSBC parameter - it would normally be set to 1-1 for the best IMD performance on transmit. Your BFO range may limit the filter bandwidth that you can achieve should you attempt to use a narrow filter aligned at a high tone because the BFO range is not adequate to handle it. You will be able to adjust one sideband or the other as a narrow filter, but normally not both, so you may have to manipulate the sideband reversal capability of your RTTY hardware or software to adjust for this situation. Adjusting the filters to demodulate tones below 1kHz is usually not a problem (as is th ecase for most soundcard data modes), but if you attempt to demodulate the RTTY high tones 2175 and 2225 Hz in a narrow filter, you can expect to run out of range. 73, Don W3FPR > -Original Message- > > While chasing 3Y0X on the upper bands I realized those > bands may no be doing as well as the middle and lower > bands and especially on RTTY receive. As the K2 is > only capable of doing RTTY with AFSK I'm presuming LSB > mode would be used like other rigs. The received RTTY > in MMTTY on the K2 looks much more ragged and seems > less copyable than with my IC-746Pro. Is there a > special filter setting for RTTY? > > Now to find some time to work on it and make a great > rig even better. There is just too many things do and > not enough time to do them when you are retired. -;) > > Thanks and have a great day!! > > Jim, AB0UK > ___ 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] Is a K2 Realignment Advisable
Jim, The K2 does not seem to need periodic re-alignment because there is not a lot of drift in the component values over time and the design is on the conservative side, so it is forgiving of minor alignment errors. BUT - If you want optimum performance, do take whatever steps necessary to get the alignment correct the first time and every time you do it (usually needed when components are changed, mods added, or other work on the hardware inside the box). It does not sound like you achieved optimum alignment when you initially did it, so for that reason alone, I would say you will benefit from repeating it. As for your voltages that are 'out of spec' - if you measured within 10% of the value listed in the manual, that is within spec - outside that range usually means that you need to find the source of the anomoly and correct it. The 100 Hz drift that you mentioned is within the K2 spec for operating from a cold start from 25degrees C. If your shack ambient temperature is lower than that, you may see more drift, but judging from peoples voices can be problematic too, better to measure it with a known standard - how much does it drift if you tune carefully to WWV? I highly recommend that you use Spectrogram to set your filters. It sounds complicated to describe it in words maily because we try to describe what to do in detail and anticipate any questions or stumbling bolcks that may arise for you, but once you run through the procedure, I predict that you will find it very easy. Waiting through the boot process for Windows and double-clicking the icon is a harder step than running the Spectrogram application to align a K2 - but I have done it many, many times. 73, Don W3FPR > -Original Message- > > My K2/100 (S/N 4787) is about 10 months old. My > question is at what point, or ever, should all the > initial alignments be repeated? There are several > reasons for asking the question other than electronic > components simply drifting a bit with age. > > 1. Recently I've noticed when it is initially turned > on the received frequency is about 100 hz high judged > by the pitch of people's voices that I know. After > 20-30 minutes they drift to near exact frequency. > > 2. When initially turned on and transmitting right > away I've had reports of distortion like I'm crowding > the mike. > > 3. When doing the initial alignment I had a terrible > time with zero beating due to bad hearing. A frequncy > counter finally helped solve that to some degree. > > 4. I did not use spectrogram as it seemed confusing > and my radio seemed to play well enough without it. > It is still equal to or better than my IC746Pro. > > 5. Several voltages and frequency ranges were > slightly out of tolerance but again overall it seemed > to align okay and initial performance seemed okay. > > 6. I'm now using the receiving antenna port and am > trying to dig out DX and other weak signals. > > I just hate to fix it if it's not broke. But, I'm > wondering if I could squeeze a little more performance > out of it. I hate to have my K2 on the bench for 2-3 > days and not be able to use it. Well, what does > everyone say. Go for it or not? > > Thanks for the help and bandwidth. > > Jim, AB0UK > K2/100 S/N 4787 > > ___ 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
